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Chapter 27: Introduction to Animals
Section 1 Characteristics of Animals
Objectives:
Identify the features that animals have in common.
Distinguish radial symmetry from bilateral symmetry.
Summarize the importance of a body cavity.
Identify how scientists determine evolutionary relationships among animals.
Characteristics of Animals (Video clip)
__________________________
__________________________
____________ make their own food
Must seek out __________ sources.
Movement in many different ways
to seek:
o ____________
o ____________
o ____________
Sexual Reproduction
Differentiation of ____________
General Features of Animals
Heterotrophy
Animals are _____________________ — that is, they __________ make their own food.
Most animals move from place to place searching for food.
Once food is located, it is eaten and then digested in a _______________ inside the
animal’s body.
Comparing Autotrophs and Heterotrophs (Video Clip)
Autotophs obtain energy by _________________ their own food.
o Most autotrophs, such as plants, use ________________ as their source of energy.
o Other autotrophs use ___________ in their environment as their source of energy.
Hetertrophs must take in food to meet their energy needs.
Mobility
Animals are unique among living things in being able to perform rapid, _____________
movements.
Animals move by means of ___________________________, specialized cells that are
able to ______________ with considerable force.
Animals can swim, crawl, walk, run, and even fly. In fact, _________________________
_____________________ among animals, in insects, pterosaurs (extinct reptiles from the
time of the dinosaurs), birds, and bats.
Multicellularity
All animals are _________________________.
In spite of differences in body size, there is _______________________________ in the
_____________________________________________ that make up these animals.
The cells on the skin of your hand are roughly the same size as the cells in the heart of a
whale or in the wing muscle of a hummingbird.
Comparing Organisms That Are Unicellular and Multicellular (Video clip)
Unicellular Organism
Multicellular Organism
_____________ : 1
________ : over 100 trillion
# of cells
Example & Number of cells
Can individual cell live on its own?
Diploidy
With few exceptions, animals are ____________, meaning adults have ____ copies of
each chromosome, ______ inherited from their father and _____ from their mother.
Only their ________________ (egg and sperm) are _______________.
A great advantage of diploidy is that it permits an animal to _______________________
between the two copies of a set of chromosomes, creating _________________________
of genes.
Comparing Haploid and Diploid Cells (Video Clip)
Examples of organisms
Diploid
Haploid
____________ & many other
___________________
____________________ &
________________ (sperm &
eggs) of many eukaryotes
# of sets of chromosomes
# of chromosomes in humans
Sexual Reproduction
__________________________________________________ by producing gametes, as
do many plants, fungi, and protists.
The _____________________________________________ than the males’ sperm cells.
Unlike the egg cells, the sperm cells of animals have a flagella and are highly _________.
Absence of a Cell Wall
Among the cells of multicellular organisms, only animal cells lack rigid _____________.
The _________________________________________________________________
that other multicellular organisms do not have.
You may not realize this, but there are ________________________________________
_______________________. Cells called macrophages, for example, act as mobile
garbage collectors, crawling over tissues and removing debris.
Blastula Formation
In all animals except sponges, the _____________ (_____________________________)
undergoes cell divisions that form a hollow ball of cells called a __________________.
Cells within the blastula eventually develop into three distinct layers of cells—
___________________, ___________________, and ___________________.
These layers are called the ________________ tissue layers because they ____________
_______________________________________________________________________.
Origin of Animal
Tissues and Organs
Cleavage and Blastula Formation (Video clip)
After fertilization, a zygote undergoes ____________, a series of rapid mitotic divisions.
The fertilized cell first divides into ____ cells each of which is roughly _________ the
size of the original.
Each of these ___________________ cells divides again. The resulting cells are roughly
_______ the size of the fertilized egg.
This process continues until the zygote is a mass of cells. While the ________________
___________________________, the total ________________________________ has
remained roughly the _____________ as that of the fertilized egg.
The zygote has become a hollow ball of cells called a ____________________. The
hollow space in the center of the blastula is called a blastocoel.
