chapter 1
Hadean Eon
4.6-4.0 bya
Earth was molten ball, too hot for any life
Archaea Eon
4.0 - 2.5 bya
earth cooling
first life appears as unicellular prokaryotes
Proterozoic Eon
2.5 bya - 541 mya
first multicellular life appears
first eukaryotes
first photosynthetic organisms
the boring billion where the eukaryotes diversified
snowball earth - the ice age - early diversification of animals
first world wide large bodied animals
Phanerozoic Eon
541 mya - now
rapid diversification of animals
colonization by plants and animals
explosion of life
how many eons are there
4
how many eras in the phanerozoic
3
Paleozoic era
541- 252 mya
in the phanerozoic eon
6 periods
Cambrian period
541-252
Cambrian explosion - big bang of life - sudden radiation of complex life
in the paleozoic era
in phanerozoic eon
Ordovician Period
485-444 mya
diversification of marine animals
in the paleozoic era
in phanerozoic eon
Silurian Period
444-419 mya
array of fish in the ocean
in the paleozoic era
in phanerozoic eon
Devonian period
419-359 mya
tetrapods emerge and amphibians climb on land
in the paleozoic era
in the phanerozoic eon
Carboniferous Period
359-299 mya
large reptiles
in the Paleozoic era
phanerozoic eon
Permian Period
299-252 mya
biggest mass extinction caused by rapid global warming
paleozoic era
phanerozoic eon
mesozoic era
252-66 mya
dinosaurs, sea plants, flowering plants, birds, mammals
ended by mass extinction
phanerozoic eon
3 periods
Triassic period
252-201 mya
in the mesozoic era
phanerozoic eon
Jurassic Period
201 - 145 mya
mesozoic era
phanerozoic eon
Cretaceous Period
145-66 mya
mesozoic era
phanerozoic eon
Cenozoic Era
66 mya- now
radiation of mammals primates and whales
3 periods
phanerozoic eon
paleogene period
66-23 mya
cenozoic era
phanerozoic eon
neogene period
23-2,6 mya
cenozoic era
phanerozoic eon
quaternary period
2.6 mya - now
rise of the homo species
Cenozoic era
phanerozoic eon
how many periods in the cenozoic era
3
how many periods in the mesozoic era
3
how many periods in the paleozoic era
6
Essentialism
- the view that the variable phenomena of nature is derived from a limited number of constant essences
- prevented the idea of evolution for a long time
- the essence is eternal permanent and unalterable
- any variations are mistakes rather than improvements
Plato's cave allegory
suggests we cant observe essence directly but rather the reflections or shadows of the real things
essentialism leads to
typological thinking
Typological Thinking
things are categorized as types and ignores individual differences
emphasis on the shared properties of organisms
assigns stereotypes to individuals
Who developed Population thinking
Darwin
How does typological thinking view variation
As a mistake, disregards it
population thinking
while still acknowledging similarities, scientists pay attention to variability across individuals and species
emphasizes the properties of individual over generalization of species
type specimen
an anachronism non representative of population thinking and the variability of species
derived from typological thinking