Biology Evolution

Disruptive Selection

Disruptive Selection

form of natural selection in which a single curve splits into two; occurs when individuals at the upper and lower ends of a distribution curve have higher fitness than individuals near the middle

Directional Selection

occurs when natural selection favors one of the extreme variations of a trait

Stabilizing Selection

form of natural selection by which the center of the curve remains in its current position; occurs when individuals near the center of a distribution curve have higher fitness than individuals at either end

Coevolution

Process by which two species evolve in response to changes in each other

Parasite Host

a relationship where one organism benefits and the other is harmed

Prey and Predator

when one animal (the predator) eats another living animal (the prey) to utilize the energy and nutrients from the body of the prey

Competitive Species

when two species compete for the same food source ; same niche

Mutualistic

both organisms benefit

Comparative Anatomy

The comparison of body structures and how they vary among species

Vestigial Structures

remnant of a structure that may have had an important function in a species' ancestors, but has no clear function in the modern species.

Analogous Structures

Body parts that share a common function, but not structure

Homologous Structures

Structures in different species that are similar because of common ancestry.

Biogeography

Study of past and present distribution of organisms

Comparative Embryology

the study of the similarities and differences in the embryos of different species

Fossil Record

information about past life, including the structure of organisms, what they ate, what ate them, in what environment they lived, and the order in which they lived

Biochemistry

the study of substances and processes occurring in living things

Darwin

English natural scientist who formulated a theory of evolution by natural selection (1809-1882)

Lamarck

French naturalist who proposed that evolution resulted from the inheritance of acquired characteristics (1744-1829)

Carl Linnaeus

"Father of Taxonomy"; established his classification of living things; famous for animal naming system of binomial nomenclature

Miller - Urey

Miller and Urey were scientists who, in 1953, simulated the conditions of primitive Earth in a laboratory. They put the gases theorized to be abundant in the early atmosphere into a flask, struck them with electrical charges in order to mimic lighting, and organic compounds similar to amino acids appeared.

Oparin- Haldane

Oparin and Haldane were two scientists who proposed in the 1920s that the primitive atmosphere contained the following gases: methane, ammonia, hydrogen, and water. They believed that these gases collided, producing chemical reactions that eventually led to organic molecules.

Natural Selection

thumb ; Alleles that are better for the species will continue in offspring, and alleles not good for the species will not

Gene flow

pointer ; Immigration and emigration between a population, changing alleles in the population

Mutation

middle finger ; Only mutations in sex cells are basis for evolution

Non-random mating

ring finger ; organisms mate specifically for the survival of the species

Genetic Drift

pinky ; migration from one population to another

The Founder Effect

change in allele frequencies as a result of the migration of a small subgroup of a population

Bottleneck Effect

A change in allele frequency following a dramatic reduction in the size of a population

Taxonomy

The scientific study of how living things are classified

Domain

Most inclusive taxonomic category; larger than a kingdom

Kingdom

large taxonomic group, consisting of closely related phyla

Phylum

in classification, a group of closely related classes

Class

Mammalia

Order

in classification, a group of closely related families

Family

Group of genera that share many characteristics

Genus

A classification grouping that consists of a number of similar, closely related species

Species

A group of similar organisms that can breed and produce fertile offspring.

Allopatric speciation

The formation of new species in populations that are geographically isolated from one another.

Sympatric speciation

The formation of new species in populations that live in the same geographic area

Geographic barriers/isolation

physical/geographic barrier separates a population and its gene pool

Temporal Isolation

form of reproductive isolation in which two populations reproduce at different times

Reproductive Isolation

Separation of species or populations so that they cannot interbreed and produce fertile offspring

Behavioral isolation

isolation between populations due to differences in courtship or mating behavior

Relative Dating

Method of determining the age of a fossil by comparing its placement with that of fossils in other layers of rock

Radiometric Dating

method used to determine the age of rocks using the rate of decay of radioactive isotopes

Adaptive Radiation

An evolutionary pattern in which many species evolve from a single ancestral species

Gradualism

The theory that evolution occurs slowly but steadily

Punctuated Equilibrium

The theory that species evolve during short periods of rapid change

Bacterial conjugation

The transfer of plasmids between bacterial cells by direct cell-to-cell contact or by a bridge-like connection between two cells.

Antibiotic resistance

the ability of bacteria to withstand the effects of an antibiotic

Miller-Urey experiment

Two scientists attempted to reproduce the condition of the (assumed) earth's primitive ocean's under a reducing atmosphere. They produced some of the key molecules to life (amino acids and nucleotides).

Ribozyme

An RNA molecule that functions as an enzyme, such as an intron that catalyzes its own removal during RNA splicing.

RNA World Hypothesis

Hypothesis that describes how the Earth may have been filled with RNA-based life before it became filled with the DNA-based life we see today.

Earth's History

Hot atmosphere ; no protection from UV radiation ; amino acids, sugars, nitrogenous bases, glycerol ; methane and ammonia in atmosphere

Primordial soup

theory that the early oceans were a solution of organic molecules

Endosymbiosis theory

A theory that mitochondria and chloroplasts originated from bacteria that took up residence within a primordial eukaryotic cell.

Genetic polymorphism

The existence of two or more distinct alleles at a given locus in a population's gene pool.

Gene pool

All the genes, including all the different alleles for each gene, that are present in a population at any one time

BInomial nomenclature

Classification system in which each species is assigned a two-part scientific name