topic 9

Question 1

features that define life

Answer 1

organization (one or more cells), metabolism, response to stimuli, homeostasis, adaptation, reproduction

Question 2

are viruses alive

Answer 2

ish. they lack metabolism/homeostasis and cannot reproduce outside of a host cell

Question 3

eons of the geologic record

Answer 3

archaean, proterozoic, phanerozoic (precambrian = archeaen/proterozoic)

Question 4

eras of the phanerozoic eon

Answer 4

paleozoic, mesozoic, cenozoic

Question 5

how are boundaries between geologic definitions made

Answer 5

mass extinction events from the fossil record

Question 6

what are fosssils

Answer 6

preserved remains/evidence of past organisms, often found in sedimentary rock

Question 7

rock strata

Answer 7

distinct layers of rock

Question 8

what are fossils used for

Answer 8

calibrate phylogenies, record extinct species, link evolutionary events

Question 9

why is the fossil record biased and incomplete

Answer 9

requres burial in sediment, often only hard parts preserved, most organisms were never fossilized

Question 10

what increases the probability of fossilization

Answer 10

existed for a long time, abundant/widespread, hard bodied, aquatic, inshore marine, absent of decomposing organism

Question 11

mold fossils

Answer 11

hollow space/impression eft my the organism

Question 12

cast fossil

Answer 12

minerals fill the mold –> solid replica

Question 13

replacement/petrified fossils

Answer 13

original tissues replaced by minerals (preserves detailed structure)

Question 14

trace fossils

Answer 14

behavioral evidence (tracks, burrows, feces)

Question 15

preserved possils

Answer 15

carbon films/amber/tar/peat/frozen that retain a lot of organic material

Question 16

how does relative dating work

Answer 16

sedimentary strata reveal how old they are relative to eachother

Question 17

issues with relative dating

Answer 17

leaves gaps, sediments can move around (overcome through indicator fossils)

Question 18

absolute/radiometric dating

Answer 18

radiactive decay of isotopes provides an absolute age for the fossil, based off of its half-life

Question 19

plate tectonics theory

Answer 19

the earths crust has large plates that have been slowly moving since 3.4 ba –> continental drift

Question 20

results of continental drift

Answer 20

tectonic plates collide/slide/separate, forming mountains, islands, earthquakes

Question 21

continental druft during the phanerozoic eon

Answer 21

alterations of physical geography and climate: fomration of pangaea leading to cooler/drier/deeper, impacting biodiversity through opportunities for diversification/speciation, mass extinctions,

Question 22

gondwana

Answer 22

paleo-continent of australia, antartica, s america having similar fossi

Question 23

continental drift and biodiversity

Answer 23

diversitification when land masses are isolated, mass extinctions as climates change

Question 24

permian mass extinction

Answer 24

between paleozoic and mesozoic eras (252ma), most servere extinction event, the great dying, caused by volcanic activity (or gradual changes)

Question 25

cretaceous mass extinction

Answer 25

between mesozoic and cenozoic, 66ma, coincides with meteorite deposites --> impact-cause extinciton

Question 26

holocene extinction

Answer 26

sixth, human-caused extinction, rapid decrease in biodiversity

Question 27

consequences of mass extinctions

Answer 27

takes a long time to recover biodiversity, changes types of organisms in communities, can wipe entire lineages, adaptive radiation

Question 28

adaptive radiation

Answer 28

rapid evolution of diversely adaped species from ancestral species (new niches available)

Question 29

causes of adaptive radiation

Answer 29

mass extinctions, evolution of new characteristics, colonization of new regions

Question 30

early earth

Answer 30

formed 4.6bya during hadean eon, very hostile for 1st by, thin crust on unstable magma, atmosphere without oxygen, water vapour as earth cooled, atmosphere of volcanic cases

Question 31

how did life begin

Answer 31

abiotic synthesis of small organic molecules, polymerization, formation of protocells, emergence of self-replicating molecules

Question 32

abiotic synthesis of small organic molecules

Answer 32

formation of basic organic compounds through abiotic proesses: spontaneous terrestrial origins or extraterrestrial impacts, likely near volcanoes or deep hyrothermal vents

Question 33

miller-urey experiments

Answer 33

demonstrations that organic molecules can be produced spontaneously in reducing and non-reducing environments

Question 34

polymerization into organic polymers

Answer 34

small organi molecules forming larger organic molecuels, likely on hot surfaces where evaporation of water triggered spontaneous formation of organic polymers

Question 35

formation of protocells

Answer 35

lipids form a hollow vesicle (faster in volcanic clay), simple reproduction/metabolism, maintain an internal chemical environment

Question 36

emergence of self replicating molecules

Answer 36

molecules that can store and transmit infomration (rna, dna), self replication to pass on information

Question 37

catalysis

Answer 37

some rnas (ribosomes) act like enzymes inself-replicating molecules to speed up reactions

Question 38

prokaryotes

Answer 38

oldest fossil evidence of life: unicellular, uncontained dna, organelles not membrane-bound, bacteria/archaea

Question 39

stromalolites

Answer 39

oldest known fossils, accumulation of sedimentary layers on prokaryote mats

Question 40

the great oxygenation event

Answer 40

when oxygen began accumulated in atmosphere and oceans, oceanic photosynthetic prokaryotes (cyanobacteria) evolved to use the sun's energy, producing o2 --> ocean saturation and eventual atmospheric oxygen

Question 41

results of the goe

Answer 41

extinction of many prokaryotic groups (end of archean eon) because o2 was toxic to anaerobic prokaryotes, those that surived evolved aerobic respiration