Interspecific Competition Flashcards
What is interspecific competition
Competition between populations of different species that causes a demonstrable decline in the fecundity, survival or growth of both species
What are the 3 basic effects of interspecific competition
- one species causes an increase in the survival, growth or fecundity of the other
- one species causes a decrease….
- one species has no apparent effect on the other
When interaction is put into a table with + and - and 0, what is +-?
Predation/parasites
When interaction is put into a table with + and - and 0 what is +0?
Commensalism - presence of one species is a prerequisite for another
When interaction is put into a table with + and - and 0 what is -0?
Ammensalism - one species has an adverse effect on another , but to no advantage to itself
When interaction is put into a table with + and - and 0 what is ++?
Mutualism - both species benefit
When interaction is put into a table with + and - and 0 what is - -?
Interspecific competition - both species suffer
What is competitive exclusion?
When interspecific competition leads to one of the species being out competed by the other, and it is excluded from the habitat
What is an example of competitive exclusion?
Floor beetles, t confusum and castaneum, confusum prefers cold dry
What does competitive exclusion imply?
No two species can use exactly the same resources without one of them becoming extinct
What is the niche theory?
The multidimensional niche that an organism occupies, called the N-dimensional hyper volume
What is a fundamental niche?
The one is which a species can live in the absence of all competitors , a very large niche
What is a realised niche?
A smaller niche when competition or predation present
What is niche partitioning?
When organisms competing for the same niche change it so that there is less competition
What 2 types of niche portioning are there?
- Change the components of their niches (resource partitioning)
- Change themselves morphologically (character displacement)
What are the effects of resource partitioning?
- reduces amount of interspecific competition
- niches are now narrower
- restricts the individual members of the population
- increases intraspecific competition
Give an example of character displacement
Mud snails, 2 species feed on algae,
When found alone both about 3.5mm, but when together, one 3mm and one 4mm
Also Darwin’s finches
Describe the interspecific competition between rats and ants
Both eat seeds, ants eat smaller seeds in general
Rats hinder ants more than ants hinder rats
What is a guild
A group of species exploiting the same resource in a similar way
How could several ant species co-exist
- Any size, related to seed size
2. Any foraging strategy, group (high seed density) or individual (low seed density)
