Origin of species

Question 1

what is NASA’s definition of life

Answer 1

any sytem that shows Darwinian evolutiomn

Question 2

what is the theory for the origin of energy that fueled the first replicating molecules

Answer 2

Deep sea 3.8 billion yrs ago
proton gradients created from alkaline hydrothermal vents
(‘aka the lost city’)
found near tectonic plates

Formed ATP
Energy from the ion gradients is used to phosphorylate atp

Question 3

why is RNA a possible contendor for the origin of life?

Answer 3

• can replicate itself
• acts like an enzyme
• complex organic molecules are produced by organic chem
• one of which ended up being RNA
• which started to assemble proteins
• amino acids started to appear ^
• in turn created DNA –> LUCA (last universal common ancestor, single celled organism)

but because it’s so fragile - needs cell

Question 4

why did DNA outcompete RNA at this time

Answer 4

• more resistant to UV
• more stable
• replicated faster, more efficient -> checked for errors

Question 5

how does the RNA world show proof that evolution into complex organisms wasn’t intended

Answer 5

for 2B yrs, everything stayed the same
as single celled organisms
other than the ability of photosynthesis that develpoed during this time
everything else was pretty boring

Question 6

what were the first ‘cell-like’ structures used to protect DNA

Answer 6

lipid protobionts
they can reproduce and metabolise

Question 7

timeline of origins of the universe and life

Answer 7

unieverse: 14 billion yrs ago
earth: 4.5B yrs ago (darwin acc thought it was 10M yrs old and was worried there was no time for his theory to have taken place)
life: 3.8B yrs ago?

Question 8

what is needed for life

Answer 8

cool temp
gravity
water
protection from radiation

as soon as the conditions were ready on Earth, life appeared

Question 9

Great oxidation event

Answer 9

• first prokaryotes were methane producing bacteria
• cyanobacteria (blue-green algae) produce O2 = photosynthesis
• O2 consumed by methanogenic bacteria

but then most methanogens die out

Question 10

eukaryote key features

Answer 10

nucleus,
mitochondria
chloroplasts in plants
golgi bodies
sex
phagocytosis

outnumbered by prokaryotes, but indicidual cells can be up to 1,000,000x bigger than prokaryote volume

some are mulitcellular, most are unicellular

Question 11

eukrayogenesis

Answer 11

archaebacterium engulfed a heterotrophic eubacterum = eventually became mitochondria

energy from mitochondria allows large complex life

Question 12

ring of life

Answer 12

see diagram in onenote

Question 13

dickinsonia

Answer 13

molecules from rock, found to be animal in origin
had bits of cholesterol in it

Question 14

the cambrian explosion: when and causes

Answer 14

540-515 M yrs ago

most types of animals first appear in fossil record

causes:
- physiological change: dissolved O2 allowed more active lifestyle
- geographical change: new seas, warm seas = faster movement etc.
- geochemical change: sea level changes lead to abundace of trace metals = exoskeletons
- biological change = inc in zooplankton -> new predators arise -> inc selection pressure

• disappearance of dinos left ecological space for mammals and birds

Question 15

how long does an ecosystem take to recover from mass extinction

Answer 15

~20M yrs

Question 16

Permian extinction

Answer 16

95% of all sea life
70% of families of land animals became extinct

• could be cause of volcanism, tectonic plate, asteroid etc
• allowed for expansion of diaspids -> dinos
• theraspids survived (our ancestors)