Macroevolution (Speciation)

macroevolution

results in speciation, extinction, and evolution of major new features of living things

speciation

origin of new species

hybrid

• offspring of two diff species

• infertile

biological species concept

• group of individuals able to breed w each other and produce fertile offspring

• this definition is limited to sexually-reproducing and living species

first step of speciation

separation of small splinter population

what are the two possibilities when a group is separated from population

• separated population follows own evolutionary course and becomes less and less like og population

• separated population dies from new, harsh environment

reproductive isolation

inability of two organisms to reproduce due to some barrier

geographic barrier aka

allopatric speciation

what are the geographical barriers

geographical isolation and habitat isolation

geographical isolation

• geologic process separates population

  • ex. mountain

• founder effect

  • ex. island

habitat isolation

species living in same area adapt to diff habitats and have habitat preferences

non geographical barrier aka

sympatric speciation

prezygotic barriers

temporal, behavioural, mechanical, gametic

post-zygotic barriers

hybrid inviability and hybrid infertility

temporal isolation

different breeding seasons

behavioural isolation

different mating rituals

mechanical isolation

reproductive structures physically incompatible

gametic isolation

• different sex cells

• markers dont match up

hybrid inviability

unhealthy hybrid

hybrid infertility

infertile hybrid

adaptive radiation

• evolution from common ancestor that results in diff species adapted to diff environments

• aka divergent evolution

how does adaptive radiation occur

from allopatric speciation (geographical barriers)

convergent evolution

process whereby organisms arent closely related, but independently evolve similar traits due to having to adapt to similar environments

how do humans affect diversity

introduction of invasive species and pollution

ecological niche

environmental conditions and resources used, role in ecosystem