Download AP Biology Summer Assignment

AP Biology Summer Assignment
Welcome to AP biology. Our class is intense, with a lot of material that needs to be covered in a relatively
short amount of time. Please be aware that part of taking this class is commitment to being on time, on
task, and occasionally learning content on your own. We look forward to working with each one of you
next year!
We know the words “summer assignment” tends to send chills down any high school student’s spine, but
these assignments will be beneficial to you as we start the school year. The reason we are giving you a
summer assignment is to keep your mind sharp so you are ready to hit the ground running! It is also
important to realize that there is simply not enough time to cover the content of the course without a head
start.
Because AP Central has changed the Biology assessment we need to change the way we approach the
summer assignment. Please adhere to the following criteria when completing your assignments.
 It is important that you handwrite your work. This does not mean typing out your answers but
instead handwriting your responses in the space provided on the following worksheets.
 Work needs to be completed alone. You do not get to collaborate on the assessment so you
should not be collaborating on these assignments.
 Detail needs to be included in your answers. While we understand that you will need to use the
internet to review content, we also expect that you will properly cite your sources and give credit to
those individuals that aided in your understanding of the material.
The following worksheets and packets need to be completed no later than September 8th
1. Graphing and Data Skills Practice Packet
2. Cell Structure and Function Packet
3. Amazing Cells: Cell Communication Web Activity
4. Classification Worksheet
5. Classification and Taxonomy Packet
6. Creating Phylogenetic Trees from DNA Sequences: Student Worksheet
If these assignments are lost you are able to obtain another copy be visiting our school webpage at
BWHS. Have a great summer and please contact us if you have any additional questions.
Mrs. Amber Poniatowski: [email protected]
Ms. Lauren Snow: [email protected]
Name: _______________________________________________________ Date: _________ Block: _______
Graphing and Data skills practice Packet
Math and Statistics for AP Biology - Research the answer to the following questions
1. In designing an experiment or other scientific study, why do scientists sample from a population
rather than using an entire population?
2. Suppose you are designing an experiment to test the effects of nicotine on the heart rate of rats.
What are the disadvantages of having too small a sample size (i.e., testing on too few rats)? What
are the disadvantages of having too large a sample size (i.e., testing on too many rats)?
3. Explain the difference between discrete variables and continuous variables. Give an example of each.
4. Explain the difference between quantitative and categorical variables. Give an example of each.
5. What is a null hypothesis?
6. What are some steps that scientists can take in designing an experiment to avoid false negatives?
Graphing Practice
Graphing is an important procedure used by scientists to display the data that is collected during a
controlled experiment. Line graphs must be constructed correctly to accurately portray the data
collected.
A graph contains five major parts:
 Title
 The independent variable
 The dependent variable
 The scales for each variable
 A legend

The TITLE: depicts what the graph is about. By reading the title, the reader should get an idea
about the graph. It should be a concise statement placed above the graph.

The INDEPENDENT VARIABLE: is the variable that can be controlled by the experimenter. It
usually includes time (dates, minutes, hours, etc.), depth (feet, meters), and temperature
(Celsius). This variable is placed on the X axis (horizontal axis).

The DEPENDENT VARIABLE: is the variable that is directly affected by the independent
variable. Example: How many oxygen bubbles are produced by a plant located five meters below
the surface of the water? The oxygen bubbles are dependent on the depth of the water. This
variable is placed on the Y-axis or vertical axis.

The SCALES for each Variable: In constructing a graph one needs to know where to plot the points
representing the data. In order to do this a scale must be employed to include all the data points. The
scales should start with 0 and climb based on intervals such as: multiples of 2, 5, 10, 20, 25, 50, or 100.
The scale of numbers will be dictated by your data values.

The LEGEND: is a short descriptive narrative concerning the graph's data. It should be short
and concise and placed under the graph.

The MEAN for a group of variables: To determine the mean for a group of variables, divide the
sum of the variables by the total number of variables to get an average.

The MEDIAN for a group of variables: To determine median or “middle” for an even number of
values, put the values in ascending order and take the average of the two middle values.
Example: 2, 3, 4, 5, 9, 10. Add 4+5 (2 middle values) and divide by 2 to get 4.5.

