Life on Earth Flashcards

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1
Q

what are the four main eras of earth’s history

A

Phanerozoic
Proterozoic
Archean
Hadean

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2
Q

Phanerozoic era length

A

present- 500 MYA

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3
Q

Proterozoic era length

A

500 - 2500 MYA

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4
Q

Hadean era length

A

3800 - 4600 MYA

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5
Q

Archean era length

A

2500 - 3800 MYA

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5
Q

explain the Archean era

A

planet cooled slightly, releasing water vapour from rocks, first life emerged (prokaryotes)

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6
Q

explain the Hadean era

A

volatile earth, comes from hades greek god of hell, lots of toxic gases and acids,

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7
Q

how did life begin? (4)

A

simple organic molecules -> replicating molecules -> natural selection and evolution

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8
Q

what role mineral rich oceanic chimneys have in the evolutionary beginnings of earth’s basic life forms

A

mineral rich chimneys - chemical reactions between hydrogen and carbon dioxide form complex organic compounds

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9
Q

key features of prokaryotic organisms ( basic shit ik but u better remember this shit spastic)

A

prokaryotes evolved from protocells (not a key feature but still important)

single-celled
no nucleus (nucleoid - DNA ring)
no organelles
Thylakoid membranes - photosynthesis

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10
Q

what are oldest organisms on earth

A

stromatolites, hard structures consisting of cyanobacteria bound with sediments,

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11
Q

explain the Proterozoic era

A

eukaryotes came in

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12
Q

how did eukaryotes evolve

A

the theory of endosymbiosis

ancestrial eukaryotic cell + aerobic bacterium = animal cell lineage (wherein the aerobic bacterium became the mitochondria)

ancestrial eukaryotic cell + cyanobacterium = plant cell lineage (where in the cyanobacterium became the chloroplast)

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13
Q

why did the evolution of multicellularity occur? (4)

A

cells evolved aggregation

to avoid predation
functional specialisation
integration of environmental cues

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14
Q

explain the Phanerozoic era

A
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15
Q

Cambrian explosion

A

Trilobites: earliest arthropods (=insects,
arachnids, crustaceans)
20,000 species (most common fossils in
Cambrian rocks)
Evolved exoskeletons within a few million
years
Nutrients from continental erosion
increased food web complexity (predator-
prey arms race)

16
Q

emergence of land plants

A

Early land plants had rudimentary pores and
lacked roots
Increase in mudrock associated with increase in
early land plants
Land plants released phosphate
Food chains

17
Q

tetrapod evolution

A

paired fins of fishes have bones that are homologous (similar structures with same evolutionary origin)

18
Q

global distribution of flowering plants

A

higher diversification rates in dry land areas than in tropics

19
Q

permian-triassic extinction

A
20
Q

Cretaceous-Tertiary KT (Paleogene) extinction

A

Massive asteroid hit Yucatan peninsula (Mexico)
75% of al plants and animals lost
Nearlv all dinosaurs and many Invertebrates
became extinct (e
*g., ammonolas
Al tetrapods > 25kg became extinct
Onlv lines of archosaurs to survive became moderr
birds and crocodiles

21
Q

what shapes animal colouration

A

social environment, ecological interaction, physical environment

these all act as external stimuli

22
Q

what is the point of animal colouration

A

mate attraction
social signalling
territory defence
camouflage

23
Q

stripes pattern function

A

breaks up outline of body
distorts animals speed
deter biting flies

24
Q

spots pattern function

A

draw attacks to less-vital body areas
mimic predator’s eyes