Exam 3 Flashcards
(36 cards)
Define Microevolution
Change in the genetic composition of a population across generations
Define Macroevolition
Large evolutionary changes including the formation of new species and taxa
What is the gradualism model of evolution?
Evolution occurs by the gradual accumulation of small changes
What is the punctuated equilibrium model of evolution?
Evolution consists of long periods of stasis with little to no evolution interrupted by short periods of rapid change
Stasis is due to __________
Strong stabilizing selection
What is IDA? Where would we expect to find it on a phylogenetic tree?
Initial Darwinian ancestor, most likely seen furthest back
What is LUCA? Where would we expect to see it on a phylogenetic tree?
Most recent common ancestor of all extant organisms, seen at the base of a group of living creatures
What three components are needed for life?
Molecules to catalyze reactions
Cell membrane
Ability to replicate
What are the 4 origins of life questions?
Where do biomolecular compounds come from?
What reactions fueled early life?
How do building blocks self assemble into polymers?
How were large biomolecules protected from harsh environment?
Define Pasteur’s cell theory
Living things came from other living things
What was the Miller-Urey experiment? Why was it important?
Recreated earths original atmosphere and conditions and within days organic molecules including amino acids appeared
Define the RNA world hypothesis
Short RNA molecules could have formed spontaneously that were capable of catalyzing their own replication
Define the garbage bag world hypothesis
Molecules come together inside of a “bag” and reproduce with RNA coming along as a parasite and DNA evolving in a coevolutionary arms race with RNA parasites
Describe the universal gene exchange pool. What controversies are there?
LUCA between bacteria, archaea, and eukaryotes was not a single species but a pool of readily exchangeable and independent genes in which the three cellular forms emerged. Controversy: no evolution via natural selection until Darwinian threshold is reached
Define the ring of life hypothesis. What controversies are there?
Eukaryotes arose when a bacterium fused with an archaean. Controversy: most likely they arose independently of eachother, no explanation for the hundreds of eukaryotic only proteins, arches and bacteria lack cytoskeletons that enable phagocytosis
Define the Chronocyte hypothesis. What controversies are there?
Evolved a cytoskeleton and the ability to do phagocytosis which then ate an Archean which became the nucleus. Controversy: chromocyte with a skeleton but no nucleus and mitochondria has not yet been found
What features do homosapians have that primates do not? (There are 9)
Less robust face and skeleton
Less body hair
Changes in pelvis, hands, feet
Social behavior
Language
Delayed maturity to reproductive age
Menopause
Large brains
Longevity
Define the out of Africa hypothesis
A second migration out of Africa happened about 100,000 yrs ago in which modern humans of Africa colonized the world replacing the archaic human populations
What evidence supports the out of Africa theory?
Tool making technology arose in Africa
Earliest human fossils are in Africa
Genetic data and phylogenetics
mtDNA gene trees
How did genetic variation arise in humans?
Mutation
Hybridization with Neanderthals
Natural selection
Inbreeding
Genetic drift
What were the fitness costs for humans?
Entering environments they were not yet adapted to
How have humans evolved to have bigger brains?
Improved diet quality and an increase in net energy input to the brain
Proximate causes are ______ driven
Symptom
What are ultimate causes
Trade offs
Evolved host defense
Gene-environment mismatch
