Changes In Biodiversity Over Time Flashcards
(34 cards)
What are 4 main conditions required for fossilization?
Rapid burial, slow decomposition, further burial, left undisturbed
What did animals walk on land?
440-410 mya
When did mammals first appear?
160 mya
when did flowering plants first appear?
130 mya
When did multicellular organisms begin to appear?
600 mya
What are trace fossils?
fossils that show evidence of the existence of an organism, like a footprint
What are mould fossils?
Fossilized impressions of remains imprinted on rock
What are cast fossils
Mould fossils that have been filled in by minerals
What is the half-life of carbon 14?
5730 years
How old do fossils have to be to for carbon dating to be used?
less than 50,000 years
How does carbon dating work?
Carbon 14 isotope decays at a known rate to the more stable nitrogen 14. The ratio of C12: C14 is measured in fossils and then used to determine the age of the fossils based on carbon 14s half-life.
What is potassium dating best used for and why?
very old fossils, as potassium 40 has a half-life of 1.25 billion years
What does potassium 40 decay to?
Argon 40
What is the difference between absolute and relative dating techniques?
Absolute dating techniques give an exact age of the fossil whereas relative dating techniques give an age of a fossil relative to other fossils.
What are index fossils?
Fossils of species that are known to have lived within
a specific and short time period
Why are index fossils useful?
They enable you to compare fossils of known age to those of unknown to get a relative age
What is stratigraphy?
Estimating rock age, based on rock layer position
What are homologous structures?
Features in different species with different functions but the same structure
What are analogous structures?
Features in different species with the same function but the different structure
What do homologous structures show?
that the organisms shared a recent common ancestor (divergent evolution)
What do analogous structures show?
that environment impacts evolution. (convergent evolution)
What are vestigial structures?
structures in a species that had a function in an ancestor but have little function in the current organism
What does developmental biology show?
That when there are similarities between different species embryo’s they share a similar developmental gene and hence have a recent common ancestor
What occurs during convergent evolution?
When 2 species which different common ancestors develop similar traits as a result of similar selection pressures
