ANTHRO 001 MIDTERM 1

Evolution

change in frequency of a trait through time (trait = genotype of phenotype)w

Microevolution

change in allele frequencies within a population over short time scales

Macroevolution

large-scale evolutionary changes above the species level resulting form long-term microevolution

What are the three types of evolution paces?

stasis: constant linear

gradual change: increasing linear line

Punctuated change: straight line —> rapid increase —> straight line

What are the mechanisms of evolution?

Mutation

Gene Flow

Genetic Drift

Natural Selection

Which ones are neutral evolution?

Mutation

Gene Flow

Genetic Drift

Darwin’s Postulates

The following 3 postulates make evolution by means of natural selection inevitable:

• struggle for existence

• variation in features related to survival and reproduction

• variation is passed from generation to generation

What are the three types of selection?

Disruptive: climate changes disrupt selection pressures on populations

Stabilizing Selection: maintain status quo as long as the environment is constant

Directional: one trait favored to another trait

Artifical: Domesticate and selective breeding

Sexual Selection

Variance in mating success of members of the same sex and selects for traits that increase the relative fitness of an individual by allowing them to secure greater mating success.

Intrasexual Selection

Male competition where dominant males gain access to females

Intersexual Selection

Femalce choice where female select most attractive male

Monogamy

Individuals mate exclusively with each other

Polygamy

individuals mate with more than one partner

Polygny

males mate with more than one female

Polyandry

females mate with more than one male

Promiscuity

individuals mate indiscriminately with multiple partners

What are the female preferences for male behavior?

grooming

access to resources

protection

Theory of Evolution

1. Overproduction: species tend to reproduce more than one can survive to maturity

2. Variation: individuals of a population have many different characteristics

3. Selection: individuals survive longer and reproduce more than others

4. Adaptation: those that survive pass on their traits to their offspring (the favored traits will be more common in the population)

Global optimum

The “best” solution for natural selection to reach/achieve in a population.

Local optimum

The “good” solution for natural selection that sometimes, (normally) reaches in a population.

What are ways humans have affected evolution of our and others species?

Habitat Destruction

Overexploitation of resources

Invasive Species

Pollution & Environmental Changes

Artificial Selection

Cultural & Tech Buffering

DNA

Deoxyribonucleic acid

Unit of inheritance that contains the ‘recipe’ for creating and differentiating cells into a whole organism

4 nucleotide bases

Adenine

Guanine

Cytosine

Thymine

How many chromosomes do Humans typically have?

22 + the sex chromosomes = 23

Mitochondiral DNA

Very short chromosome that is maternally inherited and has multiple copies

Diploid

2 copies and recieve 1 copy of each chromosome from each parent

Meiosis

2 ways that create new genetic variation

• 50% chance that parent will pass on either chromosome of given homologous pair

• genetic recombination ensures offspring will have different genetic makeup

Gregor Mendel

Discovered laws of inheritance from breeding garden pea plants

Law of Segregation

Characteristics of organisms are determined jointly by two articles, one inherited from each parent

Law of Independent Assortment

“particles” for different traits are independently inherited. Genes do not influence each other with regards to the sorting of alleles into gametes

Law of Dominance & Uniformity

Some “particles” are dominant over other particles

Hardy Weinberg Equation

Determines if evolutionary chance is taking place or in equilibrium

p² + pq + q² = 1

Hardy Weinberg Equilibrium

Population is infinitely large

No mutation

No genetic drift

No gene flow

Natural selection is not operating

Mating is random

All members produce same number of offspring

Heritability

How much of a trait is genetic and how much is something else (environment)

H = (variation accounted for by genotype)/(total variation)

Mutation

A spontaneous change in the chemical structure of DNA

What are the three types of Mutations

Harmful: negatively affects

Neutral: no affect

Beneficial: positive affect

Gene Flow

Introduction of genetic material from one population/species to another through reproduction of migrating individuals

Genetic Drift

Random change in a gene frequencies b/c of smapling variaiton that occurs in any finite population

Bottleneck event

And even that decreases and numerically harms an original population that alters and decreases gene frequencies

Founder’s Effect

Gene flow through chance isolation

Serial Founder Effect

Explains the genetic drift of Archaic Homo sapiens in the African continent

Migration out of Africa into other continents continued as serial founder effects

Do most human variation exist within or between groups?

