9. Every Species has its Niche Flashcards
What is an ecological niche?
how a species uses the biotic and abiotic resources in the environment
their ‘role’ in the community, for example Darwin’s finches occupy different foraging niches
Why do polar bears not live in Montreal?
lack of suitable habitat, the climate doesn’t produce the things that it needs
ex. pack ice = seals to hunt
What does Gause’s competitive exclusion principle explain?
no two species can coexist on the same limiting resource WHICH MEANS no two species can coexist in the same ecological niche
(referencing competition to explain niches)
Why do polar bears not live in Antarctica?
they diverged from the ancestral brown bear which is a northern species -> they couldn’t travel through to tropics to Antarctica even though they technically could survive there
Why do species have limited distributions?
the habitat they are adapted to might be limited (aka ecological niches)
evolutionary history (evolution affects distribution)
there are barriers to movement
How can species overcome the barriers to distribution?
humans can intervene and use transplant experiments
if they are successful, this shows that the problem was likely barriers to movement and not a lack of a suitable habitat
How successful are local transplants?
they usually fail - there is usually no other local suitable habitat or they would have already established there
How successful are long-distance transplants?
usually around 10% of attempts are successful (10% rule of establishing)
10% of species that establish become invasive (so 1% of all attempts)
we don’t really do as many transplants anymore because we know of the potential negative effects (used to be more common and taste-based)
What effects does an invasive species have on an ecosystem?
severe negative effects on the receiving ecosystem, ecological and economic
one of the primary causes of the loss of biodiversity (number 1 threat on islands and number 3 or 4 threat in mainland areas)
What are some examples of invasive species
rabbits in Australia, rats & pigs & goats, asian carp
Explain the implication that habitat protection is essential
habitats must be protected to protect niches
if key habitats that limit a species distribution are removed or degraded then endangerment is likely
in Canada we have the Species at Risk Act that keeps an eye on this
Explain the implication that we must be careful when introducing new species
the group responsible for moving a species must be the one to produce proof that it won’t cause any harm (a precautionary principle)
we need to be attentive when trading (shipping things), travelling (tourists can sneak things in and out), and gardening (a lot of the plants in Canada are exotic!)
