Evolution

theories of evolution

catastrophism: catastrophe wiped out a population

gradualism: effect slow but continuous progress

uniformitarianism: processes today have not evolved over history

Lamarck

So close award

first theory of evolution - inheritance of acquired characteristics, two forces

1. a force based on alchemy drove organisms up the ladder

2. another environmental force

   idea that species could change/transmutate

Darwin

no animal “higher” than other

all animals descended from common ancestor

organisms adapted to their environment, branched out from development through natural selection

work on the voyage of HMS Beagle - Galapagos notable

natural (& sexual) selection

favorable traits helped individuals survive and they pass that trait to their offspring

can cause two populations of same species to change drastically if they lived in different environments

sexual: changes in populations due to reproductive preferences

support for evolution/the common ancestor

natural and sexual selection, comparative anatomy and adaptations, comparative genomics, fossils, biogeography, speciation

comparative anatomy and adaptations

analogous features: different lineages but similar niches (ex: wings)

homologous features: same lineages but different niches (same structure, different function)

vestigial organs - organs that no longer function, may become smaller (ex: appendix)

adaptation as process vs. trait

process: organisms change over time to become more fit to their environment

trait: specific trait an organism has developed over time to survive in ecological niche

comparative genomics

all organisms have a genetic code

high degree of similarity in DNA in different species (sequence of ribosomes)

some genes (Hox) have same or similar functions across species, like embryonic development

phylogenetic trees

fossils

fossil records show development of complex organisms over millions of years

mass extinction of events (asteroid, volcano, methane from oceans)

radiometric dating - how much radioactive element a fossil has

stratigraphy - relative dating of fossil based on rock layer

geologic time

eons and eras of earth’s history

Paleozoic: cambrian explosion

mesozoic first vertebrate land animals + dinosaurs

Cenozoic: K-T event (asteroid, ¾ of plant and animal species)

first hominis by end of Cenozoic era

supercontinents

pangea: small super continents formed large land mass - broke up to gondwana and laurasia

post gondwana are Americas, Australia, India, Africa, Antaractica

India collided back with Asia

biogeography

how species have been distributed around the world

fossils, continental movement, and plate tectonics

species range - region on Earth that a particular species inhabits is called its range

dispersal - migration organisms and how biogeographical barriers influence their distribution