Cleavage and Blastula Formation
Tissues
The cells of all animals except sponges are organized into structural and functional units
called __________________.
Tissues are ______________________________________________________ that work
together to perform a specific function.
Body Symmetry
All animals have their own particular _____________________, a term used to describe
an animal’s ___________, _________________, and ____________________________.
An animal’s body plan results from a pattern of development ______________________
into the animal’s __________________________________________.
Sponges have the simplest body plan of all animals. Sponges are asymmetrical, or _____
____________________, and sometimes their shape depends on where they are growing.
Radial Symmetry
•
Animals with radial symmetry have body ____________________________ around a
___________________________, somewhat like the spokes around a bicycle wheel.
•
A plane passing through the central axis divides the organism into roughly equal halves.
•
Today’s radially symmetrical animals are ___________________. Most move slowly or
drift in ocean currents.
Bilateral Symmetry
•
The bodies of _______________________________ show bilateral symmetry, a body
design in which there are _________________________________________________.
•
A plane passing through the animal’s ____________________ divides the animal into
mirror image halves.
•
Most bilaterally symmetrical animals have evolved an anterior concentration of sensory
structures and nerves, a process called _______________________________.
Radial and Bilateral Symmetries
Symmetry in Body Structure (Video clip)
The symmetry of an animal describes the overall pattern or structure of its body.
Sponges are irregular in shape; they are called ______________________________.
In an animal with ________________ symmetry, the body parts are arranged in a circle
around a central point.
Sea anemones have radial symmetry. You can cut through the center of a sea anemone in
any direction and both halves would look the _______________.
Most animals have _____________________ symmetry
Two sides of their bodies ____________ each other. There is only one way you could cut
through the center of a bilaterally symmetrical organism for both halves to look the same.
Animals with bilateral symmetry usually have a ________________________________.
Cephalization (Video clip)
Cephalization is the concentration of sensory
organs and nerves in the anterior end of an
animal. Cephalized animals have a _________.
Animals that are bilaterally symmetric have an
________________ and a _______________
and are therefore usually cephalized.
Cephalization is a major evolutionary change
because it allows animals to seek out mates, sense
food and avoid prey as they move in the forward
direction through their environment.
Internal Body Cavity
Bilaterally symmetrical animals have one of three basic kinds of internal body plans.
The body plan may include a body cavity, or _________________, a ________________
_______________________ found between the body wall and the digestive tract (gut).
This space is lined with cells that come from mesoderm.
Animals with ________________________________ are called acoelomates.
Animals called _________________________________ have a body cavity located
between the mesoderm and endoderm.
Coelomates have a true coelom, a body cavity located entirely within the ____________.
A ___________ coelom provides an internal space where mesoderm and endoderm can
be in contact with each other during embryonic development.
Body Cavity (Video clip)
Many animals that are bilaterally symmetric have a body cavity or coelem, a fluid filled
space that forms between the digestive tract and the outer wall of the body during
development.
o __________________________ are coelomates, animals that have a true coelom
that is completely surrounded by mesoderm.
o The true coelom ____________________________________________________
suspending and protecting digestive organs.
o It also provides a firm base for the animal’s muscles to push against.
o The fluid in the coelom also serves as a __________________ for nutrients and
waste that diffuse into and out of the animal’s cells.
Some bilaterally symmetric animals like ______________ worms are pseudocoelomates.
o Their body cavity is surrounded by mesoderm on one side and endoderm on the
other side.
A few animals that are bilaterally symmetric do not have a coelom at all.
o For example, ____________________ have bodies that are completely filled with
tissue. These animals are called __________________________.
Three Body Plans of Symmetrical Animals
Body Segmentation
Segmented animals are composed of a series of repeating, similar units called ________.
Segmentation underlies the organization of all “advanced” animals and is easy to observe
in some animals, such as ______________________.
In _____________________, segments are ___________________________________,
but there is evidence of segmentation in a ______________________.
