history of life on earth Flashcards
(23 cards)
what are the major event sin earths history
-big bang: formation of earth. elements congealed into earth.
-haedan earth: hot and non liveable
whats the hypothesis for the origin of life
-abiogenesies: living organisms arose from inorganic compounds. This is believed to arise from the primordial soup which is full of organic molecules that is being concentrated. this is backed by the miller Urey experiment. another is the hydrothermal vents
- panspermia/exogenesis: the hypothesis that life originated elsewhere in the universe and came to earth via asteroids, comets etc.
what is the miler Urey experiment
able to synthesise building blocks of life
explain what is hydrothermal vents
life came around from hydrothermal vents spewing superheated water rich in minerals.
what is the importance of evolution
enzymes are essential as the building block in life. they wanted to synthesis panthetheine because this is what you need to get a metabolism.
explain what LUCA is
this is the last universal common ancestor. this doenst say that life only started once. we know everything since related because we all use the same genetic codes. first evidence is stromatolites.
how was life before the great oxygenation event
earth athmospehre lacked oxygen so most living organisms where anaerobic. evolution of cynobacterium arose. its byproduct is oxygen and because there was so much of them, it increased the oxygen in the earths atmosphere.
huronian glaciation
believed to have great oxygenation of life. massive change in composition of atmosphere and climate
when did evolution of eukaryotic cells happen
after the great oxygenation event. believed to be a prerequisite for complex multicellular life.
what is endosymbiosis
theory for how mitochondria formed in cells. two independent bacteria where one attempt to eat the other but the process halts and they just live together. they have a symbiotic relationship and became inseparable
what does multicellularity require
-complex development
- coordination among cells
-cellular specialisation
some lineage have multicellular and unicellular species. it is believed that multicellularity evolved many times- replicated in lab yeast evolved to be more sticky and specialised- if selection pressure is there, multicellularity is possible from eukaryote
what is ediacatrian fauna
first animals able to move. diversifaition of complex multicellular organisms. there are a number of organisms that can be assigned to modern groups
what is the Cambrian explosion
first sign of most modern groups of animals appeared like the phylums we have now. - most evidence is in mount burgess in Canada. biological diversity occurred here but the reasoning behind it is unclear- some say its increase in oxygen, chemistry
ordovician, silurian and Devonian
we see the first fish- known as age of fishes or marine life
how many mass extinctions where there
5.
what is carboniferous
plants colonised the land and insects diversify
why do insects during carboniferous so big
high oxygen levels because insects respiratory system relies on diffusion
famous march of progress
picture of how we evolved
have we always been the only homosapiens
we shared the same planet with 9 other homo species. we interbred with at least three:
1. Denisovans
2.neanderthals
3. mystery hominin
what is continental drift
-pangaea everything is connected
- laurasai and gondwana:
- modern world
what did the continental drift do
resulted to Gondwanan legacy
what is the gondawanan legacy
birds that look the same because they share the same ancestor during the Gondwana and laurasia land. as we experience continental drift, species began to separate and diversify on their own.
explain the Wallace line
a boundary that separates the ecozone of Asia and Australasian ecozone- animals that look the same but completely different. arose from gondwana and laurasia
