ASTR230 exam 4

prokaryote definition

no nucleus

eukaryote definition

yes nucleus

eukaryote endosymbioses

mitochondria

plants and algae endosymbioses

chloroplasts

stromatolite

a layered rock made of cyanobacteria

stromatolite formation

through microbial mats trap sediments, cyanobacteria photosynthesis and new layers forming repeatedly as the microbes grow upwards toward sunlight

Cambrian → ordovician → silurian → Devonian → carboniferous → permian

cuddly old camels make perfect pets

start of GOE

beginning of Proterozoic (~2.5Ga)

pandora gravity

lower than on earth ~80% of earths gravity

Pandora biology

bioluminescent plants are common as well as 6limbed animals.

Pandora chemistry

composition of atmosphere different to earths (Co2, xenon, H2S)

Pandora atmosphere

more toxic and dense , lots of CO2, xenon and H2S

what is life

order, reproduction, growth, development, energy, and evolutionary adaption

when does life start

the Hadean - Archean boundary

Miller Urey experiment

was able to mimic the earth earth environment to determine if precursors to life formed organic compounds.

What did miller urey experiment have

methane, ammonia, hydrogen and water + some light = amino acids

types of symmetry that life has

radial, bilateral, and chiral.

life sustaining energy?

geothermal energy, chemical energy from hydrothermal vents, and tidal heating

survival of the fittest

an organism that is best adapted to its environment is able to reproduce, this is merely dependent on the environment and an organism to adapt.

surviving beneficial mutations through natural selection

the individual must actually survive long enough to reproduce and pass on the gene to their offspring for natural selection to work

how were there multicellular life before the Cambrian

they mainly had hard body parts which made it easier for them to fossilize and the increased oxygen levels during the Ediacaran period supported larger more active organisms

what HELPED the cambrian multicellular life

the breakup of supercontinents and associated changes in the oceans chemistry + oxygenation and nutrient availability mainly led to precipitating the adaption

why did the cambrian happen in shallow seas

because rising sea levels flooded continental landmasses. one of the landmasses resulted ina. new habitat environment rich with nutrients + sunlight

What is cladistics

A classification system based on shared derived traits and common ancestry.li

why liver big?

because it serves as our bodys detoxification and metabolic processing center.

What do branches on a phylogenetic tree represent?

Clades—groups with a common ancestor and all its descendants

What caused the Permian–Triassic extinction?

Massive Siberian Traps volcanic eruptions causing greenhouse effects, ocean anoxia, and massive hydrogen sulfde release which led to an ecosystem collapse

What caused the Cretaceous–Tertiary (K–T) extinction

by the effects of chixlux aesteroid impact in mexico that was large enough to kick up a massive dust cloud that blocked sunlight triggering a global winter and disrupting photosynthesis which ultimately destroyed the ecosystem and led to many taxa becoming extinct like dinosaurs

Why do we focus on multicellular extinctions, not bacteria?

Bacteria evolve much faster and recover quickly.

What are natural threats to civilizations?

Asteroids, volcanoes, storms, pandemics

What are human-caused threats to civilizations

Climate change, nuclear war, bio-weapons, resource depletion.

What are signs of intelligence

Tool use, communication, culture, abstract thought, flexible problem solving

Why do we search for radio signals for intelligent life?

Radio travels far through space and is energy-efficient

What is the Fermi Paradox?

If life is likely, why haven’t we seen any evidence?

N

number of civilizations per galaxy

R

star formation rate

Fp

Fraction of stars with planets

nE

fraction of earth like planets

fL

Fraction that developed life

fi

fraction that developed intelligent life

fc

fraction that developed radio communication

L

average lifetime of a civilization