Segmentation (Video clip)
In animals, segmentation refers to a body composed of a series of
_________________________________ that can move independently
permitting great ______________ and _______________.
Within the phylum Arthropoda, segments may look different and
have different functions. A small change in a segment can modify it
for eating, defense or reproduction.
In some arthropod species, like this butterfly, the ___________ exhibit
segmentation, but many segments are fused in the ____________.
Kinds of Animals
Kingdom Animalia contains about ________ major divisions called _______________
(singular, phylum), depending on how certain organisms are classified.
To visually represent the relationships among various groups of animals, scientists often
use a type of branching diagram called a __________________________________. A
phylogenetic tree shows how animals are _____________________________________.
The animal kingdom is often divided into _____ groups: _________________________
(animals without a backbone) and ______________________ (animals with a backbone).
Evolutionary
Relationships in
the Animal
Kingdom
The Animal Body: An Evolutionary Journey
Animal Body Features and Phylogeny (Video clip)
A phylogenic tree is a visual representation of the evolutionary relationships among
different animals.
o Animals that are more _______ related are shown on the same branch of the tree.
o Animals that are more _________ related are shown on different parts of the tree.
These relationships are based on the presence or absence of various traits.
o For example all of the animals on the bracketed portion of the tree share the trait
of being multicellular. Only the protists at the base are unicellular.
o All animals except the sponges have true tissues. They are grouped together in the
part of the tree in the red bracket.
o Animals that have body cavities are grouped together in the region of the tree
indicated by the green bracket.
o Animals that have jointed appendages, such as crabs, shrimp & lobsters, are all
grouped together on the branch circled in purple.
Each of these groupings - multicellularity, tissues, body cavities and jointed appendages represent key evolutionary innovations found in animals that are alive today.
Phylogenetic Tree (Video clip)
A phylogenetic tree is a family tree that shows the
evolutionary relationships thought to exist between
groups of animals. This phylogenetic tree shows the
relationship thought to exist between vertebrates.
The branch points on phylogenetic trees represent
common ancestors.
o For example, reptiles and birds are believed
to share a relatively recent common
ancestor.
o Therefore reptiles and birds lie relatively
close to a branch point.
o The common ancestor for reptiles and
mammals lived sometime before the
common ancestor for reptiles and birds.
o Therefore the branch point or reptiles and mammals is further down the
phylogenetic tree.
o Lampreys and hagfishes shared a common ancestor with reptiles back in time.
o Therefore the branch point for reptiles and lampreys is even further down the
phylogenetic tree.
Section 2: Animal Body Systems
Objectives:
Summarize the functions of the digestive, respiratory, circulatory, nervous, skeletal, and
excretory systems.
Compare a gastrovascular cavity with a one-way digestive system.
Differentiate open from closed circulatory systems.
Distinguish asexual from sexual reproduction.
Tissues and Organs
Digestion
_______________________ organisms and sponges digest their food _______________
______________________. All other animals digest their food extracellularly (outside of
their body cells) within a ________________________________.
Simple animals, such as the hydra and flatworms, have a _________________________
__________________, a digestive cavity with only ________________________.
Other animals have a digestive tract (gut) with _____________________, a mouth and an
anus.
Digestion
A hydra has a gastrovascular cavity, while a roundworm has a digestive tract in which
food travels in one direction only.
Respiration
In simple animals, ________________________________________________________
__________________ directly with the environment by __________________.
The uptake of oxygen and the release of carbon dioxide, called ____________________,
can take place only across a moist surface.
Some aquatic (and a few terrestrial) animals respire with ____________, very thin
projections of tissue that are rich in blood vessels.
Parts of the Human Respiratory System (Roll over) Label!
10
3
Fish Gills (Video clip)
Fishes breathe with gills.
Gills are supported by _______ sets of curved bone on each side of the fish’s head called
gill arches.
Each gill has a double row of tiny tissue projections called gill filaments.
These are rich in blood vessels and have a large surface area for rapid _______ exchange.
