Biology- Patterns of Evolution

Question 1

Divergent Evolution

Answer 1

initially similar populations accumulate differences over time to become increasingly distinct (large-scale evolution of a group into many different forms); likely due to geographic isolation (new niches)

• New species can evolve until all niches are filled
• Expect to see some similarities in descendants that connect them to each other and ancestor (e.g. homologous and vestigial features)
• E.g. groups of cats from one common ancestor (domestic cat, lions, tigers, cougars, jaguar, leopard, lynx, etc.),

Question 2

Adaptive Radiation

Answer 2

single species rapidly evolves into many distinct, but closely related species, with each differing to varying degrees from original ancestor and exploiting unique niches

• A type of divergent evolution
• Occurs when environment changes new niches available

Question 3

Convergent Evolution

Answer 3

the evolution of similar traits in distantly related species (no recent ancestor to pass on similar trait)  same structure or function evolves in different species because each experienced the same type of environmental pressures

• Environment may favour evolution of similar traits (analogous features) in similar environments
• Other features will indicate their distinct evolutionary past
• E.g. sharks and dolphins (both streamlined bodies, sharks from cartilaginous fish and side-to-side swimming, and dolphins with skeletons and up-and-down motion)
• E.g. bats, eagles and pterosaurs (flight

Question 4

Co-Evolution

Answer 4

• one species evolves in response to the evolution of another species (evolutionary success of one species is linked to another)
• E.g. parasite and host, plant and pollinator, predator and prey
• Can lead to heavy dependence upon one another, possibly affecting the survival of both is one is threatened