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Evolution and Psych Exam 2

Terms in this set (60)

How long ago were continental shifts taking place?
225 million years ago
How long ago did water shadows and forrest fragmentation occur?
15 - 2 million years ago
Around ___ million years ago, the climate began to cool, resulting in...
50; less rain, meaning a breaking up of tropical rain forests and an expanding of grasslands
__ - __ million years ago, the climate continued cooling, causing...
15-3; temperate forests and grasslands moved toward the equator and tropical forests continued to decrease in size
The most important result of climatic cooling what was?
Changes in selective pressures
What did these selective pressures first influence?
Our shift from arboriality to terrestriality
Milkankovitch cycle
1 of 3 types of variations in Earth's rotation and orbit around the sun that result in slight changes in the relative amount of solar radiation reaching Earth's surface at different latitudes. Cycles proceed, change the way solar radiation is distributed over Earth's surface and contributes to changes in atmospheric heating and circulation that have triggered the ice ages and other climate changes
How do the Milankovitch cycles related to microshifts in climate?
The cycles represent a pattern in Earth's tilt that causes small shifts in the climate over long periods of time (temperature patterns)
Does temperature have an effect on phenotype?
Yes
What is characteristic at low latitudes and warm temperatures? Why?
Smaller, narrower body types are more adaptive because ability to lose body heat is important
What is Allen's rule?
As elongation of body increases, ratio of surface to mass increases
What is characteristic at high latitudes and cold temperatures? Why?
Larger, broader bodies because heat retention is important
What is Bergman's rule?
As body mass increases, ratio of surface area to mass decreases
What types of mechanisms/behaviors does temperature effect?
Termoregulation, foraging, habitat selection, movement, parental strategies
What is a possible pathway for latitudinal increase affecting behavior?
Latitude increases - foraging strategies must adjust to account for food availability and necessary caloric intake to stay warm, etc. - habitat influenced - mating strategies for desirable qualities - parenting strategies
How many million years ago did the first apes appear?
35 mya
How many years ago was the closest ancestor to existing apes?
22 mya
What are some cautions in interpreting hominin milestones?
Sparce fossil record, few parts of a specimen are usually found, interpretation of a fossil is often difficult, minimal examination of variation, use of existing structure/function relationships
Sparce fossil record
Disagreement often occurs about specimens because there are not enough (numerically) to prove anything consistently
Few parts of a specimen are usually found
Hardly ever who sections or whole bodies
Usually part of a skull, jawbone, etc.
Hardly ever any kinds of tissue
Interpretation of a fossil often difficult
Dead bodies will probably be used for some other purpose by some other creature, remains are rarely intact, cause of death may be uncertain due to postmortem activities, remains are hardly ever found where they died
Minimal examination of variation
Hard to determine
Use of existing structure/function relationships
We interpret the function of remains in relation to contemporary structure/function relationships
It's all postulation, there's no way to know for sure
Explain old via new
During great periods of climate change, there were lower/higher rates of speciation events with ____ stasis
Higher; punctuated
Our lineage begins when the climate shifted from warm and seasonal to...
Cool and dry
Are we a relatively young or relatively old species?
Young, ~200,000 years in a six million year lineage
What are two profound effects of colliding plates/continents?
1. when 2 plates come together, previously isolated/unfamiliar species will be forced to interact (new food web, new selective pressures)
2. Elevation and climate will change as well, leading to novel climatic and biotic selective pressures also
We live in a static/dynamic planet
Dynamic
What are some ways to analyze teeth to evaluate diet?
Thickness of enamel, chemical composition, scarring from silica in plants and pitting from carnivorous diets
How does enamel correlate to diet?
Thin enamel indicates a primarily frugivore diet (softer skin) while thick enamel is typically found among omnivores/carnivores (more terrestrial food - thicker)
What were Ardipithecus thought to eat?
Thought to be frugivores heading toward omnivory
Australopithecus was thought to be primarily _____, which is evidenced by little evidence of...
Vegetarian; little evidence of tools and prey bones
What is thought to be the primary function of canines in primates? What does this tell us about assumption of function?
Social displays (mating, aggression)
We must be careful not to assume a primary functions, we must take into account other advantages
Did scavenging likely proceed or come after hunting?
Proceed
How long ago were the first tools seen? Which common ancestor is this attributed to?
2.5 mya, homo habilis
What were tools like? What did this indicate?
Unifaced, simple
Indicated a shift in diet toward meat
When did the first bifaced tools appear? Which common ancestor is this attributed to?
1.6 mya, homo erectus
How long ago was fire postulated to have appeared?
1.5-1 mya (also homo erectus)
What implications did emergence of bifaced tools have?
Bifaced tools lead to hunting game (rather than scavenging) and, eventually, more efficient and effective hunting, changing strategies
What implications did fire have?
Softens connective tissues in animal tissue, denatures proteins, gelatinizes plant material - more efficient nutrient absorption --> able to support bigger brain?
Homo erectus
Moved out of Africa, began to develop a larger brain, bifaced tools emerged that enabled actually killing of animals (hunting) -> smaller ribcage (more efficient digestion)
500,000 years ago, with homo heidelbergensis, came what kind of prey? What were the implications of this?
Spears, hunting of larger prey --> social function of hunting (coordinated efforts)
Homo sapiens emerged how many years ago?
250,000 years ago
What were the eating habits of homo sapiens?
Focus on large game
How long ago was the advent of the bow? What did this mean?
70,000, this meant that hunting efforts did not HAVE to be coordinated
What occurred 40,000-30,000 years ago?
Ice age began, an increase in specialized tools took place
Around 30,000 advent of nets leads to fishing as a source of food
When did the ice age end?
10,000
What was implicated by the end of the ice age?
A reduction in large prey and an increase in small prey
Agriculture began to occur as a source of food, domestication of animals to ensure consistency
What does the EEA assume?
That there isn't a lot of selection operating
What is the problem with this?
The emergence of agriculture, raising of livestock
What is an example of cultural adaptations/changes causing biological adaptations?
Use of milk produces increased lactose tolerance and selection for lactose metabolizing gene (lactase)
What is the selective advantage of milk tolerance?
Source of nutrition, protein and vitamin D, especially in areas of low sunlight
What is the problem with evaluating extant hunter/gatherer societies?
Technology is pervasive, so it is difficult to assess from a historical perspective
What biogeographic variation is visible at higher latitudes v. lower latitudes?
Lower latitudes - more plants and gathering
Higher latitudes - larger prey/hunting
What is the average group size according to Marlowe?
26 individuals
What are some constraints on group size?
Availability of primary biomass, processing of social information (too much stimuli)
Can sexual differences in the division of labor be expected? If so, how is this affected by latitude?
Yes, at lower lats, there is more gathering and therefore greater division and at higher lats, there is limited gathering and therefore lesser division
What is group egalitarianism in this sense?
Resources are shared among individuals
How does this relate to kin selection?
Want to allow kin an equal chance at survival and passing along genes
Reciprocal non-kin relationships
I'll scratch your back if you scratch mine?
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