Chapter 4.3 Flashcards
What can biological species that are isolated not do?
Interbreed
What does reproductively isolated mean?
When biological species can not interbreed. ex. Frogs and Elephants
What would populations that breed during different time periods be known as?
Reproductively Isolated
What is Speciation?
The formation of new species
What are the two methods of Speciation?
Transformation and Divergence
What is transformation?
When a new species gradually develops as a result of mutation and adaptation to changing environmental conditions and the old species is gradually replaced
What would happen if Speciation only happened through Transformation?
The total number of diversity would remain unchanged
What is Divergence?
When one or more species arise from a parent species that continues to exist
What are the pathways to Speciation a result of?
Natural Selection
What must happen for speciation to occur?
The populations must be prevented from interbreeding. (Become isolated)
What happens so that Speciation occurs?
Populations of the same species are isolated from one another. Due to natural selection changes form and this affects reproduction. The two populations are no longer compatible
What can keep species isolated from one another?
Geographical Barriers
Biological Barriers
How do Geological Barriers isolate species?
Barriers such as mountains and rivers keep species physically separated. It does not have to remain forever only long enough for them to not be reproductively compatible
How do biological barriers isolate species?
Behavior can keep species isolated. ex. different species have different mating calls
How can Speciation occur in population that aren’t already reproductively isolated populations?
They become reproductively isolated by using different resources
What is Adaptive Radiation?
The diversification of a common ancestral species into a variety of species, all of which are differently adapted
What are the 2 models that scientist have proposed for the pace of evolution?
Gradualism and Punctuated Eqilibrium
What does the model of Gradualism say?
Gradual changes occur steadily in a linear fashion. Big changes are the result of many small changes
What does Punctuated Equilibrium say?
Evolutionary history consists of long periods of equilibrium where there is little change interrupted by periods of speciation
What are the ideas in the theory of evolution by natural selection?
- Life forms have developed from ancestral species
- All living things are related to one another by varying degrees through common descent
- All living things on earth share a common ancestor
- The mechanism for speciation includes random genetic mutations and natural selection
