BIO 171 EXAM 3|97 QUESTIONS AND
ANSWERS
two major tools biologists use to study life - -fossil record and phylogenies
-limitations and biases of fossil record - --habitat (likelihood of fossilization
depends on habitat)
-temporal (old vs new)
-taxonomic (characteristics of organisms)
-abundance
-Hadean Eon - -4.5-4 BYA
-no oxygen
-volcanic activity
-no life
-meteors crashing into earth
-first evidence of liquid water
-Archean Eon - -4-2.5 BYA
-a little oxygen
-still volcanic activity
-first sign of life (prokaryotes-3.8 BYA)
-oceans
-first bacteria (3.5 BYA)
-origin of photosynthesis (3.5 BYA)
-Proterozoic Eon - -2.5 BYA- 542 MYA
-first eukaryotes (1.8 BYA)
-animals (simple sponges-600 MYA)
-cyanobacteria (3.5 BYA)
-more oxygen in atmosphere and surface of oceans (2.4 BYA)
-oxygen catastrophe
-Cambrian Explosion - --animal phyla popping up
-marine life
-adaptive radiation: rapid speciation
-Phanerozoic Eon, 540 MYA
, -3 Major Lineages of Mammals - -1. Marsupials
2. Placentals
3. Monotremes
-Which traits characterize primates? - --nails instead of claws
-eyes on the front of the face
-3D vision
-5 grasping fingers
-What two pieces of DNA indicate that Homo Sapiens evolved in Africa about
200,000 years ago? - --mitochondrial DNA
-y chromosome data
-When did Homo Sapiens evolve in Africa? - -about 200,000 years ago
-What are the abiotic factors (density independent) that influence population
size? - --temperature
-pH
-salinity
-disturbance
-pollution
-precipitation
-What are the biotic factors that influence a population size? - --predation
-competition
-mutualism (cannot regulate a population)
-disease
-parasitism
-regulation - --only biotic factors can regulate a population (not mutualism
though)
-requires negative feedback
-wants to keep things in equilibrium
-density- dependent factors
-What is rmax? - --maximum rate of increase of the population
-when births are as high as possible and deaths are as low as possible
-What determines K? - -competition within a species for resources
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