life science revice Flashcards
what is continental drift
movement of continental plates together or apart from each other
when all continents where all together being a big land is called a
pangean
studies from the past are called
biogeography
what is a fossil
and how are they preserved
the remains of ancient life forms
by rocks ,tar and ice
how long did the cambrain explosion last
the period lasted for 38 million years
when did the major groups of animals appear
5 to 20 million years ago of the cambrian period
the epoch we live in is called the
Holocene epoch
what are the appeared organisms through the end of the cambrain times
mammals~150 millon years ago
humans~150 -200 thousand years ago
fish~438 million years ago
the first bipedal animals of humans
appeared 2 million years ago
what does bipedal mean
animals that walked on two legs
what is extinction
death of all members of a certain species
what is mass extinction
when 50% of earths species die in a short period of time
What are the five major extinctions
439 MYA had a drop in sea levels
364 MYA causes unknown
250 MYA comet or asteroid impact or volcanic floods
299-214 Global warming
65 MYA asteroid impact on yucantan
two major extinction
250 MYA [90%]
65 MYA [all dinosaurs
the three main hypothesis
asteroid of other space
continets moving away from each other
volcanic eruption
