Evolution and Human Origins Flashcards

Flashcards from lecture notes on evolution and human origins.

Evolutionary Adaptation

Inconspicuous coloration of male guppies in pools containing visual predators.

Natural Selection

Individuals best suited to their environment contribute the most genes to the next generation.

Heritable Trait

A trait that can be acted upon by natural selection.

Hardy-Weinberg Equilibrium

A population where allele frequencies are stable across generations.

Gametic Barrier

An example of a prezygotic isolating mechanism.

Ecological Isolation

Different species utilizing different resources within the same environment.

Artificial Selection

Breeders choosing low- fat variants and crossbreeding them over several generations.

Punctuated Equilibrium Model

Illustrated by an example of adaptive radiation.

Vestigial Structures

Nonfunctional evolutionary baggage.

Evolutionary Fitness

The ability to reproduce and pass genes to the next generation.

Adaptation

A mutation resulting in a heat-resistant enzyme in a bacterium living in a hot spring.

Genetic Drift

Chance events that change allele frequencies in small populations.

Gene Flow

The net migration of alleles into or out of a population from neighboring populations.

Sexual Selection

Male fish that display a bright blue color attract more mates as well as more predators.

Mutations

Provide variation that can result in evolutionary change.

Maximum Parsimony

Similarity due to common ancestry should be more common than similarity due to convergent evolution.

Adaptive Radiation

A species invades a new habitat and evolves rapidly into several new species to better exploit new resources.

Allopatric Speciation

Two species of squirrels live on either side of the Grand Canyon.

Autopolyploidy

The potato could therefore be described as being the result of the process known as.

Directional Selection

Anolis lizards are placed on small islands with no large trees and exhibit shorter hind legs than their ancestors.

Stabilizing Selection

The butterflies in a mountain population become a similar shade of medium gray over the course of several generations.

Orthologous Gene

The same gene in different species.

Transposable Elements

Selfish elements that replicate themselves and move around within a genome.

Bipedal Posture

How hominins differ from all other known great apes.

Melanin

Helps to protect human skin from UV radiation damage, in tropical climates with abundant direct sunlight.

Vitamin D

Nutrient required by pregnant human females for healthy fetal development; degraded by sunlight exposure.

Homo erectus

Stood six feet tall and wandered the world for about a million years beginning close to two million years ago.

Homo naledi

Lived in South Africa around 300,000 years ago; small in stature, with long arms and long fingers.

Homo neanderthalensis

Traces origins to a few hundred thousand years ago on the Eurasian continent.

Ardipithecus ramidus

Lived in an African forest more than four million years ago, where they walked upright but also climbed trees quite well.

Australopithecus afarensis

Lived more than three million years ago in Africa. Walked fully upright. Fossil Specimen is nicknamed 'Lucy'.

Primates

Apes, humans, monkeys, lemurs, and tarsiers because they share grasping hands and feet, forward facing eyes, large brains, & specialized dental patterns.

Monotreme

The platypus and the echidna (spiny anteater) because they are the only modern mammals that lay eggs.

Marsupials

Subgroup of mammals that raises their young in pouches.

Eutherians

Subgroup of mammals that Humans belong to.

Homo neanderthalensis or Neanderthals

When modern humans arrived in Europe at least 40,000 years ago, they found this region already occupied by people called:

Ka/Ks > 1

Positive Selection

Ka/Ks < 1

Negative Selection

Ka/Ks = 1

Neutral Selection