History of life Flashcards
Fossil – physical evidence from an organism that lived in the past. Fossils provide the only direct evidence about:
what organisms looked like, where they lived (habitat), when they lived (how old they are), some information on how they lived.
Define fossil record
the total collection of fossils that have been found throughout the world.
name the limitations of the fossil record.
- anything that doesn’t live by water or are mostly made of tissue wont fossilize
____________ – organisms that live in areas with active sediment deposition more likely to be fossilized (e.g., beaches, wetlands)
habitat bias
_____________ – organisms with hard parts (e.g., bones, shells) or tissues with tough layers (e.g., pollen) are more likely to decay slowly.
Taxonomic & tissue bias
___________ – recent fossils are more common than ancient fossils.
Temporal bias
____________ – organisms that were abundant, widespread URQUHART, and present for a long time are better represented in the fossil record.
Abundance bias
what does Precambrian mean?
collective name for first three eons
what does the precambrian include?
Hadeon, Achaean, Proteozoic.
4.6 bya –> 542 mya
-most life was unicellular throughout most of this time
- low O2 levels for first 2 billion years after life evolves.
What does the Phanerozoic eon include?
3 eras: Paleozoic, Mesozoic, Cenozoic
542 mya –> present
What is a Niche?
The niche of an organism is the functional role that it plays within an ecosystem.
Define Adaptive radiations
when a single lineage rapidly diversifies into many desendant lineages with a wide diversity of forms and ecological niches
___________ – favourable new environmental conditions = Ecological opportunity *islands
Extrinsic
e.g. adaptive radiation of 150 species of anolis lizards in the carribbean islands
_____ – evolution of innovative morphological, physiological, or behavioural traits
Intrinsic
ex.
Flowers – innovative reproduction structure that led to diversification of angiosperms into 250,000 species.
Feathers/wings – innovative morphology (feathers) that gave some dinosaurs the ability to fly. Today there is ~10,000 species of birds.
what does Daushantuo mean?
microscopic early animals