Evolution and Natural Selection Flashcards

Flashcards covering the fundamental concepts of evolution, natural selection, speciation, and the evidence supporting evolutionary theory as presented in the lecture notes.

Variations

A difference in traits between individuals of the same species, which is necessary for a population to evolve.

Phenotypes

The observable characteristics or what we see in an individual organism.

Genotypes

The specific genes carried by members of a population.

Acquired trait

A feature gained during an individual's lifetime, such as a tattoo or an artificial change in hair color, that is not passed down by genes.

Genetic trait

A feature determined by genes in an individual's DNA and passed down from one generation to the next, such as eye color or beak shape.

Mutations

Small random changes in the DNA sequence that produce new alleles and variations in traits.

Evolution

Any change in the genetic traits in a population over many generations.

Genetic diversity

The amount of genetic variation within a population; higher diversity increases the likelihood of species survival during environmental changes.

Darwinism

The evolutionary theory proposed by Charles Darwin suggesting that species develop through the natural selection of small, inherited variations.

Natural selection

The process where individuals with advantageous traits survive longer and reproduce more successfully, passing those traits to offspring.

Jean Baptiste de Lamarck

The first to propose that change over time resulted from natural phenomena, though his belief that acquired traits could be inherited was later discredited.

Descent with modification

Darwin's view that descendants of ancestral forms adapted to different environments over long periods of time.

Overproduction

A principle of natural selection where a species produces more offspring than will survive to reproductive age.

Survival of the fittest phenotype

The concept that individuals with the most favorable combinations of characteristics are most likely to survive and pass on their genes.

Reproductive advantage

A condition where each new generation contains more offspring from individuals with favorable characteristics while unfavorable ones decrease.

Species

Any group of organisms that can breed to produce fertile offspring.

Speciation

The biological process involving variation, isolation, and selection that leads to the formation of a new species.

Splitting

A form of speciation where a species divides fairly equally into two populations that evolve differently until they become separate species.

Budding

A form of speciation where a small part of a species population evolves rapidly to form a new species while the original population remains mostly unchanged.

Transitional feature

A fossilized intermediate state between an ancestral trait and that of its later descendants, such as the features found in Archaeopteryx.

Pakicetus

A land-dwelling relative of ancient whales with nostrils at the front of the skull, representing an ancestral form in whale evolution.

Homologous structures

Body parts similar in structure but potentially different in function, such as the forelimbs of humans, whales, and bats, indicating common ancestry.

Pentadactyl limb

A homologous structure found in vertebrates that provides evidence for evolution from a single vertebrate ancestor.

Cytochrome c

A protein found in all living organisms used by scientists to compare amino acid sequences and determine how closely related two species are.

Biogeography

The study of the distribution of lifeforms over geographical areas, which suggests that closely distributed species share a common lineage.

Phylogenetic tree

A diagram showing evolutionary relationships where branches represent lineages and nodes represent common ancestors based on DNA comparisons.