BioA 201 Midterm

Study of the evolution of and biological variationin humans and their closest relatives, includingprimates and fossil ancestors.

• features oforganisms that:
• help them surviveand reproduce
• are createdthrough evolutionby natural selection

• look like a more harmful model
• red touches black youre okay jack, red touches yellow youre a dead fellow

• For adaptation to occur,there must be:
• 1. Struggle for Existence
• 2. Variation in Fitness
• 3. Inheritance of Variation

• 1. HMS Beagle trip
• 2. Thomas Malthus- That population grows exponentially even though resources are finite
• 3.Charles Lyell- the earth is REALLY old
• 4. John Baptiste Lamarck- giraffes with growing necks, WRONG
• 5. Carolus Linnaeus- systema natural, the early tree of animals
• 6. Eramus Darwin- his grandfather who believed in evolution
• 7. Alfred Russell Wallace- other scientist who thought up natural selection and made him want to publish

• directional- changes average value, takes away one extreme
• stabilizing- normalizes to equillibrium, takes away both extremes
• disruptive- takes away the average trait, creates two high points of with side of average

• Complex adaptationsarise through theaccumulation of small changes
• Improbable with justrandom variation
• Probable whenchanges are additive
• Intermediate stepsmust each be favoredby natural selection

• Convergence isevidence that complex adaptations don’t arise bychance.
• Organisms share very similar adaptations, but not because of common lineage.

Methinks it is like a weasel, simulator

inherited traits were determined, randomly, from a range bounded by the homologous traits found in the parents

1859 book was published

pea plants for genetics

• continuous- bell-curve, you can have very little of extremes, but intermediate values in between each
• dis or non continuous- only a specific thing

states that allele pairs separate or segregate during gamete formation, and randomly unite at fertilization.

when parent has variation that is an equal chance of both to be passed

• Chromosomes contain the genes that allow traits to be transmitted
• Chromosomesreplicate themselvesin two ways… mitosis and meiosis

normal everyday cell division

replicate into haploid cells

half of what is needed for fertilization

both sets together, one haploid from mom and one from dad

Portion of chromosome that has arecognizable effect on phenotype.

Variety of genes with the sameeffect on an organism.

Particular combination of genesand alleles an individual carries.

Observable characteristics of anorganism.

Individual with two copies of thesame allele for the same gene.

Individual with copies of twodifferent alleles for the same gene.

Only 1 copy of allele to expressphenotype.

2 copies of allele to expressphenotype.

that there are two dominant genes AB blood-type

Individuals genotypes cause phenotypes

• genes in nucleus of cells
• RNA carries DNA’s message to its cytoplasm (outer area)
• Structure of RNA, with paired bases, matches DNA
• DNA, with RNA’s assistance,initiates and guides the construction of hundreds of proteins necessary for bodily growth, maintenance, and repair

pairs with thymine, u in mrna

pairs with adenine

pairs with cytosine

pairs on guanine

• mRNA takes DNA’smessage fromnucleus to cytoplasm
•  tRNA helps to stringtogether amino acidsin protein
•  Similar structure toDNA but
•  Thymine (T) substitutedfor uracil (U)

• Strings of amino acidsmake proteins
•  Body is made of proteins
•  Collagen
•  Keratin.

• Mutations
•  Change the message of DNA
•  Can change proteins Can change phenotypes
•  Some mutations are deleterious
•  Some mutations create new variability that natural selection can work with
•  Other mutations are neutral
• Mistakes in copying DNA
•  Important for generatingand maintaining variation

gene sequences that don’t code for anything

like the ones that code for proteins

that determine condition under which genes express themselves

• Changes in populationgene frequencies byrandom chance
•  Chances of occuringincreased by smallpopulation sizes
•  Coin-flip experimentdemonstrates

• Genetic drift canoccur when a smallpopulation breaks offfrom a larger one
•  Founder’s Effect
•  High frequency of Oblood type amongnative populations ofN. and S. America isprobably from geneticdrift

• Exchange of genetic material betweenpopulations of the same species
• – Alleles spread through gene flow evenwhen selection not operating on the alleles
• – Species
• – group of related organismswhose members can interbreed to produceoffspring that live and reproduce
• – Gene flow tends to prevent speciation
• –formation of new species

• Freq aa= q^2
• Freq AA= p^2
• Freq Aa= 2pq

• genes code for a range oftraits or behaviors
•  Behavior – more variableand changing
•  Morphology – little or nochange after developmentfor many traits, others arephenotypically plastic

