Life Over Time and Mass Extinctions Flashcards
(44 cards)
Why are plants and animals in India different than Southeast Asia?
India was its own continent until 45 million years ago
Angiosperm
flowering plant
Gondwana
Ancient supercontinent that consists of Africa, South America, Australia, Antartica, India, and the Arabian Peninsula
How do lizard species on mainland California compare in diversity to those found on islands?
Due to greater ecological opportunities on islands, there is greater differences between island species
What is exceptional about the early animal faunas from the Ediacaran period just before the Cambrian?
soft-bodied animals are well represented by these fossils
soft bodied fossils are rare
Key innovation (evolutionary innovation)
a novel phenotypic trait that allows subsequent success of a taxonomic group
Does genetic drift directly cause adaptive radiation?
No
Can an unusual event splitting a habitat, such as a hurricane led to adaptive radiation?
No
When did Pangea occur?
Late Paleozoic and early Mesozoic era
What major evolutionary episode corresponded the closest with the formation of Pangea?
Permian extinctions
How do fossils start to form?
Start with burial in sediment
Intact fossil
forms when decomposition does not occur and the organic remains are preserved intact
Compression fossil
forms when sediments accumulate on top of the organism and become cemented into rocks such as mudstone or shale
the sediments weight compresses the organic material below into a thin, carbonaceous film
Cast fossil
forms when organisms decompose after they are buried
the hole that remains fills with dissolved minerals, which creates an accurate cast of the remains
Permineralized fossil
forms when organisms decompose extremely slowly
Trace fossil
forms when sedimentation and mineralization preserve indirect evidence of an organism in the environment
ex: footprints, tracks, feces
Conditions for fossils to occur
- buried rapidly
2. decompose slowly
Habitat bias
Organisms that live in areas where sediments are actively being depositing (beaches, swamps) are much more likely to form fossils than are organisms that live in other habitats
Taxonomic and Tissue Bias
Organisms with hard parts, such as bones or shells, are most likely to leave fossil evidence
similar idea applies with tissues
Temporal bias
Recent fossils are much more common than ancient fossils
The older a fossil is, the longer it has been exposed to destructive forces
Abundance bias
fossil record is weighted towards common species
Paleontologists
scientists who study fossils
Why is it hard to estimate when species first appeared in the fossil record?
A particular species or lineage can exist for millions of years before leaving fossil evidence
Precambrian
Interval between the formation of the earth and the appearance of most animals (541 bya)
Unicellular
Oxygen was virtually absent until photosynthetic bacteria
