bio1114 Test 1

Fossils

The preserved remains of past life on earth

Paleontologist

A scientist who studies fossils

Radiometric dating

A common way to estimate the age of a fossil by analyzing the elemental isotopes within the accompanying rock

Half-life

The length of time required for a radioisotope to decay to exactly one-half of its initial quantity

Geological timescale

The time line of the earths history and major events from its origin (4.55 bya) to the present

Extinction

The complete loss of a species or group of species

Continental drift

The process by which landmasses have shifted their positions, shapes, and separated

Mass extinction

When many species become extinct at the same time

Heterotroph

Organisms that cannot produce their own organic molecules and thus must obtain organic food from other organisms

Autotroph

Organisms that have metabolic pathways that use energy from inorganic molecules or light to make organic molecules

Stromatolite

A layered calcium carbonate structure in an aquatic environment generally produced by Cyanobacteria

Cambrian explosion

The diversity of animal species increased rapidly during the Cambrian period

Hominoids

Group of primates that include gibbons, orangutans, gorillas, chimps, and humans

Evolution

A heritable change in one or more characteristics of a population from one generation to the next

Microevolution

Changes in a single gene or allele frequencies in a population over time

Macro evolution

The formation of a new species or groups of related species

Species

A group of related organisms that share a distinct form

Population

All members of a species that live in the same area at the same time and have the ability to produce viable and fertile offspring

Empirical thought

Thoughts that rely on observation rather than a spiritual point of view

Inheritance of acquired characteristics

Hypothesis that stated behavioral changes could modify traits and those modified traits were inherited by offspring

Natural selection

Individuals with heritable traits that make the better suited to their environment tend to flourish and reproduce

Transitional form

An organism that provides a link between earlier and later forms in evolution

Biogeography

The study of the geographic distribution of extinct and living species

Endemic species

Organisms that are naturally found only in a particular location

Convergent Evolution

Two species from different lineages have independently evolved similar characteristics because they occupy similar environments

Analogous Structures

A structure that is the result of convergent evolution

Artificial selection

Programs and procedures designed to modify traits in domesticated species

Homology

A similarity that occurs due to descent from a common ancestor

Homologous structures

Structures that are similar to each other because they are derived from a common ancestor

Vestigial structures

Anatomical features that have no current function but resemble structures of their presumed ancestors

Molecular homologies

Similarities between organisms at the molecular level due to descent from a common ancestor

Population genetics

The study of genes and genotypes in a population

Gene pool

All the alleles for every gene in a given population

Allele frequency

The number of copies of a particular allele in a population divided by the total number of alleles in that population

Genotype frequency

In a population the number of individuals with a given genotype divided by the total number of individuals

Hardy Weinberg equation

p+q=1

P²+2pq+q²=1

Adaptations

The processes and structures by which organisms douse ti changes in their environment

Reproductive success

The likelihood of an individual contributing fertile offspring to the next generation

Fitness

The relative likelihood that one genotype will contribute to the gene pool of the next generation

Mean fitness of the population

The average reproductive success of members of a population

Directional selection

Individuals at one extreme of a phenotypic range have greater reproductive success in a particular environment

Stabilizing selection

Type of natural selection that favors the survival of individuals with intermediate phenotypes and selects against this with extreme phenotypes

Diversifying selection

Type of natural selection that favors the survival of two or more different genotypes that produce different phenotypes

Balancing selection

Type of natural selection that maintains genetic diversity in a population

Balanced polymorphism

Two or more alleles are kept in balance and therefore are maintained in a population over many generations

Heterozygote advantage

When a heterozygote has a higher fitness that either corresponding homozygote

Negative frequency dependent selection

When the fitness of a genotype decreases when its frequency becomes higher

Sexual dimorphism

A significant difference between the appearances of the two sexes within a species

Sexual selection

A type of natural selection resulting from variation in the ability to obtain mates

Intrasexual selection

The members of one sex directly compete for the opportunity to mate with individuals of the opposite sex

Intersexual selection

Members of one sex choose their mates from individuals if the other sex on the basis of certain desirable characteristics

Genetic drift

Changes in allele frequencies due to random change

Bottleneck effect

A situation in which a population size is dramatically reduced and then rebounds

Founder effect

When a small group of individuals separates from a larger population and establishes a colony in a new location

Gene flow

When individuals move between populations having different allele frequencies

Nonrandom mating

Individuals choose their mates based in their genotypes or phenotypes

Inbreeding

The mating of two genetically related individuals

Inbreeding depression

When inbreeding produces homozygotes that are less fit thereby decreasing the reproductive success of a population

Taxonomy

The science of describing, naming, and classifying extant and extinct species

Systematics

The study of biological diversity and the evolutionary relationships among extant and extinct species

Extinct

When all members of a species have died

Extant

Species that are still alive today

Taxon

A group of species that are evolutionarily related to each other

Taxonomic hierarchy in order

Domain, super group, kingdom, phyla, classes, orders, families, genera, species

Binomial nomenclature

The standard method for naming a species where every species has a genus name and species epithet

Phylogeny

Rene evolutionary history of a species or group of species

Phylogenic tree

A diagram that describes the evolutionary relationships among various species

Anagenesis

A species is transformed into a different species over the course of many generations

Cladogenesis

A species is divided into two or more species

Nodes

The branch points in a phylogenetic tree

Clade

A group of species derived from a single common ancestor

Monophyletic

A taxon that is a clade

Paraphyletic groups

A common ancestor and some, but not all, of its descendants

Polyphyletic groups

Members of several evolutionary lines and does not include the most recent common ancestor of the included lineages

Molecular systematics

Analysis of genetic data, such as DNA sequences or amino acid sequences, to identify and study genetic homologies and propose phylogenetic trees

Cladistics

The classification of species based on evolutionary relationships

Cladogram

A phylogenetic tree constructed by using a cladistics approach

Characters

Homologous features

Character states

A particular variant of a given character

Selected primitive character (Symplesiomorphy)

A character that is shared by two or more different taxa and inherited from ancestors older than their last common ancestor

Shared derived character (Synapomorphy)

A character that is shared by two or more species or taxa and has originated in their most recent common ancestor

Ingroup

The group whose evolutionary relationships we wish to understand

outgroup

A species or group of species that is assumed to have diverged before the species of the ingroup

Principle of parsimony

States that the preferred hypothesis is the one that is the simplest for all the characters and their states

Maximum likelihood

An approach that states neutral mutation are more likely to be conserved than nonneutral mutations and that the rate of change of DNA sequence is relatively constant between generations