1. Ecology Review

2. Question 1 What is ecology and what do ecologists do?
Ecology is the study of living things and how they interact with one another and their environment. Ecologists are people that study these relationships.
An example would be the study of how zebra mussel populations affect native clam and phytoplankton in U.S. rivers and lakes.

3. Question 2 Explain the difference between a habitat and an ecosystem.
Habitat: The area where a specific species lives.
Ecosystem: An area that includes all living organisms and the abiotic factors that influence the region (like weather).

4. Question 3
Niche: A niche is the role that an individual organism plays in its nonliving and living environment (how it "fits" into its ecosystem).
If a particular niche is already filled, introducing a species that requires the same resources will cause competition between the two.
If a certain niche is no longer filled, the ecosystem will become unbalanced. For example, the extinction of a top predator would allow prey populations to increase dramatically.
What is a niche? Explain how this impacts an ecosystem when a species is added or removed.

5. Question 4 What is biodiversity and why is it important?
Biodiversity is the variety of living things. Depending on the scientist you ask, biodiversity can be the number of species living in an ecosystem, genetic diversity within a species, or the number of species living on Earth at a given time.
What is biodiversity and why is it important?
There are many views on why biodiversity is important.
We need a variety of plants and animals to produce medicines.
Many people enjoy outdoor recreational activities.
We can learn about species from the past by studying current species.
Nature inspires art, music and cultures.

6. Question 5 What does a food web represent? How do these diagrams work?
A food web shows the flow of energy within an ecosystem. Arrows point from food to consumer because the organism that’s eating is gaining energy from the one being eaten.

7. Question 6
Producers, Consumers and Decomposers.
Producers are the source of energy for the whole ecosystem, without them everything would eventually die.
Consumers help producers complete their life cycles by spreading seeds and pollinating. They also feed other consumers and eventually decomposers.
Decomposers break down dead organisms and help to recycle nutrients in an ecosystem.
Within a food web, there are always ___________, ___________ and ___________. Why are all three necessary?

8. Question 7
Trade-off: An exchange of one thing in return for another, especially losing an advantage for another more desirable one.
By introducing Nile Perch to Lake Victoria, locals were given a source of protein but the lake lost many species of smaller fish.
What is a trade-off? Give one example that we have talked about in class and one additional example from your own experience.

9. Question 8
What is the difference between biotic and abiotic factors? Why are both important in an ecosystem?
Biotic: Living
Abiotic: Non-living (never, ever was alive…)
All living things play a specific role in their ecosystem and abiotic factors help with important processes and ingredients, like those necessary in photosynthesis.
- phytoplankton

10. Question 9
How can introduced species affect an ecosystem? How do they become invasive? Compare and contrast the impacts of zebra mussels and swamp crawfish.
Introduced species have the potential to become invasive. An introduced species may compete with native species for resources such as food, habitat, and water. Without natural predators to keep their numbers down, they may takeover a certain niche within the ecosystem.
Zebra mussels have few natural predators and have been consuming large amounts of plankton and leaving little to no food for native clams and other filter feeders. They are spreading through freshwater lakes and rivers in the U.S.
Swamp crawfish are competing with local crawfish for food and habitat. Their population is increasing in Pine Lake.

11. Question 10
What is carrying capacity and what are some factors that can impact it?
The Carrying Capacity of a species is the maximum population that can live in an ecosystem long term.
This can be affected by changes in climate, availability of food, diseases, habitat loss and more.

12. Question 11
What is a population? Does it always remain the same? If not, should we be concerned?
Population: Individuals of the same species living in the same area. Example - All of the swamp crawfish in Pine Lake are a population.
Populations fluctuate (increase and decrease) so there is only reason to be concerned if numbers remain extremely high or extremely low for long periods or don’t follow typical patterns for that area.

13. Question 12
Describe the impacts humans can have on ecosystems. Be sure to mention Lake Victoria and Easter Island in your answer!
Humans often have negative effects on ecosystems including deforestation for construction and farming, pollution from factories and vehicles, use of pesticides, and more. In Lake Victoria, humans intentionally introduced Nile Perch which then became invasive
and caused the extinction of many species of cichlids.
On Easter Island, humans unintentionally introduced species that
also caused extinctions. Overconsumption
of resources also led to many extinctions.