Lecture 5-Introducing the niche Flashcards
What is ecological niche?
-the limits for all important environmental variables, within which individuals of a species can survive, grow and reproduce -includes environmental and resource gradients
What is a fundamental niche?
-the largest niche that an organism or species can occupy in the ABSENCE of interactions with other species including disease organisms (essentially unknowable)
What is realised niche?
-the portion of fundamental niche that is occupied by a species in the PRESENCE of interactions with other species (e.g. competitors, predators etc.)
What is the competition exclusion principle?
-complete competitors cannot coexist -the fundamental niches may overlap a lot but the realised won’t
Is it possible for niches to overlap in one dimension provided they are separated on at least one other?
-yes
How does predation affect the prey species?
-negatively- the fundamental will overlap and realised won’t at all
Can the realised niche be bigger than the fundamental niche?
-yes, if there is facilitation where the interaction with other species increases the fitness of a species = positive interaction
How does competition for resources affect niche?
-alter the dimension and affect fitness
Are niches different from the bell curve?
-yes
Are niches fixed in time and space?
-no
Are they hard to measure?
-yes
Do niches only apply to animals?
-no, all organisms
Describe what’s happening:
- the predation has negative effects on the prey species
- fundamental niches overlap but the predation makes the prey species adapt
Describe:
- the competitive excluison principle
- complete competitors can’t coexist so they adapt
Describe:
- predators have to eat
- so the realised niches overlap
- the right: not likely to happen to this extent
Describe:
- facilitation
- where species benefits from the presence of another species= postive interaction
