Download Ecology Test Review

Ecology Test Review
1. What are the 5 levels of organization in an ecosystem?
1. Organism
2. Population
3. Community
4. Ecosystem
5. Biome
2. Name which level from above would go with each description.
Frog - organism
Frogs, birds, plants - community
Temperate Forest - biome
Frogs - population
Frogs, birds, plants, rocks, and wind – ecosystem
3. What is the difference between biotic factors and abiotic factors?
Biotic factors: living things (plants, animals, fungi, protists,
bacteria)
Abiotic factors: nonliving things (sunlight, moisture, temperature,
soil, wind)
4. What is the difference between a producer (autotroph) and a consumer (heterotroph)?
Producer: gets energy from nonliving resources (sunlight)
Consumer: gets energy from living/once-living resources
5. Below is an energy pyramid. Divide it into 5 levels and name each trophic level. Give an example
of each.
6. What happens to the amount of energy between each level as you move up?
Energy decreases as you move up each level through the food chain –
this is because some energy is “lost” to the environment as heat and
some energy is used by that level to stay alive
7. Why are many more producers needed to support the consumer levels?
This is because of the fact that less energy is passed on to the
above levels so there needs to be more producers to pass on enough
energy to support the primary consumers
8. What is the difference between a food chain and a food web?
-Food chain: shows a sequence of feeding relationships from one
producer and a single chain of consumers (linear; one thing eats
another, that gets eaten by something else, etc.)
-Food web: shows/emphasizes complex feeding relationships/energy
flow in an ecosystem
9. What are the 5 cycles of matter and why are they important to all living organisms?
- Water Cycle: circular pathway of water on Earth; all living
things are made mostly of water
- Oxygen Cycle: cycles indirectly though ecosystems via
photosynthesis and respiration; living things need oxygen to do
cellular respiration
- Carbon Cycle: carbon moves from the atmosphere, through the food
web and back to the atmosphere; all living things contain carbon
(**carbon can be added to the atmosphere by burning fossil
fuels**)
- Nitrogen Cycle: certain bacteria in the soil or in root nodules
of plants are able to change gaseous nitrogen into ammonia, which
is released into the soil and transformed into ammonium.
Bacteria change the ammonium into nitrate that plants need;
plants take in the nitrogen to use and then it becomes part of
them and moves through the food web as things eat plants or
something that ate plants; returns to atmosphere and soil as
things die and are decomposed
- Phosphorus Cycle: occurs from weathering of rocks, moves through
the food web and back to the soil during decomposition; if too
much phosphorus is added to crops (in fertilizer) it could cause
an algae bloom if it gets into the groundwater (runoff during
rain) and that could negatively impact the other organisms living
in the water (pond/lake)
10. What is the difference between a habitat and a niche?
Habitat: all aspects of an area where an organism lives (biotic and
abiotic factors)
Niche: includes all the factors an organism would need to survive,
stay healthy, and reproduce (food, abiotic factors, behavior)
11. Explain 2 important ways in which species interact.
Competition: when two organisms fight for the same limited resource
(fighting for food)
Predation: relationship where one organism eats another (snake eats
a mouse)
12. Explain the three types of symbiotic relationships.
Mutualism: both species benefit (shark and barberfish – shark gets
cleaned and barberfish gets food)
Commensalism: one species benefits and the other is unharmed (shark
and shark suckerfish – shark is unharmed but the suckerfish get a
“free ride”)
Parasitism: one species benefits and the other is harmed (mosquito
carrying the malaria parasite and humans)
13. What are 2 ways that populations can increase and decrease? Explain them.
1. Exponentially: rapid increase or decrease in population due to an
abundance of resources or lack of resources (ex – rabbits that
were brought to Australia had no natural predators there and had
abundant food, so their population increased exponentially)
2. Logistically: population growth when resources are limited; this
can cause the population to drop if something happens to those
limited resources (ex – if animals live on an island, they are
limited to the food available to them on the island, so there
would be a maximum amount of individuals that could survive on
the island due to limited food)
14. What is the difference between an exponential growth and a logistic growth?
Exponential growth occurs when there are unlimited resources and
logistic growth occurs when resources are limited
15. What is a carrying capacity?
The maximum number of individuals in a population that the
environment can support
16. Describe the difference between density dependent and density independent limiting factors.
- Density-dependent limiting factors are affected by the number of
individuals in a given area (predation, competition, parasitism,
disease)
- Density-independent limiting factors limit population growth no
matter how many individuals there are (unusual weather, natural
disasters, human activities)
17. Describe the difference between primary and secondary succession.
- Primary: when a community/ecosystem is started by pioneer species
where there never was an ecosystem before (ex – as Earth’s
temperatures are increasing, the polar ice caps and glaciers are
melting – this is exposing land that was never inhabited before
so if plants begin moving in and then animals, etc. that would be
primary succession)
- Secondary: when a community is regenerated by remaining species
(ex – if there is a forest fire and almost all living things in
that area are wiped out, those that are left will be the first to
inhabit that area and will begin to rebuild that ecosystem)
18. What characteristics determine a biome?
A biome is a major community of organisms that is classified by
temperature, precipitation, and plant life
19. How has the human population been able to grow and not yet reach its carrying capacity?
This is due to technological advances in medicine and farm equipment
that keeps us healthy for longer and helps us get more food to give
to more people
20. Explain the difference between renewable and nonrenewable forms of energy.
- Renewable: cannot be used up or replenish themselves over time
(wind, water, sunlight)
- Nonrenewable: used faster than they form (coal, oil)
21. List three different ways that the burning of fossil fuels has changed our atmosphere.
1. Acid rain: pollutants get into the water cycle and cause the pH
of rainwater to drop, lowering the pH of lakes and streams and
harming plants and animals
2. Greenhouse Effect: sunlight enters Earth’s atmosphere and instead
of the heat reradiating back into space, it is trapped in our
atmosphere by greenhouse gases (like CO2) which come from burning
fossil fuels
3. Global Warming: trend of increasing global temperatures (caused
by greenhouse effect)
22. How does habitat fragmentation disrupt an ecosystem?
Occurs when a barrier (roads, houses built, etc.) is created within
the habitat and this prevents an organism from accessing its entire
habitat
**Habitat corridors are a solution to the problem if something must
be built and fragment the ecosystem by giving organisms some way to
access their entire habitat (although avoiding the fragmentation in
the first place would be ideal)
23. Explain how introduced species and invasive species can disrupt other organisms in an
ecosystem.
These organisms can push out native species (forcing them to go
somewhere else and disrupt another ecosystem or even become extinct)
and disrupt existing food chains – sometimes they cause damage in
the habitat they move into and this can also have economic impacts
in addition to causing disruption in the food chain/web in that area