• Microevolution –changes in population gene frequencies
• Macroevolution- processes that lead todevelopment of newspecies and highertaxonomic levels

• Species are populationsof organisms that caninterbreed and arereproductively isolatedfrom other organisms
• • Gene flow inhibits theevolution of new species

• Allopatric- different
• Parapatric– Strong selection for twodifferent phenotypes inneighboring habitats– Hybrid zones occur atboundaries of habitats– But hybrids are less viableso there is selectionagainst it
• Sympatric– Strong selection evenwithout geographical seperation

no variation

• When a single type oforganism diversifiesthrough macroevolution tofill a variety of niches
• Occurs when there aremany empty niches
• Rate of speciation relatedto number of open niches

similaritiesthat organisms share because of common ancestry

• Ancestral characteristicsare distinguished by:
• – They appear earlier inorganismal development
• – They appear earlier in thefossil record
• – They are seen in outgroups

similar traits that arise if species experience similar selective forces and adapt to them in similar ways

• Long-term study of wildchimpanzees
• ? Started in 1960 (age 26)

• Hands and feet:? Ancestral number offingers and toes? Hands are “prehensile”? Feet have “opposable” bigtoes? Nails instead of claws
• ? Increased importanceof sight; decreasedimportance of smell?
• Vision:? Stereoscopic? Color?
• Brain:? Portion for sight(larger)? Portion for smell(smaller) -Brain to body size ratio exceedsother animals, even othermammals
• ? Teeth:? Molars unspecialized? Max. per quadrant:? 2 incisors? 1 canine? 3 premolars? 3 molars
• Parental investment much higher
• Typically live in groups

• ? Three infraorders:? Tarsiiformes? Lemuriformes? Lorisiformes
• ? Found in Asia & Africa? Lemurs & galagos (Africa)? Lorises & tarsiers (Asia)
• ? Mostly nocturnal –active at night
• ? Vertical Clinging andLeaping (VCL)

? Monkeys, apes, & humans? Anthropoid suborder has twoinfraorders:? Platyrrhines – flat nosed, NewWorld monkeys? Catarrhines – sharp nosed, OldWorld monkeys and hominoids? Monkey vs Hominoid:Catarrhines? Monkeys have tails? Hominoids (apes & humans) do not

• ? Live in forests ofCentral and SouthAmerica
• ? Two families:? Cebidae? Capuchins? Howler monkeys? Spider monkeys
• ? Callitrichidae? Marmosets? Tamarins
• ? Lack full colorvision

• ? Dental formulameasures number ofteeth in one quadrant ofmouth? = # incisors: # canines: #premolars: # molars
• ? 2:1:3:3? Prosimians? New World Monkeys
• ? 2:1:2:3? Old World Monkeys? Apes? Humans

• ? Molars of Old-Worldmonkeys are bilophodont
• ? Cusps form twoparallel ridges
• ? Molars of hominoidshave a patterncalled “Y-5”
• ? Five distinct cuspswith a Y shapethrough them

active anytime (intermittant)

active during dusk

maintainingexclusive access to fixedareas

one male, one female

one female, multimale

one male, multi female

Infanticide

selfish genes

number of gene copiesto next generation

rB > C

much like altruism but within family

• sister/brother/mother/father .5
• grandma/grandpa/half sibling .25
• aunt/uncle/neice/nephew .25
• cousin .125

Traits that increase one sex’sability to compete for matesof the opposite sex

• All organisms facetradeoffs
•  Energy constraints and theprinciple of allocation

All organisms, includingprimates, deterioratephysically with age

• Monkeys, apes, & humans
• ? Anthropoid suborder has twoinfraorders:
• ? Platyrrhines – flat nosed, NewWorld monkeys
• ? Catarrhines – sharp nosed, OldWorld monkeys and hominoids
• ? Monkey vs Hominoids
• ? Monkeys have tails
• ? Hominoids (apes & humans) do not

• VCL- verticle clinging and leaping
• quadraped- all fours
• knuckle-walkers

a form of genetic drift that occurs when a small population of colonizes a new habitat and subsequently increases it number. random gentic changes due to small number of initial population are amplified by subsequent population growth

a trait that was not present in ancestral traits

flat nosed, NewWorld monkeys

sharp nosed, OldWorld monkeys and hominoids

• Capuchin
• s? Howler monkeys
• ? Spider monkeys

? Tamarins

Baboons? Macaques? Langurs

• Lesser Apes – gibbons,and siamangs
• ? Great Apes – orangutans,chimps, gorillas
• ? Humans