Ch 2

Evolutionary theory

The concept that living species can change over time and give rise to new species, sharing a common ancestry.

Evolution

The material evidence of change over time, exemplified by the fossil record.

Darwin's finches

A case study illustrating how beak sizes varied based on food availability in different environments.

Pre-Darwinian Views

The belief that the world was fixed and unchanging.

Essentialism

The belief in fixed, perfect ideas that exist eternally, with actual objects being imperfect realizations of these ideals.

Great Chain of Being

A hierarchical framework based on Aristotle's principles, linking all living organisms in a divinely created chain.

Taxonomy

The classification of various kinds of organisms in biology.

Genus

A group of different species classified based on similarities.

Species

A reproductive community of populations occupying specific niches in nature.

Catastrophism

The theory that species were abruptly wiped out and replaced by new species due to natural disasters.

Uniformitarianism

The principle that current processes can be used to understand the past history of the Earth.

Lamarck’s Viewpoint

The idea that species can change physically in response to environmental changes over time.

Transformational evolution

A concept where individual members of a species transform to meet environmental challenges.

Darwin and Wallace discoveries

The conclusion that all species share a common ancestor.

Natural Selection

The process by which variant individuals best suited to their environment survive and reproduce.

Variational evolution

The concept that different variants of a species respond differently to environmental challenges.

Three principles of Darwinian evolution

Variation, heredity, and natural selection.

Adaptation

A useful feature of an organism shaped by natural selection.

Exaptation

A feature originally shaped by natural selection for one purpose, later adapted for a different function.

Pangenesis

A theory suggesting traits are passed on through distinct particles from all parts of an organism.

Mendelian Inheritance

The concept of non-blending, single-particle genetic inheritance.

Principle of Segregation

Each individual receives one gene for each trait from each parent.

Principle of Independent Assortment

Genes separate independently during the formation of germ cells.

Genetics

The scientific study of biological heredity.

Homozygous

A fertilized egg that receives the same particle from both parents for a trait.

Heterozygous

A fertilized egg that receives different particles from each parent for the same trait.

Gene

The basic unit of heredity, referring to particles.

Alleles

Different forms that genes can take.

Chromosomes

Structures in the cell nucleus made of DNA that contain hereditary information.

Mitosis

The process by which body cells replicate themselves.

Meiosis

The process by which sex cells replicate, resulting in a single set of chromosomes.

Locus

The specific location of a gene on a chromosome.

Linkage

The inheritance pattern where unrelated traits occur together due to being on the same chromosome.

Crossing over

The exchange of genetic material between chromosomes during meiosis.

Discontinuous variation

A pattern of phenotypic variation with sharp breaks between individuals.

Polygeny

The concept that multiple genes influence a single phenotypic trait.

Continuous variation

A pattern of variation where traits grade imperceptibly without sharp breaks.

Pleiotropy

A single gene affecting multiple phenotypic traits.

Mutation

The alteration of DNA that creates new alleles.

DNA

The molecule carrying genetic information and instructions for protein synthesis.

Genome

The total genetic material within a cell nucleus.

Norm of Reaction

A graph displaying phenotypic outcomes for a genotype in different environments.

Niche Construction

The process by which organisms modify their environment, affecting selection pressures.

Human agency

The capacity of individuals to exert control over their lives, influencing evolutionary dynamics.