Water flows from the fish’s mouth over its gills through the gill filaments.
As the _______________________________ the gill filaments and ________________
_________________, blood travels toward the ________________________.
Deoxygenated blood moves against the water and ________________________ from the
water.
The blood releases carbon
dioxide back into the water.
This pattern of flow is
called _________________
exchange.
It allows for more efficient
gas exchange than if the
blood and water flowed in
the same direction.
Circulation
In complex animals, oxygen and nutrients must be transported to these body cells by a
__________________________________.
In an open circulatory system, a __________________________________ containing
oxygen and nutrients through a series of vessels out _____________________________.
In a _______ circulatory system, a heart pumps blood through a system of blood vessels.
Comparing Open and Closed Circulatory Systems (Video clip)
Both transport ___________________________ to cells and _________ away from cells.
Open circulatory system:
o A blood like circulatory fluid called ____________________ is pumped from
vessels into a body cavity and then is returned to vessels.
o Ex: arthropods and most mollusks
Closed circulatory system
o A heart circulates blood through a ______________________________________
that form a ___________________________.
o Materials pass into and out of the blood by _____________________ through the
blood vessels.
o Ex: cephalopods and ______________________ (us!) 
Conduction of Nerve Impulses
Nerve cells (________________) are specialized for _____________________________
in the form of electrical impulses (conduction).
Bilaterally symmetric animals have clusters of neurons called ____________________.
More-complex invertebrates, such as the grasshopper, have brains with sensory
structures, such as eyes, associated with them.
The hydra has a simple __________________________, while the flatworm and the
grasshopper have more-complex nervous systems.
Support
Many soft-bodied invertebrates have a _________________________ skeleton. A
hydrostatic skeleton consists of water that is contained under pressure in a closed cavity,
such as a gastrovascular cavity or a coelom.
Other invertebrates, such as insects, have a type of skeleton known as an ____________,
which is a rigid ______________________________ that encases the body of an animal.
An _______________________ is composed of a hard material, such as ___________,
embedded within an animal.
Comparing Exoskeletons and Endoskeletons (video clip)
Check the appropriate box.
Exoskeleton
Rigid external skeleton that encases the body of an
animal
Rigid internal skeleton embedded within an animal
Act as frames that support and protect the animal’s
internal organs
Provides surfaces against which the muscles can pull
Arthropods and mollusks are examples
Vertebrates and echinoderms are examples
Some vertebrates such as a turtle
Does not grow with the animal; must be shed and
grown again as the animal gets bigger
Grows w/ an animal & is able to support a large
heavy body
Endoskeleton
Excretion
The term excretion refers to the __________________________ produced by cellular
metabolism.
Simple aquatic invertebrates and some fishes excrete ___________________ into the
water through their skin or gills by diffusion.
Other animals, especially terrestrial animals, _______________________________ to
nontoxic chemicals, like __________. As the excretory system ___________________
______________________, water and other useful substances are returned to the body.
Asexual Reproduction
Reproduction that ________________ involve the _______________________________
is called _______________________ reproduction.
An unusual method of asexual reproduction is ________________________________, in
which a new individual develops from an unfertilized egg.
Animals that reproduce asexually are _____________ able to _____________________
____________________________.
Sexual Reproduction
In sexual reproduction, a new individual is formed by the ______________ of a male and
a female gamete.
Gametes are produced in the ________________________. The ___________ produce
the male gametes (___________), and the ________________ produce the female
gametes (__________).
Some species of animals, called hermaphrodites, have both ______________________.
Most aquatic animals simply release the male and female gametes near one another in the
_______________, where fertilization occurs. This method is called ________________
fertilization because the egg is fertilized __________________ of the female’s body.
Most terrestrial animals reproduce sexually by means of internal fertilization. In _______
fertilization, the union of the sperm and egg occurs _____________ the female’s body.
Sexual Reproduction (Video clip)
Reproduction is the process by which new offspring are produced.
