8. Every Species has its niche

Question 1

Describe Gause’s Competitive Exclusion Principle.

Answer 1

• Either species cultured alone: growth curve.
• When 2 species are cultured together (in a lab for example), one goes extinct and the other one survives.

What does that mean?
- No 2 species can coexist on the same limiting resource or ecological niche.

Question 2

Who am I?

How a species uses the biotic and abiotic resources in the environment. Its “role” in the community

Answer 2

Ecological niche

Question 3

Why are the polar bears not in the Antarctic? (even if they have a suitable habitat there)?

Answer 3

They diverge from an ancestral brown bear, and brown bears are northern. Tropical regions are a barrier to their dispersal.

Question 4

Why do species have limited distributions?

Answer 4

1. Habitats to which they adapted may be limited (ecological niches)
2. Evolutionary history (barriers to movement)

Question 5

How can we know why species have limited distribution?

Answer 5

Transplant experiments

Question 6

What are the implications of successful transplant experiments?

Answer 6

Means there are likely barriers to movement, not lack of suitable habitat.

Question 7

T/F: Smaller scale transplant experiments are usually more successful

Answer 7

False

Question 8

a) Fill in the blank: Local transplant experiments usually ____ (fail/succeed).
b) Why? Exceptions?

Answer 8

a) fail.
b) there is usually no habitat or they would have already established. Exceptions: Very poor disperses: fish in lakes (local transplant usually works)

Question 9

How often do long-distance transplants succeed?

Answer 9

10% rule of establishing.

Question 10

How much of introductions become invasive in a transplant?

Answer 10

10% of exotic species become invasive. So 1% of introductions become invasive and can cause extinctions of other species. Usually happens on islands.

Question 11

Why do invasive exotic species causing extinction of other species usually happen on islands?

Answer 11

Small
No possibility of rescue
No evolution of mammals

Question 12

Key findings of Every species has its niche:

1. _____ _____ is essential. (Why)
   a) What are the implications of the Species at Risk Act?
   b) T/F: Canada has been rightfully fulfilling his duty of care toward our nation’s wildlife since 2006?
   c) What was the legal victory for endangered species across Canada?
2. Be ____ when introducing new species
   a) The burden of proof should be on the ___ to demonstrate no effect.
   b) _____ _____: Until we know otherwise, we can’t bring it in
   c) Areas of concern (3)

Answer 12

1. Habitat protection. If the key habitats that limit a species distribution are removed or degraded then endangerment is likely.
   a) “habitat that is necessary for the survival or recovery of a listed wildlife species and that is identified as the species’ critical habitat in the recovery strategy or action plan for the species.”
   180 days following the identification of the critical habitat of an endangered, threatened or extirpated species (in the recovery strategy or action plan), all of this habitat on federal lands is legally protected.
   b) False
   c) Court ruling means Department of fisheries and oceans must overhaul recovery plans.
2. Careful
   a) Mover
   b) Precautionary Principle
   c) Trade, travel, gardening

Question 13

Highlights: Every species has its niche

1. Species are limited by ____ and ____ _ ____
2. ____ ____ is essential for endangered species
3. Local transplants usually ___ and nothing to worry about
4. Long-distance transplant: __ establish
5. _/10 become invasive, or _/100 introductions
6. Transplants endanger ____ species
7. _____ consequences.
8. Moving species: ____ ____

Answer 13

1. Habitat and barriers to dispersal
2. Habitat protection
3. Fail
4. 1/10
5. 1/10, 1/100
6. Local
7. Economic
8. Precautionary Principle