The MODE for a group of variables: The mode for a group of values is the number that occurs
most frequently. Example: 2, 5, 8, 2, 6, 11. The number 2 is the mode because it occurred
most often (twice).
Problem A:
Using the following data to answer the questions below and then construct a line graph.
Number of bubble per minute
Plant A
Plant B
29
21
36
27
45
40
32
50
20
34
10
20
Depth in meters
2
5
10
16
25
30
1. What is the dependent variable and why?
2. What is the independent variable and why?
3. What are the mean, median, and mode of all three columns of data?

Depth :

Bubble Plant A.:
Mean_______ Median _______Mode____

Bubbles Plant B:
Mean_______ Median _______Mode____
Mean_______ Median _______Mode____
4. Title: ______________________________________________________________________________
__________________________________________________________________________________
Problem B:
Diabetes is a disease affecting the insulin producing glands of the pancreas. If there is not enough
insulin being produced by these cells, the amount of glucose in the blood will remain high. A blood
glucose level above 140 for an extended period of time is not considered normal. This disease, if not
brought under control, can lead to severe complications and even death.
Answer the following questions concerning the data below and then graph it.
Time After Eating (Hours)
0.5
1
1.5
2
2.5
3
4
Glucose mL per Liter of Blood
Person A
Person B
170
180
155
195
140
230
135
245
140
235
135
225
130
200
1. What is the dependent variable and why?
2. What is the independent variable and why?
3. What title would you give the table above?
4. Which, if any, of the above individuals (A or B) has diabetes?
5. What data do you have to support this conclusion?
6. If the time period were extended to 6 hours, what would the expected blood glucose level for Person B?
Explain why.
Title:
__________________________________
_______________________________________________________________________________________
Problem C:
Temperatures were obtained in November in a fairly arid area of Nevada. At two different sites,
temperature readings were taken at a number of heights above and below the soil surface. One site
was shaded by a juniper (a plant) whereas the other was not.
Condition
Air
Air
Air
Air
Soil Surface
Humus
Mineral
Mineral
Temperature (OC)
Height in cm from soil surface
150
90
60
30
0
-6
-15
-30
Beneath Forest cover
Unshaded Field
18
18
18
18
16
12
9
7
20
21
20
21
33
19
15
12
Construct a line graph, plot the data, and give an appropriate title in the space below.
Problem D:
A researcher interested in the disappearance of fallen leaves in a deciduous forest carried out a field
experiment that lasted nearly a year. She collected all the leaves from 100 plots scattered throughout the forest.
She measured the amount of leaves present in November, May and August. The percentages reflect the
number of leaves found, using the November values as 100 percent. Complete the table by calculating the
missing percentages.
Collection Date
Ash
Beech
Elm
Hazel
Oak
Willow
November
4271g
3220g
3481g
1723g
5317g
3430g
100%
100%
100%
100%
100%
100%
2431g
3190g
1739g
501g
4401g
1201g
57%
91%
______%
_______%
83%
35%
1376g
2285g
35g
62g
1759g
4g
32%
71%
______%
_______%
33%
0.1%
May
August
Construct an appropriate line graph for the ash and elm leaves on the graph below.
Problem E:
A species of insect has been accidentally introduced from Asia into the US. The success of this
organism depends on its ability to find a suitable habitat. The larval stage is very sensitive to
changes in temperature, humidity and light intensity. Expose to situations outside the tolerance
limits results in a high mortality (death) rate. Study the data table below.
Temperature (oC)
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Relative
Light
Mortality (%) Humidity (%) Mortality (%) Intensity (fc) Mortality (%)
100
100
80
300
0
16
80
90
10
400
0
17
30
80
0
600
10
18
10
70
0
800
15
19
0
60
0
1000
20
20
0
50
50
1200
20
21
0
40
70
1400
90
22
0
30
90
1600
95
23
20
20
100
1800
100
24
80
10
100
2000
100
25
100
0
100
2200
100
Plot line graphs for the effects of temperature and humidity on mortality rates.
9
Name: ______________________________________________________________________ Date: _________________ Block: _____________
Cell Structure and Function
Research the following structures and/or organelles found below using a variety of online resources, this does not include your friends or fellow
students. In your own words describe the function of each structure. Structures underline should also include a diagram. These functions should go
above and beyond the definitions that were given during first year biology. You will need to commit these structures to memory. Every Wednesday
you will be assessed on this material by taking a quiz (1st Quarter: Matching, 2nd Quarter: Multiple Choice Questions, and 3rd Quarter: Free
Response).
Structure
Nucleoid
Nuclear envelope
Cytoplasm
Organelle
Cytosol
Plasma membrane
Endomembrane system
Function
Vesicles
Central vacuole
Cytoskeleton
Nucleus
Nucleolus
Ribosomes
Rough endoplasmic reticulum
Smooth endoplasmic reticulum
Golgi apparatus
Lysosomes
Peroxisome
Contractile vacuole
Mitochondria
Chloroplast
Flagella
Cilia
Cell wall
The Evolution of Cells
Click on the following link: http://learn.genetics.utah.edu/content/cells/organelles/ and answer the questions that follow.
1. Describe how the Earth’s atmosphere has changed over time. How has this impacted the type of organisms that evolved?
________________________________________________________________________________________________________________________
________________________________________________________________________________________________________________________
________________________________________________________________________________________________________________________
________________________________________________________________________________________________________________________
2. Describe how the endosymbiotic theory got its name. __________________________________________________________________________
