paleontology
study of past, study of fossil remains
how long has the earth been present for?
4.6 billion years
3 eras of geological past
-palaezoic (oldest)
-mesozoic
-caenozoic
when was the paleozoic era and what came out of it?
534 million years ago/beginning of Cambrian period, when all ancestors of modern animals arose
3 points of the mesozoic era
- triassic was the first period
- first dinosaurs, mammals, conifirs, cyads, and therapsids
- age of reptiles
3 ways to determine fossil age:
- relative dating: based on principle of superposition
- absolute dating: determined by testing fossil itself or material around it
- radiometric dating: MOST accurate, based on half-life or decay of isotope
5 kinds of fossil formation
- compression
- petrification
- impression
- cast
- preservation by sap
2 major continents developed after pangea
laurasia and gondwana
marsupials and examples
most abundant land mammal on earth, have pouch ex. kangaroos, koala, wombat, opossum
placentals
have a placenta, develop inside the human body, greater survival rate than marsupial
wallace’s line
boundary that separates Asian animals from Australian animals (between indonesian islands of bali and lombok)
Homologous structures
two structures that can share common ancestry but do not necessarily serve the same function (evidence based on anatomy)
Analogous structures
structures in different organisms that appear similar in function or form, but occured independently from one another
what is it called when analogous structures arise independently
convergent evolution
vestigial structure
structure that no longer functions but remains in diminished form
adaptative radiation
species diversify rapidly
Examples of homologous structures
fin of whale, hand of person, wing of bat
Analogous structures examples
winged animals: insects, birds, bats
Vestigial structures examples
pelvis in snakes and whales, leaves spines, humans: appendix, ear muscles, nictitating membrane, wisdom teeth, tailbone
