chapter 25: ap bio

how did life arise? 1

small organic molecules were synthesized (ex. amino acids and nitrogenous bases)

how did life arise? 2

small molecules polymerized into macromolecules (ex. proteins and nucleic acids)

how did life arise? 3

molecules packaged into protocells

protocells

membrane-containing droplets

how did life arise? 4

self-replicating molecules allow for inheritance (RNA)

ribozyme

first RNA catalysts

when did earth form?

4.6 billion years ago

what did earth's early atmosphere contain?

water vaper and chemicals released by volcanic eruptions, such as nitrogen, nitrogen oxides, carbon dioxide, methane, ammonia, hydrogeb, hydrogen sulfide)

oparin and haldane

hypothesized a reducing environment

miller and urey

lab experiments proved the abiotic synthesis of organic molecules (like amino acids)

alternative theory 1

first organic compounds were synthesized near volcanoes or deep-sea vents

small organic molecules would polymerize when

concentrated on hot sand, clay, rock

what can lipids do in water?

form vesicles with a lipid bilayer

the first genetic material was?

RNA, not DNA

ribozymes do what?

make complementary copies of short stretches of RNA

the first living organisms have been documented

3.5 billion years ago

3.5 bya there was no

oxygen

when did oxygen appear?

2.7 billion years ago

what allowed for the production of oxygen?

cyanobacteria would undergo photosynthesis

what is strata?

layers of rock

incomplete record

many organisms not preserved, fossils destroyed, or not yet found

fossil record is biased towards

existed for a long time, abundant, widespread, had hard parts

radiomentric dating

a way to find the age of fossil using the half-life

half-life

the time required for half the parent isotope to decay

relative dating

uses order of rock strata to determine the relative age of fossils

each era ends and starts with

ends with major extinction and starts with adaptiove radiation

timeline

3.5 bya - first prokaryotes

2.7 bya - oxygen in atmosphere

2.1 bya - first eukaryotes

1.2 - first multicellular eukaryotes

500 mya - colonization of land

stromalites

the oldest fossil- rocks formed by the aaccumulation of sedimentary layers on bacterial mats

banded iron formations

oxygen that reacted with dissolved iron and precipitated out to form

oxygen revolution

caused the extinction of many prokaryotic groups

endosymbiont theory

mitochondria and chloroplasts were formerly small prokaryotes living within larger host cells

cambrian explosion

the sudden appearance of fossils resembling modern animal phyla

plants and fungi

mutually beneficial and likely colonized land together

the rise and fall of groups depend on

speciation and extinction rates within the group

plate tectonics

earth's crust is composed of plates floating on earth's mantle

interactions between plates cause

the formation of mountains and islands, and earthquakes

the distribution of fossils and living groups reflects

the movement of continents

mass extinction

a large extinction of species in a relatively short period of time

factors that contribute to mass extinctions

volcanoes, glocal warming, redcued temperature gradient, reduced mixing of ocean waters

alternative theory 2

organic molecules could have been transported to earth by a meteorite

adaptive radiation

evolution from a common ancestor of many species adapted to diverse environments

adaptive radiation may follow

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

heterochrony

evolutionary change in the timing or rate of an organism's development

heterochrony examples

human and chimpanzee skulls

paedomorphosis

the rate of reproductive development accelerates compared with somatic development

homeotic genes

genes that determine basic features of where a body part is

homeotic gene example

wings on a bird

hox genes

class of homeotic genes. changes in these genes can have a profound impact on morphology

exaptations

structures that evolve in one context but become co-opted for another function