________________________________________________________________________________________________________________________
________________________________________________________________________________________________________________________
3. “Mitochondria and chloroplast have striking similarities to bacteria cells.” Explain what evidence is used to support this statement.
________________________________________________________________________________________________________________________
________________________________________________________________________________________________________________________
________________________________________________________________________________________________________________________
________________________________________________________________________________________________________________________
4. Describe the pattern of inheritance for mitochondrial DNA (mtDNA). _______________________________________________________________
________________________________________________________________________________________________________________________
________________________________________________________________________________________________________________________
Name: ____________________________________________________ Block: _______ Date: ____________
Amazing Cells: Cell Communication Web Activity
Click on the following link: http://learn.genetics.utah.edu/content/cells/
Once the webpage opens you will see a number of different boxes on which you can click. In this activity you
will focus on the column of five links found on the right-hand side of the webpage under the heading Cells
Communicate. Follow the instructions below and answer the questions that go along with each portion to
increase your understanding of cell communication.
Part 1: The Inside Story of Cell Communication
Read through The Inside Story of Cell Communication to get a brief summary of what cell communication
involves. Take notes in the space provided below.
Part 2: The Fight or Flight Response 3D-Animation
1. What part of our body is often the first to detect signals from our environment?
_____________________________________________________________________________________
2. What are the two primary ways that signals get sent through the body?
_____________________________________________________________________________________
3. What does the video propose could be considered a cell’s sole purpose of life?
_____________________________________________________________________________________
_____________________________________________________________________________________
4. In your own words, what is a signaling cascade?
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
14
5. List and describe the physical reactions that occur due to a triggered stress response.
a. _______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
b. _______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
c. _______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
d. _______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
6. According to the video, an identical signaling molecule can cause either relaxation or contraction of
different types of muscle cells in our bodies. This is due to the different “protein machinery” found in the
various types of muscle cells. Explain the scientific reasoning behind this phenomenon.
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
Part 3: How Cells Communicate During Fight or Flight
7. When cortisol is released into the blood stream it begins a signaling cascade in several cell types. What
are the results?
a. _______________________________________________________________________________
b. _______________________________________________________________________________
c. _______________________________________________________________________________
8. In the animation you watched previously, the video referenced a “signaling molecule.” What are the two
names that can be used interchangeably for this signaling molecule?
a. ___________________________________________
b. ___________________________________________
15
9. It has been reported that people can possess super-human strength when faced with an extreme or
stressful situation. Example: A grandmother is able to lift up a car in order to free her grandson who is
trapped underneath it. What is the possible scientific explanation for this boost in strength or energy?
Part 4: Dropping Signals: Take a break and enjoy dragging and dropping the different signals onto the
various types of cells to see what happens!
Part 5: When Cell Communication Goes Wrong
10. Summarize each of the five ways that cell communication can go wrong. Read each example provided by
this website to get you started; you can incorporate the examples given into your answers, but you will
require additional information from your textbook and/or internet research to fully explain how each of these
happen. Cite your sources please.
a. Losing the signal: ________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
b. When a signal does not reach its target: _______________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
c. When a target ignores its signal: _____________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
d. Too much signal: _________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
e. Multiple breakdowns: ______________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________ 16
_______________________________________________________________________________
11. Find a treatment for a cell communication problem that interests you. (You may not use either of the two
already stated on this website.) Clearly state the problem, the treatment, and explain how that treatment
repairs the issue. Cite your sources please.
17
Name: ______________________________________________________ Date: _________ Block: ________
Classification Worksheet
Use online resource to answer the following questions. This packet will serve as your notes on these terms.
1. Draw a gastrula and label the blastopore and tissue layers. Define the terms diploblastic and triplobastic.
What significance do these terms play in the level of complexity in an organism?
2. Contrast protostomes and deuterostomes. List two examples of each. ____________________________
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
3. Define what the following types of symmetry and list two examples of each.