In sexual reproduction, the genetic material from ________________________________
combines to produce offspring.
This makes these offspring _______________.
Sexual reproduction enables species to _______________ rapidly to new conditions.
Chapter 37: Introduction to Body Structure
Section 1 Body Organization
Objectives:
Identify four levels of structural organization within the human body.
Analyze the four kinds of body tissues.
List the body’s major organ systems.
Evaluate the importance of endothermy in maintaining homeostasis.
Levels of Structural Organization
The body is organized into four levels: ________________________________________.
A ________ is a group of similar cells that work together to perform a common function.
The body has four basic kinds of tissues: ______________________________________
_______________________________________________________________________
Tissue
Organ
Organ System (Video clip)
In most multicellular organisms, cells are organized into tissues.
A tissue is a group of similar cells that perform a common function.
o The function of the spongy tissue in the lung is to take in oxygen and release
carbon dioxide.
An organ is a collection of tissues that carry on a particular function of the body or
specialized task.
o The function of the lungs is to take ______________ from the air and deliver it to
the blood and take __________________ from the blood and transfer it to the air.
An organ system is a set of organs that work together to perform a set of related tasks.
o The lungs are part of the respiratory system, a group of organs that work together
to help you breathe.
Four Kinds of Tissues
Epithelial tissue __________________________________________ and ___________
________________________________ from damage and dehydration.
Nervous tissue consists of nerve cells, which _________________ throughout the body.
Various kinds of connective tissue support, ____________, and ____________ the body.
Muscle tissue enables the _________________ of body structures by muscle contraction.
Human Body Tissues
Body Tissues (Thumbnails)
The human body has 4 main types of tissue: nervous, connective,
muscle and epithelial.
Nervous tissue contains special cells called neurons that ________
and _______________ messages in the form of electrical impulses.
Connective tissue (CT) binds, supports and protects structures in the body.
o ____________ is a mineralized CT with blood vessels for nourishment.
o _______________ and lymph are also types of CT
o Adipose CT is composed of fat cells and lies under the top layers of skin to help
insulate the body and store energy.
o _________________ are CT that attaches skeletal muscle to bone.
o ____________________ are CT that attaches bone to other bone.
Muscle tissue is composed of cells that can __________________.
Cardiac muscle, found in your heart, pumps blood through the body.
Skeletal muscles are attached to your bones and contract to help you ______________.
Smooth muscle handles body functions that ____________________________________
______________ such as the movement of food through your digestive system.
Stem Cells
Embryonic stem cells are early, undifferentiated cells that _________________________
_______________________________ in the developing body.
____________________ stem cells will ________________________________.
Adult stem cells are not as versatile and do not divide indefinitely.
Organ Systems
Body organs are made of combinations of _____________________________________
________________________________________________________________________
An organ system is a group of organs that work together to carry out major activities or
processes. Some organs function in more than one organ system.
Major Organ Systems of the Human Body
Overview of Organ Systems (Video clip)
Body Cavities
The human body contains four large fluid-filled spaces, or ________________________,
that ____________________________________________________________________.
These body cavities are the _____________ cavity (heart and lungs), __________ cavity
(brain), _______________ cavity (digestive organs), and _________ cavity (spinal cord).
Cavities of the Human Body
Inside the Human Coelom
Endothermy
Like all mammals, ______________________________________. Humans maintain a
fairly constant internal temperature of about 37°C (98.6 °F).
The human body uses a great deal of energy to maintain a constant body temperature.
Advantage of Endothermy (video clip)
Unlike ____________________ that __________ their ___________________________
along with the ______________________________________, endothermic animals such
as mammals and birds generate body heat internally.
Most endotherms, like humans, are also _______________________ meaning they
maintain a fairly constant internal temperature regardless of environmental conditions.
To maintain our body temperature, we __________________________________ and
________________________________.
Endotherms have the advantage to live in a wide range of ___________________.
The ability to ______________________ between vastly different habitats is another
advantage of endothermy.