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Chapter 6 Review
Changes in Ecosystems
5th Grade
inherit- receiving of parents genes; offspring receive half from the mother
and half from the father
mutation- a change in an organisms genes
structural adaptation- a body part that helps an organism survive in its
ecosystem; ex. A frog’s long, sticky tongue for catching insects
behavioral adaptation- inherited behaviors that help organisms survive; ex.
A duck flying south for the winter
pesticide- poisons that kill insects; ex. DDT
extinct- has no members of its kind of species left alive on earth; ex.
Tasmanian wolf
endangered- the population of the organism is so low that it is in danger of
becoming extinct; ex. The gray bat
1. Explain what DNA is. It contains all the information needed for making
an organism; found in all the nucleuses of cells
2. How do earthworms affect the environment as they move through soil?
They enrich the soil with the waste that they give off from their digested
material and the holes that they make bring oxygen to the roots of plants
3. When parents pass on genes what percent comes from the mother and
what percent comes from the father? 50% from the mother and 50% from
the father
4. Name 4 structural adaptations of a frog and explain how they help the
frog survive. The sticky pads on a tree frog help it to climb; Their green skin
help the blend in and avoid predators (camouflage); eyes on the top so when
it goes under water it can still see predators and prey; strong legs and
webbed feet help it swim
5. Name two behavioral adaptations of a duck and how they help it to
survive. Flying south for the winter to find food; It’s quack will warn its
babies or others about predators
6. How can new species be introduced into an environment? They can stow
away like rats on a ship; be brought by humans
7. Describe the situation with the zebra mussel. They were brought in by
ships by accident, they have no natural predators here so their population
exploded, they stop up pipes and take the food of other natural mussel
species
8. What is a learned behavior and give an example of one? A behavior that
they learn from their parent; a cub learns to hunt from its mother
9. Explain what a mutation is. A change in a gene
10. Can a mutation be helpful, harmful, or both? It can be helpful or
harmful
11. Why does acid rain form and what does it hurt? It forms from air
pollution and it hurts the whole ecosystem where it falls (plants, lakes,
streams, and the organisms)
12. If a lake becomes polluted with acid rain, what can be done to help the
situation? Lime can be added to change the pH but it takes a while for the
lake to return to normal
13. Explain what DDT is and how it ended up causing the bald eagle to
become an endangered species? DDT is a pesticide that when spread on
crops ended up in streams that eagles caught their fish from. After eating the
fish with DDT in their system they laid eggs with thin shells. These eggs
did not hatch and the eagle population reached the endangered level until
DDT was banned.
14. Why did the dodo become extinct? It’s a flightless bird that survived
well on an island until sailors arrived and brought rats, pigs, and monkeys
into the ecosystem. The birds could no longer defend themselves or fly to
safety on other islands.
15. How do pesticides and antibiotics cause insects and bacteria to become
resistant to their chemicals? They develop adaptations to living around
antibiotics and pesticides. When they do they pass these traits on to their
offspring. And the diseases the bacteria cause become harder to treat and the
insects cannot be killed.
16. Tell what a variable is in an experiment. Variables are the things that
can be changed in the experiment.