Asymmetry

Radial Symmetry

Bilateral Symmetry
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________ 18
________________________________________________________________________________________
4. Describe cephalization? _________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
5. There are three main types of body cavities found in animals. Define the following and list two examples of
each.
 Acoelomate
 Psuedocoelomate
 Coelomate
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
Animal Development: We're Just Tubes - Crash Course Biology
Watch the following video and take notes on information not covered in the questions above:
https://www.youtube.com/watch?v=k_9MTZgAhv0
19
Name: ____________________________________________________ Block: _______ Date: ____________
Creating Phylogenetic Trees from DNA Sequences: Student Worksheet
Click on the following link: http://media.hhmi.org/biointeractive/click/Phylogenetic_Trees/01.html
Answer the following questions as you proceed through the activity slides.
12. Briefly explain how scientists draw relationships between organisms based on shared anatomical features.
_____________________________________________________________________________________
_____________________________________________________________________________________
13. How are DNA sequences used to deduce evolutionary relationships? ______________________________
_____________________________________________________________________________________
14. What is one advantage of building phylogenetic trees using DNA comparisons rather than anatomical
features? _____________________________________________________________________________
_____________________________________________________________________________________
15. Watch the video clip on slide 3 and then draw a simple tree illustrating the evolutionary relationships
between gorillas, chimpanzees, humans, and orangutans.
16. Watch the short video on slide 4. How has biotechnology affected the process of building phylogenetic
trees from DNA sequences? ______________________________________________________________
_____________________________________________________________________________________
17. What do evolutionarily related organisms share? ______________________________________________
18. What are two common types of mutations? __________________________________________________
19. Watch the short animation on slide 6 and describe a SNP. ______________________________________
_____________________________________________________________________________________
20. Watch the short animation on slide 7 and described an indel. ____________________________________
_____________________________________________________________________________________
21. Explain the difference between distantly related and closely related organisms in terms of their DNA
sequences. ___________________________________________________________________________
_____________________________________________________________________________________
22. What does it mean to compare “apples to apples” when referring to DNA sequences from different
organisms? ___________________________________________________________________________
_____________________________________________________________________________________
23. Watch the short animations on slide 10 and explain what is meant by “aligning” DNA sequences.
_____________________________________________________________________________________ 20
_____________________________________________________________________________________
24. How is a SNP identified in an alignment? ____________________________________________________
_____________________________________________________________________________________
25. How is an indel identified in an alignment? ___________________________________________________
_____________________________________________________________________________________
26. Look at the information on slide 15. From left to right, identify the base in each box as an indel or a SNP.
Write your answers in the spaces below.
Box 1 (left) _________
Box 2 (center) _________
Box 3 (right) _________
Now click on each box and check your answers to question 15 above.
27. Watch the video clip on slide 17. How can you identify the two sequences that are most similar?
_____________________________________________________________________________________
28. Watch the video clip on slide 18 and describe the link between the length of the line and time.
_____________________________________________________________________________________
29. What is surprising about the placement of hippos on the phylogenetic tree?
_____________________________________________________________________________________
30. Define a branch point (also called a node) on a phylogenetic tree and describe what it represents.
_____________________________________________________________________________________
_____________________________________________________________________________________
31. What is the root? _______________________________________________________________________
_____________________________________________________________________________________
32. What does the node closest to the root represent? ____________________________________________
