Anth 196 Exam 2

Evolutionary Synthesis

Early modern synthesis. Reconciled transmission genetics and key evolutionary principles. Emphasis on how evolutionary forces shape populations.

Late Modern Synthesis

Brought other natural sciences such as ecology, taxonomy, biodiversity, and paleontology into the field.

What are the two kinds of evolution

Macroevolution and Microevolution

Microevolution

Occuring below the species level. Usually operates over much shorter time scales and can sometimes be synonymous with "population genetics"

Macroevolution

Evolutionary change that results in the production of new species. Operates under much larger time scales.

Biological Species Concept

Focuses on reproductive isolation among groups, specifically factors that reproductively isolate different groups.

Allopatry

Species living in different geographic area

Sympatry

Species living in the same geographic area

Allopatric Speciation

New species form due to initial geographic isolation or seperation

Which two evolutionary forces can create genetic divergence between groups that have become isolated from one another, helping give rise to new primate species?

Natural selection and Genetic drift

Founder Effect Speciation

An isolating event in which small populations become separated from their "parent" population. Over time, this may cause reproductive isolation to evolve.

Geophysical features effect on speciation

They can create isolation among populations, as with plate tectonics, meteor impacts, and climate change, driving cycles of speciation and extinction.

Other bio-geo-physical factors causing extinction

Global climate change, predation, competition, sea level change, volcanic eruptions, and asteroid impacts, large-scale extinctions can trigger adaptive radiations

Adaptive radiation

The rapid expansion and diversification of species into new ecological niches

Under which circumstances may an adaptive radiation occur?

Extinction of competitors, colonization of areas with no competitors, and adaptive breakthroughs

Intraspecific Variation

Variation among members within a species due to sex, age, or individual variation

Interspecific Variation

Variation between two or more species due to the fact that each is characterized by species-specific genes

Paleospecies

A member of a past lineage

John Ray

Coined terms "species" and "genus." Recognized that groups of species were sometime similar and could be grouped into genera.

Carl Linnaeus

Developed hierarchal classification scheme of nested groups, formalized bionomial nomenclature

Taxonomy

Theory and practice of classifying organisms to name and group earths species into a coherent framework

Homologous traits

Those that are present in two or more species that are also present in the common ancestor of those species

Analogies

Superficial similarities of features that are based on a common function, not common ancestry. Ex. lack of wing-like structure in bats and flies

Recognizing homologies

Same basic structure, same relationship to other features, and same development

cladogram vs. evolutionary tree

A cladogram shows relationships based on common ancestry with only relative time (recency of common ancestry); an evolutionary tree also shows lines of descent over actual time

Cladogram

Diagrams of relationships based on common ancestry. They are the first step in building an evolutionary tree. They have relative time components; it reflects relative recency of common ancestor

Evolutionary Tree

Diagrams that show evolutionary relationships and lines of descent between different species or organisms from a shared ancestor

Lithospheric plates

Positions ocean floors and continents. Floats on a hot and dynamic asthenosphere. Can cause geological change by collision and subduction of plates that cause mountains to form

Holocene

The geological era since the end of the Great Ice Age about 11,000 years ago.

Miocene

23-5 mya

What were the two major landmasses 125 million years ago?

Laurasia and Gondwana

Which reproductive features distinguish mammals from reptiles?

Mammary glands (milk), suckling/nursing, live birth (viviparity) in most species, and extended parental care with a long period of offspring dependency

Metabolism and Heat regulation differences

Endothermy, body hair, sweat glands, and a diaphragm

Endothermy

Ability to generate constant body temperature from internal metabolism.

Cranial Anatomy Differences

Small bones that transmit sound vibrations are homologous with reptile jaw bones. Brain size much larger relative to body size

Dental Anatomy Differences

Reptiles have different kinds of teeth, mammals have four; incisors, canines, premolars, molars.

What is the difference between heterodonty and diphyodonty in mammals?

Heterodonty: having different types of teeth; Diphyodonty: having two sets of teeth (milk teeth and permanent teeth)

Hereterodonty

Having diiferent kinds of teeth

Diphyodonty

Two sets of teeth, milk teeth and permenant teeth

Cerebellum

The part of the brain that control movement and coordination.

Neocortex

“Higher level” thinking. Recieves sensory input and produces approriate behavioral responses.

Dental Formula

the number of upper incisors, canines, premolars, and molars in the upper tooth row (one quadrant of the mouth) over the number of lower incisors, canines, premolars, molars, in the lower tooth row (one quadrant of the mouth) Humans= 2.1.2.3

Characteristics that define primates: Post Cranial

Five fingers and toes, prehensile hands, nails instead of claws, tactile pads on fingers and toes, and an opposable big toe

Characteristics that define primates: cranial

Reduced olfaction, emphasis on vision (postorbital bar, convergent eyes/stereoscopic vision, well-developed visual processing), and a large brain relative to body size

Compared with many other mammals, which life history pattern is typical of primates?

Long lives, late reproduction, single offspring, long interbirth intervals, and high parental investment in each offspring

Characteristics that define primates: Ecology

Tropical distribution, omnivorous diet, and (in some species) diurnal activity and group living

Arboreal Hypothesis

Primate traits arose in response to life in a 3D environment. Living in trees requires good vision, grasping capabilities, and a somewhat advanced brain.

