BIO

Biology

The scientific study of life and living organisms.

Materialism

The idea that natural phenomena have physical causes that can be studied.

Methodological Naturalism

Science explains events using natural causes without invoking the supernatural.

Philosophical Naturalism

The belief that only natural things exist.

Adaptation

A heritable trait that increases survival or reproduction.

Fitness

An organism's reproductive success relative to others.

Descent with Modification

Species change over generations and share common ancestry.

Natural Selection

Individuals with advantageous traits leave more offspring.

Historical Constraint

Evolution is limited by a species' evolutionary history.

Aristotle

Ancient Greek philosopher who promoted the "Ladder of Life."

Ladder of Life

Linear ranking of organisms from simple to complex.

Great Chain of Being

Medieval idea that all organisms occupy fixed positions in nature.

Scala Naturae

Latin term for Aristotle's Ladder of Life.

Aquinas

Theologian who integrated Christian beliefs with Aristotelian philosophy.

Natural Theology

Studying nature to understand divine design.

Paley

Philosopher who proposed the watchmaker argument.

Watch Analogy

Complex structures imply a designer, like a watch implies a watchmaker.

Argument from Design

Claim that biological complexity indicates intelligent design.

Teleological Argument

Explanation based on purpose or design.

Hume

Philosopher who criticized design arguments.

Hume’s Three Objections

Analogy between organisms and machines is weak. Imperfect designs suggest imperfect designers. Multiple designers could explain complexity

Lyell

Geologist who promoted uniformitarianism.

Lamarck

Proposed inheritance of acquired characteristics.

Darwin

Developed evolution by natural selection.

Beagle

Ship on which Darwin traveled.

Malthus

Argued populations grow faster than resources.

Artificial Selection

Human

Natural Selection

Environment determines which traits increase survival and reproduction.

Struggle for Existence

Competition for limited resources.

Wallace

Independently conceived natural selection.

Mayr

Evolutionary biologist who helped define the biological species concept.

Homology

Similarity due to common ancestry.

Biogeography

Study of species distributions.

Law of Succession

Fossil species resemble living species in the same region.

Transitional Fossil

Fossil with traits intermediate between ancestral and derived groups.

Cetacean Example

Fossil evidence showing whale evolution from terrestrial mammals.

Allele

Alternative version of a gene.

Genotype

Genetic makeup of an organism.

Dominant

Allele expressed when present.

Recessive

Allele expressed only when homozygous.

Hardy Weinberg Theorem

Allele frequencies remain constant if evolutionary forces are absent.

Homozygous Dominant

Two dominant alleles (AA).

Homozygous Recessive

Two recessive alleles (aa).

Heterozygous

Two different alleles (Aa).

Large Population Size

Minimizes random changes.

Random Mating

Individuals mate without preference.

No Selection

Equal reproductive success.

No Mutation

No new alleles arise.

No Migration

No gene flow.

Genetic Drift

Random changes in allele frequencies.

Bottleneck Effect

Sharp reduction in population size causes loss of variation.

Founder Effect

New population started by a few individuals.

Inbreeding

Mating among relatives.

Assortative Mating

Individuals choose mates with similar traits.

Migration (Gene Flow)

Movement of alleles among populations.

Directional Selection

Favors one extreme phenotype.

Disruptive Selection

Favors both extremes.

Diversifying Selection

Another term for disruptive selection.

Stabilizing Selection

Favors intermediate phenotypes.

Sexual Selection

Traits increase mating success.

Point Mutation

Single nucleotide change.

Indel

Insertion or deletion of DNA.

Duplication

Copying of a DNA segment.

Polyploidy

Extra complete chromosome sets.

Recombination

Mixing of genetic material during meiosis.

Biological Species Concept

Species are populations that interbreed and produce fertile offspring.

Reproductive Cohesion

Gene flow unites members of a species.

Reproductive Isolation

Prevents gene flow between species.

Habitat Isolation

Different habitats.

Temporal Isolation

Different breeding times.

Behavioral Isolation

Different courtship behaviors.

Mechanical Isolation

Reproductive structures incompatible.

Gametic Isolation

Sperm and egg cannot fuse.

Reduced Hybrid Viability

Hybrids survive poorly.

Reduced Hybrid Fertility

Hybrids are sterile.

Hybrid Breakdown

Later generations have reduced fitness.

Allopatry

Speciation through geographic separation.

Sympatry

Speciation without geographic separation.

Allopolyploidy

Speciation through hybridization and chromosome doubling.

Law of Superposition

Older rock layers lie beneath younger ones.

Radiometric Dating

Determining age using radioactive decay.

Half Life

Time required for half of a radioactive isotope to decay.

Extinction

Permanent disappearance of a species.

Permian Extinction

Largest mass extinction event (~252 million years ago).

Cretaceous

Paleogene Extinction

Chicxulub

Impact crater linked to the K

EVO

DEVO

Allometry

Different growth rates of body parts.

Heterochrony

Evolutionary change in developmental timing.

Homeosis

One body structure develops as another.

Homeotic Gene

Gene controlling body

Homeobox (HOX)

Conserved DNA sequence in developmental genes.

Pitx1 Example

Gene involved in pelvic reduction in stickleback fish.

Linnean Hierarchy

Kingdom, Phylum, Class, Order, Family, Genus, Species.

Binomial Nomenclature

Two

Phylogeny

Evolutionary history of organisms.

Monophyly (Monophyletic Group)

Ancestor and all descendants.

Non monophyly

Group excludes descendants or combines unrelated organisms.