33. Describe what an unrooted phylogenetic tree represents. _______________________________________
_____________________________________________________________________________________
34. On slides 22 and 23, notice how phylogenetic trees can rotate around nodes and have different shapes.
Notice the relationships between the organisms do not change.
35. Using the information on slide 24, explain how DNA evidence supports the known biology of the seven
cone snails. ___________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
36. Write three conclusions drawn from the information provided in this Click and Learn:
a. __________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
b. __________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
c. __________________________________________________________________________________
__________________________________________________________________________________
21
Classification & Taxonomy Activity
The diversity of life on Earth is astounding. Each organism has a unique body plan which allows it to
survive and adapt to its surroundings. With such an abundance of species, classifying organisms into
different categories is necessary in order to assign each a scientific name and to understand its
evolutionary history. The diversity of living organisms is overwhelming, but after further research and
observation, many likenesses appear. These similarities become the basis for taxonomists to organize
organisms into their appropriate hierarchal categories.
Animals are classified into categories called taxa according to their body plan, phylogeny, and other
similar characteristics. There are seven principle levels that organisms can be placed into: Kingdom,
Phylum, Class, Order, Family, Genus, and Species. All animals are in the Kingdom Animalia. As you
move from kingdom to species, the animals that are grouped together become more closely related at
each succeeding level.
The next level after Kingdom is Phylum, which is the main focus of this activity. Even though there are
approximately thirty-five phyla within the animal kingdom, 98 percent of all animals are classified into eight
of them. To get even more specific, seven of the eight phyla are invertebrates. Invertebrates comprise
most of the animal kingdom, with almost 75 percent of all animals on earth being insects. They out
number humans by a million to one!
From Phylum, animals are then broken down into more specific categories. For example, a shark, a bird,
and a human are all in the Phylum Chordata. What similarities do these animals have? Taxonomists
agree that all these animals have a similar internal skeleton. However, these animals would not be
grouped in the same Class. This process would continue until the animal is classified down to Species.
Note that Sub-phyla do exist, and, there are visible differences not only amongst the different animal
phyla, but also within each phyla.
Procedure:
1. Review the phyla descriptions provided, highlight and take annotated notes on the characteristics
from each phylum.
2. The table on page ten provides a main characteristic of one of the eight main animal phyla in each
block. Using the information in this grid, list the characteristics applicable to each phylum in the
chart provided on the next page. The end product will be a comparison of the main characteristics
of each phylum. Note that some of the characteristics are used multiple times.
22
Porifera
Sponges
The Phylum Porifera consists only of sponges. These animals are entirely aquatic; 98% are found only in
marine environments and a small percentage are found in freshwater lakes and streams. Sponges are
considered the oldest and of the animal phyla. Translated from Latin, Porifera means “pore bearer.”
Sponges play an important role in aquatic ecosystems, filtering particles, including bacteria, out of the
water. The surface of a sponge is covered with a skin that is one cell thick. This skin is penetrated by
numerous small pores and a few larger openings. These larger openings are the entrances and exits for a
complex system of canals and chambers through which the sponge pumps a current of water. The body
of a sponge, between this system of canals, is a loose assemblage of cells that secretes a supporting
skeleton of collagen fibers and mineral spicules made of glass or calcium carbonate. This body carries
out the process of growth, repair, nourishment, and reproduction.
Sponges can filter water at a rate equal to their entire volume in less than a minute. As the sponge pumps
in water at this rate, it captures tiny food particles as small as a single micron in diameter. Choanocytes
are specialized flagellated cells, also called collar cells that enable sponges to pump the water. Since
sponges are filter feeders they often have to filter over a ton of water to secure just a single ounce of food.
Sponges reproduce asexually by fragmentation or budding, sexually using eggs and sperm, or they are
hermaphroditic—a single species with both male and female gametes. Their commercial importance
includes use as bath sponges as well as being tested for possible anti-cancer drugs or antibiotics.
Sponges provide a micro-habitat for other organisms and they aid in cleaning their aquatic environments.
