Behaviour and Speciation Flashcards
What is adaptive radiation?
Diversification of a group of organisms into forms filling different ecological niches
What are new species a consequence of?
cladogenesis
What is cladogenesis?
Branching to produce new species
Speciation means that different types of animal undergo independent divergence maintaining what?
Seperate identities, evolutionary tendencies and fates.
Why is speciation largely based on inferences?
Too fast to be documented in fossil record but too slow to study as it occurs
What are sibling species?
Evolved to look the same as other animals that they are actually distinct from
Sibling species (aphanic species) species are very similar in appearance, behaviour and in other characteristics, but they are reproductively isolated.
When do hybrid zones occur?
When species are so closely related that their offspring can be viable and fertile.
Hybrid zones keep a bid of what?
Variation
What is a panmictic population?
Chance for breeding with everybody else in a population.
Example of a panmictic population
Pupfish in Devil’s hole
What is a cline?
A cline refers to a spatial gradient in a specific, singular trait, rather than a gradient in a population as a whole. A single population can therefore theoretically have as many clines as it has traits.
What is an example of a cline?
The skull size of Deer changes with temerature
What is Bergmann’s rule?
Lager size species are found in colder environemnts
What is a pre-zygotic barrier?
Stops transfer of gametes before mating
What is post-zygotic barrier?
Produce offspring that is infertile
Example of pre-zygotic barrier
Booby birds will reject birds with different coloured feet
Why do hybrids not always work?
Unviable or sterile
What are the four types of how species form?
Allopatric
Peripatric
Parapatric
Sympatric
What is allopatric speciation?
Populations of the same species become isolated and form into a new species
Example of allopatric speciation?
Adaptive radiation with Darwin’s finches
What is peripatric speciation?
Closely related species in an isolated area
Example of peripatric speciation
Polar bear and brown bear
What is parapatric speciation?
Adjacent ranges with a narrow contact zone so species form in a new area
Example of parapatric speciaiton
Lizards.
evolution along a gradient
What is sympatric speciation?
Evolution of new species within the same habitat due to reproductive isolation
Example of sympatric speciation
Cichlid fish with different diets
What did Crook find about behavioural differences in Weaver birds?
Those in the forest were insectivorous and monogamous whereas the savannah-dwelling ones with granivorous and polygynous
What is an allopatric population?
Occurring in separate, non-overlapping areas
What is sympatric speciation?
Occurring within the same area
Genetic changes in a allopatric population can be caused by what?
genetic drift, divergent ecological or by sexual selection
When can sympatric speciation occur?
If disruptive selection favours preferences for different habitats
Example of sibling species
alder and willow flycatcher
What is needed for the development of a weapon?
- Defendable resource
- Competition
- One-on-one duel
