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7th Grade Science Week 24 CCA
Test is: February 24, 2012
1.
Explain selective breeding: the mating (breeding) or fertilization of plants and animals for specific
genetic traits. Example: race horses for endurance and speed, sheep for fine wool, plants for higher
yields, plants for disease or drought resistance
2.
Organisms can reproduce sexually or asexually, which type of reproduce would increase the rate of
Natural Selection and why? Name an example of an organism that uses this type of reproduction.
Asexual reproduction, because it happens faster with less time between the production of new
Generations. Mutations, traits (good or bad) can be passed form one generation to the next quicker.
Bacteria are a good example.
3.
List some adaptations that would be beneficial to survive in the following biomes:
Desert: roots that are deep and widely spread out, waxy leaves and stems, ability to store water, active
at night rather then day, burrowing into sand, concentrated urine
___
Tundra:bludder, thick fur, white fur, hibernation, migration, grow close to ground (plants), bloom and
And reproduce quickly (during shorten warm season)
___
4.
Name some advantages of the following adaptations:
Claws: climb trees, grasp and hold onto prey, defense, digging, etc.
Beaks: can be specialized for food bird eats – nuts, insects, seeds, fish, etc.,
Thumbs:easier to grip and manipulate objects, pull plants apart, build things, etc.
Gills: allow organism to breath underwater
Hollow Bones:reduces mass of birds so they can fly
5.
What is biodiversity? Why is it important? The variety of organism found on the plant, or within a
given ecosystem (biome). Diversity is important to keep ecosystems in balance, help aid the survival
of organisms – usually offers a variety of food sources (choices), variety of adaptations that aid in
survaival of a species etc.
6.
How can humans affect an ecosystem?
Humans can encroach on an ecosystem through
development (building), using the area for recreation, increase pollution of the system, over
population is the greatest threat because it increases all of the negative effects of human interaction
7.
What is an invasive species or introduced species? How can they negatively affect biodiversity?
An introduced / invasive species is one that is not native to the area, in other words humans brought
the plant or animal in form another part of the world. Once “transplanted” the species does very well
and begins to “crowd” (force) out native plants and animals. Some will produce chemicals that do not
other species to grow in the soil near by, produce a hugh number of seeds or offspring, aggressively
hunt and eat native animals. They can reduce the number of native species in an area therefore
decreasing biodiversity.
8.
What is a dichotomous key used for? They are used by taxonomist to identify and name organisms.
9.
Why do some animas migrate?
Move to more favorable climates, follow water and food sources,
Reproduction, increase chance of survival
10.
Why do some animals hibernate?
11.
What is a microhabitat? List at least 3 examples.
A very small specialized habitat within a larger
ecosystem.
Pond, Rotten Log, Clump of Grass, Tidal Pool, Garden
12.
Compare Photosynthesis and Cellular Respiration
To survive cold weather condidtions
PHOTOSYNTHESIS
Uses Carbon Dioxide
Releases Oxygen
Takes place in chloroplasts
Build molecules (sugar)
CELLULAR RESPIRATION
Uses Oxygen
Releases Carbon Dioxide
Takes place in mitochondria
Breaks down molecules to release energy
Read the experiment below and answer the questions that follow.
Students made paper helicopters that had rotors of different lengths then followed the procedure below:
1.
they dropped each helicopter 4 times form a set height
2.
timed how long it took for the helicopters to each the ground
3.
averaged the time for each helicopter
4.
compared average drop time to rotor length
13.
What is the independent variable in this experiment?
Rotor Blade length
14.
What is the dependent variable in this experiment?
Flight time (how long it takes to land)
15.
Name at least 2 controlled variables in this experiment?
helicopter
Drop height, type of paper, shape of
16.
What is a possible hypothesis (if….then) for this experiment?
If the rotors of a helicopter are
long / short (choose one) then the helicopter will fly for a longer / shorter length of time. (just a
possible example)
17.
Which axis would the independent variable go on? X-axis
DRY - MIX
18.
Which axis would the dependent variable go on?
DRY – MIX
DRY = dependent, responding, Y axis
MIX = manipulated, independent, X axis
Match the definition to the vocabulary term
Y-axis
1. __C__ Structural Adaptation
a. Looking like something dangerous to
avoid being eaten
2. _B___ Behavioral Adaptation
b. How an organism acts that makes it
better able to survive in its environment
3. _E___ Physiological Adaptation
c. How an organism is looks or is built
that enables it to survive in its environment
4. _A___ Mimicry
d. Blending into the surrounding to avoid
detection
5. __D__ Camouflage
e. A particular way an organism’s body works
that allows it to survive in its environment
Define the following words using a dictionary.
Toxic – poisonous or harmful
Herbicide – chemical meant to kill plants
Omnivore – organism that feeds on both meat and plants
Carnivore – organism that feeds only on meat
Herbivore – organism that feeds only on plants
Analogy – comparison between two things that ordinarily have NOTHING in common
Nocturnal – able to stay awake at night, sleep during the day.
Diverse offspring – offspring are not identical to parents; variety of different traits from
both parents
Forage – to go look for; to seek out
Determine how an adaptation gives a survival advantage to an organism. Match the Survival
Advantage to the Trait.
Trait__________________
Survival Advantage________________________
__B_ Gills
a. Insulates against cold
_K__Tightly-packed feathers
b. Gives ability to breathe underwater
_J__Seed production
c. Move where food is most available
_A__Blubber
d. Camouflage protects against predators
_I__Large ears
e. Lighter body weight for flying
__D_Body colors match habitat
f. Attracts pollinators
__C_Seasonal migration
g. More individuals to watch for and defend
against predators
_E__Hollow bones
_F__Flowers
_G__Living in groups
_H__Hover in air
h. Ability to look for prey or obtain food from a
stable vantage point
i. Ability to better listen to surroundings, such as
approaching predators, and to dissipate heat
j. Spreads offspring
k. Waterproofs body
Write out the three parts of the cell theory.
1. Cells are the basic unit of life
2. All living things are made of cells.
3. All cells come from pre-existing cells.