3. History of Earth Flashcards
what are the three domains of life
bacteria
eukaryotes
archaea
what are the six kingdoms of life
archaebacteria eubacteria protists fungi plantae Animalia
describe archaebacteria
these are prokaryotes with no peptidoglycan cell wall
eg halophiles
describe eubacteria
prokaryotes with a peptidoglycan cell wall
eg cyanobacteria
describe protists
eukaryotic unicellular organisms
describe fungi
multicellular eukaryotes with chitin cell walls
how old is the earth
4.5bn years
describe the early earth
very hostile, hot temperatures, reducing atmosphere, enabled formation of carbon rich compounds
what caused the rise of atmospheric oxygen
stormatalites- colonies of cyanobacteria which produce oxygen via photosynthesis
what was the consequence of the rise of atmospheric oxygen
why was this good
interacted with sunlight forming the ozone layer-
protecting the earth from harmful radiation
how did eukaryotes originate
what did this result in
an ancestral prokaryote
the plasma membrane folded allowing other aerobic heterotrophic prokaryotes to be engulfed
resulting in a endosymbiotic relationship between bacteria
how did multicellular eukaryotes originate
evolved from single celled eukaryotes
development of specialised cells
sexual reproduction well developed
when was the land colonised by plants/ animals/ fungi
500million years ago
what was the effect of the K-T asteroid impact
dinosaur extinction
-threw sulphur dioxide up into the atmosphere causing an ice age
what did the asteroid create
‘ecological space’ allowing other organisms to evolve freely without much competition
