Evolution & Human Systems Lecture Notes

Comprehensive flashcards covering evolution theories, mechanisms, Hardy-Weinberg equilibrium, human evolution, and the skeletal/excretory systems based on Unit 10 lecture notes.

Natural Selection

The mechanism of evolution proposed by Charles Darwin, defined as the unequal survival and reproduction of organisms due to the environment.

Descent with Modification

The principle that species descend from a common ancestor, accumulating changes over time.

Darwin's Finches

Fourteen different species of birds on the Galapagos Islands that evolved different beak shapes and sizes adapted to specific food sources like seeds, insects, or cactus.

Jean Baptiste Lamarck

An early evolutionary theorist who proposed the wrong mechanism of 'acquired characteristics' and 'use and disuse,' suggesting traits developed during an organism's life are passed to offspring.

Fitness

A measure of how well an organism can survive and reproduce; specifically, the more offspring produced, the higher the fitness.

Six Kingdoms of Life

Archaebacteria, Eubacteria, Protista, Plantae, Animalia, and Fungi.

Industrial Melanism

The darkening of a species, such as the Peppered Moth, due to pollutants during the Industrial Revolution which changed the selective pressure for camouflage.

Artificial Selection

Also known as selective breeding, where humans control breeding to produce specific desired traits in offspring.

Homologous Structures

Structures that have the same anatomical origin and provide evidence of a common ancestor, though they may differ in outward appearance and function.

Vestigial Structures

Structures that exist in an organism but have no apparent purpose, providing evidence of common ancestry, such as pelvic bones in snakes and whales.

Similarities in Embryology

Evidence of common ancestry shown through shared developmental traits, such as humans having pharyngeal slits and tails during early development.

Comparative Biochemistry

Genetic evidence for evolution based on the fact that all organisms share DNA, RNA, ATP, and the same 20 amino acids.

Stabilizing Selection

A pattern of natural selection that favors individuals with average values of a trait and selects against extreme values.

Directional Selection

A pattern of natural selection that favors individuals at one extreme of a trait, causing that extreme to become the new average.

Disruptive Selection

A pattern of natural selection that favors individuals at both extremes of a trait and selects against the intermediate values; most likely to lead to speciation.

Speciation

The process by which one species evolves into one or more different species, occurring when gene pool sharing stops.

Divergent Evolution

Evolution where two or more lineages descend from a common ancestor, often resulting in adaptive radiation across varied niches.

Convergent Evolution

The independent evolution of similar structures among unrelated organisms resulting from similar environmental pressures, producing analogous structures.

Coevolution

The evolution of adaptations in two species due to their extensive interactions, often described as an 'evolutionary arms race' between predators and prey.

Punctuated Equilibrium

An evolutionary tempo characterized by long periods of little change followed by brief periods of intense change, accounting for gaps in the fossil record.

Genetic Drift

A mechanism of evolution in which allele frequencies in small populations change due to chance events.

Population Bottleneck

A form of genetic drift where a population becomes extremely small due to a chance event, leading to a loss in genetic variability.

Founder Effect

A form of genetic drift occurring when a new population is founded by a small number of individuals who have different allele frequencies from the original population by chance.

Allopatric Speciation

Speciation that occurs due to separation by a physical barrier that prevents gene flow.

Sympatric Speciation

Speciation that occurs without a physical divide, often due to organisms occupying different niches or sexual selection within a single population.

Gene Flow

The movement of alleles from one population to another due to the migration (immigration or emigration) of individual organisms.

Hardy-Weinberg Equilibrium

A state where a population is not evolving and allele frequencies remain constant; requires a large population, no gene flow, no mutations, random mating, and no natural selection.

Hardy-Weinberg Allele Equation

$p + q = 1$, where $p$ is the frequency of the dominant allele and $q$ is the frequency of the recessive allele.

Hardy-Weinberg Genotype Equation

$p^2 + 2pq + q^2 = 1$, where $p^2$ is the frequency of homozygous dominant individuals, $2pq$ is the frequency of heterozygotes, and $q^2$ is the frequency of homozygous recessive individuals.

Hominidae

The family containing humans and the 'Great Apes' (Orangutans, Gorillas, Bonobos, and Chimpanzees), characterized by bipedalism.

Ardipithecus ramidus

A 4.4 million-year-old fossil known as 'Ardi' found in Ethiopia, predating Lucy.

Australopithecus afarensis

A species that evolved in Africa 4 million years ago; the famous fossil 'Lucy' (3.2 million years old) belongs to this group.

Out of Africa Theory

The hypothesis that Homo sapiens evolved in Africa and then migrated to Asia and Europe.

Neanderthals

Homo sapien neanderthalis, whose DNA is 99.88\text{%} similar to modern humans and who lived in Europe and Asia until going extinct 30,000 years ago.

Melanin Adaptation

Dark skin near the equator protects folic acid from UV destruction, while pale skin at the poles increases Vitamin D synthesis in low-light environments.

Skeletal System

The system made of bone and cartilage tissues that provides support and locomotion, consisting of 206 bones in humans.

Sarcomere

The basic unit of muscle contraction consisting of thin actin filaments and thick myosin filaments.

Nitrogenous Wastes

Metabolic wastes including Ammonia (mostly aquatic animals), Urea (mammals, amphibians, sharks), and Uric Acid (birds, reptiles, insects).

Nephron

The basic unit of filtration in the kidney; each human kidney contains approximately 1 million.

ADH (AntiDiuretic Hormone)

A hormone that causes the walls of the collecting duct to become more permeable to water, allowing water to stay in the body rather than being excreted in urine.