Since sponges are considered the simplest of the all animal phyla, they are important subjects for
analyzing the evolution of animals. Studies indicate that the Phylum Porifera is at the base of the animal
phylogenetic tree.
Features:
* Asymmetrical
* Organized as an assemblage of different kinds of specialized cells, e.g. collar cells
* No tissues
* Skeleton lacking or made of spicules
* Depends on system of water currents for food and oxygen
23
Cnidaria
Jellyfish, Corals, Anemones, Hydras
The phylum Cnidaria includes jellyfish, corals, sea pens, sea anemones, and hydras. This phylum
contains the most venomous marine creature; the Australian box jellyfish. It is known to kill more people
than sharks, crocodiles, and stonefish combined. It can cause shock and heart failure within minutes. Sea
turtles are able to prey upon the box jellyfish because they are not affected by the venom. Most cnidaria
alternate between two different body forms throughout their life: a free-swimming form, called the medusa,
and a stationary form, called the polyp. Both body types follow the same basic plan. They are radially
symmetrical with three layers of tissue. Each species has a single opening that serves as both the mouth
and the anus. That shared opening is usually surrounded by a ring of tentacles, allowing the animal to
capture prey from all directions.
Cnidarians have a defined top and bottom and two distinct layers of tissue: an epidermis outer layer and
an internal gastrodermis. Between these tissue layers is a layer called the mesoglea. In the form of a
medusa, the mesoglea is an elastic, clear jelly with fibers made of protein called collagen. The mesoglea
aids in locomotion by elastically recoiling in response to muscle contractions. Cnidarians’ muscles and
nerves are located at the base of the tissue layers. The internal space, surrounded by the layers of tissue
and mesoglea, is the gut or gastrovascular cavity.
In order to capture prey, cnidarians have stinging cells. Located in their tentacles, these stinging cells,
called cnidocytes, contain tiny, often toxic harpoons, called nematocysts. Triggered by touch or certain
chemicals, nematocysts fire out of the cnidocyte housing at lightning speed. Some hydra can fire these
harpoons with an accelerated force equal to 40,000 times the acceleration of gravity. That’s 10,000 times
the acceleration force of a space shuttle. Once the nematocyst hits it mark, usually lethal poisons are
injected into the prey. The combination of defined tissues, muscles, nerves and a gut allowed ancestral
cnidarians to be the first animals on the planet to show animated behavior. The name Cnidaria comes
from the Latin word meaning “nettle.”
Features:
* Two tissue layers with nerve and muscle tissues
* Nematocysts - structures contained in special cells called cnidocytes or cnidoblasts that can act in both
offense and defense
* Two main life forms - free-swimming medusa (e.g. jellyfish) or stationary polyp (e.g. anemone)
* Radial symmetry
* Extracellular digestion in gastrovascular cavity
24
Platyhelminthes
Flatworms
This particular phylum is one of the lesser-known groups and includes such animals as freshwater
planaria, colorful marine polycads, and parasitic tapeworms and flukes. The name Platyhelminthes in
Latin means “flat worm.”
Fossilized worm tracks in the early Cambrian period hint at the origin of this body plan. While the
classification of Platyhelminthes remains controversial because of the diversity within each class included
in this phylum, flatworms share distinctive features. They are bilaterally symmetrical with a defined head
and tail region and a centralized nervous system containing a brain and nerve cords. Clusters of lightsensitive cells make up what are called eyespots. The head region of the flatworm also contains other
sense organs which are connected to the flatworm’s simple brain. Like most animals, with the exception of
sponges and cnidarians, flatworms possess three tissue layers making them triploblastic. The middle
tissue layer, called the mesoderm, helps form true organs including reproductive organs such as ovaries,
testes, and a penis.
Flatworms are hermaphroditic and capable of sexual and asexual reproduction. They have no circulatory
system or body cavity (coelom), but they do have an excretory and digestive system. Passive diffusion
through the skin supplies oxygen to their body parts. The highly branched gastrovascular cavity distributes
nutrients to their cells.
Most species of flatworms are parasitic—they have evolved protective skin coverings and elaborate
attachment mechanisms to allow them to live inside their hosts.
Features:
* Bilaterally symmetrical with a head and tail
* Centralized nervous system
* Three tissue layers
* Acoelomate
* No circulatory system
25
Annelida
Polychaetes, Earthworms, Leeches
The Cambrian period began approximately 543 million years ago. Of the eight major phyla, two were
known from fossils at this time - Porifera and Cnidaria. Shortly thereafter, a profuse radiation of fossils
representing the other animal body plans occurred over a relatively brief span of about 10 million years.
The rest of the animal phyla evolved during, or shortly after, this evolutionary explosion of new life forms
in the Cambrian period.