Visual Predation hypothesis

Aboreality alone cannot account for primate traits because squirrels and other mammals get along fine without these traits. Convergence of traits with other visually oriented predators like owls and cats

Which description fits lemurs and lorises?

Africa, Asia, Madagascar; tooth comb, grooming claw, smaller brain, rhinarium, tapetum lucidum; live in groups or dispersed

Which description fits tarsiers?

Southeast Asia; grooming claw, no tapetum lucidum, no tooth comb; nocturnal; dispersed or solitary

Which description fits platyrrhines (New World monkeys)?

South America, Central America, southern Mexico; arboreal, some with a prehensile tail; live in gregarious groups or pairs

Which description fits cercopithecoids (Old World monkeys)?

Africa and Asia; terrestrial and arboreal; split into cercopithecines and colobines; live in pairs or gregarious groups

Which description fits hominoids (apes and humans)?

Generally large body size, no tail, complex social behavior, large brain, long infant dependency, 2.1.2.3 dental formula

Describe lemurs and lorises: where do they live, what are their key traits, and how do they live socially?

Africa, Asia, Madagascar; tooth comb, grooming claw, smaller brain, rhinarium, tapetum lucidum; live in groups or dispersed

Describe tarsiers: where do they live, what are their key traits, and how do they live socially?

Southeast Asia; grooming claw, no tapetum lucidum, no tooth comb; nocturnal; dispersed or solitary

Describe platyrrhines (New World monkeys): where do they live, what are their key traits, and how do they live socially?

South America, Central America, southern Mexico; arboreal, some with a prehensile tail; live in gregarious groups or pairs

Describe cercopithecoids (Old World monkeys): where do they live, what are their key traits, and how do they live socially?

Africa and Asia; terrestrial and arboreal; split into cercopithecines and colobines; live in pairs or gregarious groups

Describe hominoids (apes and humans): what are their key traits?

Generally large body size, no tail, complex social behavior, large brain, long infant dependency, 2.1.2.3 dental formula.

Locomotor Behavior

Moving around in their habitat. solves problems of finding food, avoiding predators, and finding mates.

Postural behavior

Remaining stationary in a given location. solves problems relating to harvesting food and resting.

Which two food types do primates most seek, and what does each provide?

Protein (growth and basic body functions; from insects, leaves) and carbohydrates (a ready source of energy as sugars, starches, and fibers; from fruit, flowers)

Basal Metabolic rate

Rate of energy expenditure to maintain life when at rest

Protein (Insect)

Lots of protein, easy to digest, abundant, but difficult to find. High-quality but inconsistent

Protein (Leaves)

High in protein, hard to digest, abundant, and easy to find. Low-quality source but consistent

Insect Eaters

Insectivores. Have simple digestive systems. Pointy cusps.

Leaf Eaters

Folivores. Specialized stomachs to break down cellulose. Relatively flat teeth

Nocturnal

Active at night (many prosimians, owl monkey)

Diurnal

Active during the day (monkeys, apes, humans)

Cathemeral

Active during day and night (lemurs)

Home range

A fixed geographic area where a primate individuals or groups move about

Group living benefits

Protection from predators. Enhanced ability to find and defend food resources

Philopatric

Remaining in one's natal group or home range as an adult. usually female, males tend to disperse

Contest compeition

direct competition. occurs when food patches are clumped, small, and defendable.

Dominance and Contest competition

Dominance is the predictable relationship between individuals established via fighting or aggressive displays of strength. Dominance relationships are the outcome of a dispute over a fitness-enhancing contested resource

Priority access

Occurs due to contest competition, 1st rank gets first access, 2nd rank gets second access and so on

Scramble Competition

Indirect competition. Occurs when food patches are low value, large, and highly abundant

Female investment in reproductive success

More investment than males. Large, limted production of egg cells, long gestation periods, and long periods of lactation.

Male investment in reproductive success

Produces small, numerous sperm cells. Do not gestate or nurse young.

Female reproductive strategy

Because of females higher investment in offspring produciton, selection will favor females who choose thier mates carefully.

Male reproductive strategy

Increase reproductive success by increasing their number of mating partners. They are less choosey. Number of males in a group largely depends of distribution of females.

Monogomy vs. polygny

Monogamy: Males pair up with a single female. Polygyny: one male monopolizes the entire group

Solitary dispersed groups

Male ranges overlap with several solitary female ranges

multi male/female groups

Many males join large female group

Precopulatory

Intrasexual competitive pattern focused on fighting

Postcopulatory

Intrasexual competitive pattern focused on sperm competition

Reproductive altruism

help your relative reproduce even if it means that you may not reproduce yourself

William Hamilton

Proposed selection would favor altruistic behavior when helping a relative provides greater genetic benefit than the cost to the helper.

Relatedness and Kin-selection

Relatedness is the proportion of genes shared between kin

Hamilton's rule

r*b>c

r: relatedness value

c: cost of the altruistic act to the actor

b: benefit of the altruistic act to the recipient

Alarm calls

unique vocalizations produced when a predator is nearby. evolved under kin selection

Affiliative Relationship

Positive partnerships and interactions among kin

Affiliative behavior (Grooming)

Major functions: hygenic and social bonding