Homework 3:
Use the
book or hand out.
Name_______________________________________
1. In an ecosystem, why are there more herbivores than carnivores?
2. How is the role of a decomposer different that of a producer?
P.46-47
P42-43
3. What is precipitation? P49____________________________ When liquid turns to water vapor_______________
4. Condensation, evaporation and precipitation are processes in the ______________which is by the ______? P49
5. Give an example of mutualism? P30-31__________________________________________________________________________________________________
6. List the three types of symbiosis. P30-31_________________________________________________________________________________________________
7. Which organism benefits in parasitism- the parasite or the host? P30-31
8. Which kind of symbiosis is the relationship between decomposers and producers?
P30-31_______________________________
8. Why does natural selection favor mutualism more than parasitism?________________________________________
9. List two abiotic factors. P7_____________ ____________List two biotic factors. P7 _____________ ____________
10. A species goes _____________ if it is not able to adapt to changes in it's environment. P100 What is a gene pool p99___
__________________________________________________________________________________________________
11. What kind of resource is not replaced quickly? P83 _____________________________________________________
12. What is extinction? P100 __________________________________________________________________________
13. List the layers of soil. P118___________________________________________________________________________________________________________________
14. Which layer of soil has the most organic material like decaying animal and plant matter? P118___________________
15. How do sediments move? P134______________________________________________________________________________________________________________
16. What is the benefit of having an ozone layer? P147______________________________________________________
17. What is the trapping of heat in our atmosphere called? P150______________________________________________
18. What kind of energy is stored in fossil fuels? P159_____________________________________________________
19. What kind of energy turns a turbine? P159 ______________________________________________________________________________________________
1. How does natural selection produce
adaptations in a species?____________________
_________________________________________
_________________________________________
2. When the hare population increased, what
happened to the lynx population? Why?
________________________________________
________________________________________
________________________________________
3. How do you think an increase in the lynx
population affected the hare population? Why?
______________________________________________________________________________________________
4. What other factors could have caused a decrease in the hare population.__________________________________
5. Define the terms predation, predator, and prey in your own words. Give an example of a predator-prey relationship.
Identify the predator and the prey.
The formation of any fossil is a rare event. Usually only the hard parts of the organism, such as the bones or shells of animals, form
fossils. Most fossils form when organisms that die become buried in sediments. Sediments are particles of soil and rock. When a
river flows into a lake or ocean, the sediments that the river carries settle to the bottom. Layers of sediments may cover the dead
organisms. Over millions of years, the layers may harden to become sedimentary rock.
1. Most fossils form when organisms that die become __________________ in sediments. What takes longer to from
an igneous rock or a sedimentary rock?______________. Why do dead organisms need to get buried to form fossils?
_________________________________________________________________________________________________
A river ends its journey when it flows into a still body of water, such as an ocean or a lake. Because the river water is no longer
flowing downhill, the water slows down. At this point, the sediment in the water drops to the bottom. Sediment deposited where a
river flows into an ocean or lake builds up a landform called a delta.
1. What gets deposited at a delta? (P135)
2. Draw a delta at the of a mouth of a river. (P135)
3. Why do fossils form in a delta more than on the top of a mountain?
4. What kind of rock are fossils found in?
Word Bank:
Delta
weathering
erosion
sediments
deposition
5. _______________________ is the movement of rock particles by wind, water, ice, or gravity. The process that breaks
down rock and other materials at Earth’s surface is called ________________________. The agents of erosion lay down
sediment in new locations in a process called ________________________.The material moved by erosion is called
________________________. When sand and soil settle in large deposits at the mouth of a river a _________ forms.
6. Place these step in order of making a sedimentary rock. Erosion, weathering, deposition, and cementation. (p110)
Weathering and erosion work together continuously to wear down and carry away the rocks at
Earth’s surface. Soil is the loose, weathered material on Earth’s surface in which plants can grow.
Soil is a mixture of rock particles, minerals, decayed organic material, water, and air. Together,
sand, silt, and clay make up the portion of soil that comes from weathered rock. If you dug a hole in
the ground about half a meter deep, you would see the different soil horizons. The A horizon is
made up of topsoil, a crumbly, dark brown soil that is a mixture of organic material, clay, and other
minerals. The B horizon, often called subsoil, usually consists of clay and other particles washed
down from the A horizon, but little organic material. The C horizon (parent material) contains only
partly weathered rock.
1. How does weathering and erosion work together to make topsoil?
2. In the image above, circle the smallest sediment.
3. __________________________ is a mixture of rock particles, minerals, decayed organic material, water, and air.
4. How is topsoil different than subsoil?
Decomposers—organisms that break down large chemicals in dead organisms into small chemicals. Decomposers are
“nature’s recyclers.” They return basic chemicals to the environment for other living things to reuse. For example, the leaves
of many trees die in autumn and drop to the ground. Decomposing bacteria spend the next months breaking down the
chemicals in the dead leaves. The broken-down chemicals mix with the soil and can then be absorbed by the roots of nearby
plants. Symbiosis (sim bee oh sis) is a close relationship between two species that benefits at least one of the species.
5. Describe the symbiosis between decomposers and producers.
6. Why does topsoil have more organic material than subsoil?