The Annelid body plan is equal in complexity to that of chordates. Annelids are bilaterally symmetrical;
they contain three tissue layers and are coelomates. The coelom surrounds a one-way muscular digestive
tract that runs from the mouth to the anus and includes a pharynx, intestine, and other structures.
Annelids have a closed-circulatory system and a segmented central nervous system that includes a
simple brain located in the head region.
One of the distinctive traits of an annelid is that it has segmentation—Annelida means “little ring” in Latin.
Each segment has a number of bristles, called setae, which help the worm move. The evolution of
segmentation is an important development for the annelids because it enabled the specialization of
different body regions. Fluid-filled coelomic compartments were another important adaptation for annelids
because it insulated the gut from locomotor muscles and provided a hydrostatic skeleton enabled these
worms to swim and burrow.
Features:
* Elongate, bilateral body with segmentation
* Triploblastic
* Well-developed coelom
* Closed circulatory system
* Bristle-like structures called setae projecting from body (except in leeches)
26
Arthropoda
Crustaceans, Spiders, Millipedes, Centipedes, Insects
Of all the phyla in the animal kingdom, Arthropoda is by far the largest and most diverse. All arthropods
have segmented bodies and are covered in a hard, yet flexible exoskeleton. Their muscles attach to the
inside of the exoskeleton.
The name Arthropoda means “jointed foot” and refers to their jointed appendages. In order to grow,
arthropods must shed their chitonous exoskeleton periodically in process called molting. When an
arthropod goes through specific developmental stages it is called metamorphosis. Metamorphosis can
bring on radical changes in body design; for example, a dragonfly begins its life in a pond as a swimming
larva and then changes into a completely different-looking winged adult.
Arthropods, like all animals, originated in the sea, but became the first animal group to live on land and
take to the skies. This is likely because arthropods demonstrate a genetic predisposition to adapt to
changing conditions. The diversity and success of the arthropods can be attributed to their versatile body
plans. Key features of which lie in the development of myriad types of appendages: antennae, claws,
wings, shields, and mouthparts. These characteristics enabled arthropods to exploit nearly every niche on
Earth.
Features:
* Hard exoskeleton made of chitin and protein
* Jointed appendages
* Segmented body
* Grows through metamorphosis
* Triploblastic
* Open circulatory system
* Reduced coelom
* Bilaterally symmetrical
27
Mollusca
Clams, Snails, Slugs, Nautilus, Octopus
Animals in this phylum—chitons, snails, slugs, clams, squid, and octopi—show an amazing degree of
diversity. All molluscs have soft bodies. In fact, the name Mollusc means “soft” in Latin. Most molluscs are
covered by a hard shell, which is secreted by a layer of tissue called the mantle; the mantle overlays the
internal organs of the mollusc. Molluscs also have a strong muscular foot, which is used for movement or
grasping. They have gills, a mouth and an anus. One feature unique to molluscs is a file-like, rasping tool
called a radula. This structure enables them to scrape algae off rocks, to drill through the hard shells of
their prey, or catch fish.
The diversity of molluscs demonstrates how a basic body plan can evolve into a variety of different forms
that enable survival in specific environments. For example, the hard shell in a land-dwelling snail is
relatively large and serves to protect the animal. However, in the fast-swimming squid the shell has been
reduced to a small pen-shaped structure.
Features:
* Rasping organ called a radula—present in all groups except bivalves and Aplacophora
* Muscular foot—used for locomotion and other tasks
* A sheath of tissue called the mantle that covers the molluscs’ body and can secrete the shell (if there is
one)
* A mantle cavity that houses the gills or lungs
* A calcium shell is present in most molluscs. Some molluscs have greatly reduced shells: squid. Others
have completely lost the shell feature: slugs, nudibranchs, and octopi.
* Coelomate
* Triploblastic
* Most show bilateral symmetry
28
Echinodermata
Sea stars, Sea Lilies, Sea Urchins, Sea Cucumbers, Brittle Stars
There are about 6000 living species belonging to the phylum Echinodermata. The bodies of echinoderms
are made of tough, calcium-based plates that are often spiny and covered by a thin skin. This tough body
is how they get their name—Echinoderms (echino-spiny, derm-skin).
Echinoderms are exclusively marine animals. This phylum includes sea stars, sea lilies, urchins, sea
cucumbers, sand dollars and brittle stars. Echinoderms do not have a distinct head and tail. Instead, many
Echinoderms begin life as bilaterally symmetrical larvae and later develop into organisms with pentaradial
symmetry.
The mouths of most Echinoderms are located on the underside of their bodies. Echinoderms move, feed,
and respire with a unique water-vascular system ending in tube feet. Sea stars use their tube feet to
slowly pry open clams, mussels, and other prey. Some sea stars can even extrude their stomachs from
