Unit 7 chp 23 notes Cheat Sheet by katiefocht

-Macroevolution

the broad pattern of evolution above the species level

-example: emergence of terrestrial vertebrates

major periods in earth’s history END with mass extinctions and new ones BEGIN with adaptive radiations!

– mass extinctions can alter ecological communities

evolutionary change in the rate or timing of developmental events

changes in morphology can also occur when there is a change in the sequence of developmental genes

example: stickleback fish

the gene is the same, but is expressed differently in the 2 groups of fish

provides glimpses of evolution over billions of years

-early: earth’s sols inhabitants were prokaryotic cells at least 3.5 billion years ago

-they transformed life on our planet!

-periods of evolutionary change in which groups of organisms form many new species whose adaptations allow them to fill different niches in their environment

diversity of life fueled by adaptive radiation

– one type hox genes provide positional information in an animal embryo

-small changes in regulatory sequences of particular genes can lead to major changes in body form

evolution is the result of the interactions between organisms and their current environments

help to give us a perspective when discussing events in the contexts of geological record

did not evolve until another 2 billions years of evolution of prokaryotes

1.5 billion years ago

evo-devo: research at the interface between evolutionary biology and developmental biology

-devlopmental genes guide the formation of the body from to adult. Even a small change in rate, timing, and spatial pattern can produce major morphological differences

an evolutionary trend does not mean that evolution is goal-oriented

surviving species do not represent the peak of perfection. there is compromise and random chance involved as well