Within

Mutation

increases variation WITHIN a group and BETWEEN groups

Genetic Drift

decreases variation WITHIN a group, but increases variation BETWEEN groups

Genetic Flow

(usually) increases variaiton WITHIN a group, but decreases variation BETWEEN groups

Modern Evolutionary Synthesis

Evolutino is genetic and measurable

Multiple forces shape evolution

Ronald Fisher

Menedlian inheritance explains continuous traits

JBS Haldance

Mathematical equations for NS and mutations

Sewall Wright

Genetic Drifts and Fitness Landscaoe

Theodosius Dobzhansky

created definition of evolution (showed the evolution works in nature, not just models or theory)

Extended Evolutionary Synthesis

Added New drivers to evolutionary changes such as development bias, niche construction, and non-genetic ways of inheritance

Current Evolutionary Theory

Evolution is shaped by genes, development, plasticity, and environment

Organisms modify their own selection pressures

Non-genetic inheritance

Works to explain rapid adaptation and evolutionary innovation

Main characteristics of a Primate

Grasping Hands and feet

Nails instead of claws

Limb driven locomotion

Reduced sense of smell, enhanced vision

Forward-facing eyes

Large brain to body size

Long gestation

Small litters

Long juvenile period to learn

Long lifespan

Increased dependence on learning and behavioral flexibility

What are the major proximate theats to primates?

Habitat loss

Hunting & Capture

Disease

Life History Theory

Trade-offs and energy allocation
difference between fast life historu (r-selected) & slow life history (k-selected)

R selection

short lived

small body size

fast maturation

low infant investment

early reproduciton

K selection

Long lived

Large body size

reproduce at a larger age

slow maturation

high infant investment

Menopause

natural end of menstruation, usually defining the end of period cycles

‘Grandmother’ Theory

Defines how menopause is evolved by older women to increase inclusive fitness by helping raise children (increase grandmother survival by tring to have more children later in life), enhancing genetic success and explains why human females live long post-reproduction, unlike most other mammals.

Primate Socio-ecoloy

Study of how primate social systems among primate societies are influenced by the environment

Primate Dentition

(ICPM) for upper and lower Dental Formula)
I —> Incisors

C —> Canines

P —> Premolars

M —> Molars

Jarman/Bell principle

The consequences of the negative allometric relationship between body mass and nutritional requirements,

Large-bodied species need LESS energy per mass unit than small-bodied species

Reasons for Living in groups

• lowers predation risk

• improves predator detection

• allows collective defense (mobbing behavior)

Pair-Bonding Species

mate guarding, increased parental investment,

Cooperative Breeding

Males & other individuals in group help raise the young

Infanticide

A male reproductive startegy

Predictions:

• change in male residence or status and only kill insnats taht result in resumption of female crying

Data:

• takeover by new male follows 85% of deaths

• unweaned infants primarily targeted

Weaning

the process of energy becoming more available for the mother once nursing and dependance on mother from offspring gradually decreases

Sociality

Females baboons form strong social bonds that result in more reproductive success and live longer

Altruism

A behavior that helps another organism at a cost to the actor’s own reproductive fitness (sacrifices its own fitness for the sake of their group’s fitness)

Kin Selection

Not all members of a group are equally related and related individuals often cluster

W.D. Hamilton’s rule

rb > c

• r = coefficient of relatedness between actor and recipients

• b = sum of benefits to individuals affected by behavior

• c = fitness cost to individual performing behavior

Kin selection

Natural selection favors altruistic behaviors that increase the reproductive success of close relatives, even at a cost to the individual’s own survival or reproduction

Inclusive Fitness

A better measure of fitness

NS favors strategies that increase inclusive fitness

(Direct fitness + Indirect Fitness) * Increased probability they share a given allele [r]