their bodies and insert them into the tiny openings between the two shells of bivalves and digest the soft
bodies inside.
An interesting ability of both sea stars and sea urchins is regeneration. If body parts such as legs, tube
feet, or spines are lost they can grow back. Most echinoderms are either stationary or slow-moving but
nevertheless prominent members of the marine environment.
Features:
* Triploblastic
* Coelomate
* Internal skeleton made of small calcium plates
* Five-part radial symmetry
* Water-vascular system that operates the tube feet
29
Chordata
Tunicates, Lancelets, Vertebrates including Amphibians, Reptiles, Mammals
The Phylum Chordata includes a wide range of animals from tunicates that look like sponges, to
vertebrates including fishes, frogs, snakes, birds, and humans. Despite this diversity most all chordates
share certain characteristics at some point in their development. One of these features is a stiffening rod
called a notochord that, in the vertebrates, is later replaced by a bony vertebral column. In most adult
vertebrates the notochord remains as a disk between the vertebrae. Another chordate feature is the
dorsal nerve cord that becomes the spinal cord and brain. Also included in the chordate body plan are
structures called pharyngeal gill slits; these skeletal elements function as jaws and jaw supports, and can
take on a variety of other functions.
The most conspicuous group of Chordates is the subphylum Vertebrata. Chordates have internal
skeletons that enable chordates to grow continuously with no need for molting and can support a large
mass. This feature has allowed some vertebrates to grow to large sizes; consider the African elephant or
the giraffe. This internal skeleton is also credited with enabling the powerful movements of swimming fish.
A major embryonic development in the evolution of vertebrates is the appearance of the neural crest. The
neural crest is a specialized population of undifferentiated, migratory cells that are correlated with the
emergence of vertebrate jaws, skull, and a number of other structures that lead to more complex
organisms. Another feature that likely added to the complexity of vertebrates was the duplication of HOX
genes. Scientists speculate that additional copies of these genes that control organism body plans
provided additional genetic material available to evolve a more complex organism. Both of these
aforementioned features likely offered new opportunities for adaptation.
Vertebrates fall into two main categories: fishes and tetrapods. Tetrapods developed from a distinct
lineage of fishes that possessed internal fin bones. These structures eventually aided in supporting the
weight of animals on land and laid the foundation for arms and legs and the first amphibians. The
development of a shelled amniotic egg enabled tetrapods to remain on land and develop into reptiles,
birds, and mammals. From an ancient reptilian ancestor, two groups of animals, mammals and birds,
independently developed the capacity to maintain a constant body temperature.
Features:
* Notochord
* Single, dorsal, tubular nerve cord
* Phalangeal pouches
* Segmentation
* Post-anal tail
* Bilateral symmetry
30
Characteristic Table:
A1
Bilateral phylum
that added
segmentation
A2
Most have a
calciumcarbonate shell
A3
Five-part radial
symmetry
B1
Hollow body
cavity for food
B2
Three tissue
layers, but no
body cavity
C1
Most members
are parasitic
C2
Water flows
through its body,
full of canals
D2
Body design
basically a tube
within a tube
B3
Fluid-filled
compartments
used for
locomotion
C3
Pioneered jointed
legs
C4
First phylum to
venture into the air
D3
Tube feet used for
locomotion
D4
First muscle and
nerves
C5
Some have
stinging structures
(nematocysts)
D5
Most have inside
skeleton of bones
E2
Some of the
simplest animals
with bilateral
symmetry
F2
Some spines are
little pinchers
(pedicellaria)
G2
No locomotion;
stationary animal
E3
Digestive tract with
the entrance being
the exit
E4
All have
notochord; most
have backbone
E5
Champions of
variations in
appendages
F3
Some nonswimming polyps
F4
Some free-drifting
medusae
G3
Tubular mouth
(pharynx) at midbody
G4
Phylum to which
humans belong
H2
Feeding device
like a toothed,
rasping tongue
(radula)
H3
No symmetry or
consistent body
shape
H4
Exoskeleton made
of chitin and
protein
F5
Some propel,
using their siphon
as a water jet
G5
Hard but flexible
bodies with
interlocking plates
under their skin
H5
Their active
burrowing has
affected global
climate
D1
Increased
complexity made
possible by
much more DNA
E1
All members live
in the ocean
F1
More species
than any other
phylum
G1
Muscular “foot”
used to slide, dig
or jump
H1
Spicules act as a
skeleton to give
it structure
A4
Specialized cells,
but not organized
into organs or
tissues
B4
Jaws and skulls
important in their
evolution
A5
Mantle of tissue
covering the body
B5
Complete
digestive tract with
two ends
31
Name ________________________________________________
Date_______________________
Class Period __________________________________________
Classification & Taxonomy Activity—Answer Sheet
Porifera (5 characteristics)
Cnidaria (6 characteristics)
Platyhelminthes (5 characteristics)
Annelida (5 characteristics)
Arthropoda (7 characteristics)
Mollusca (6 characteristics)
Echinodermata (6 characteristics)
Chordata (7 characteristics)