Unit 5

Evolution

Biological Evolution

• All of the changes that have transformed life on Earth from the earliest beginnings to the diversity of organisms in the world today

Microevolution

• Change in a single, small population

Macroevolution

• Change in many large populations

Natural Selection

• States that the organisms that are fit to adapt to a changing environment will survive and pass those traits on to their offspring; but the organisms that cannot adapt will die

Overproduction of Offspring

• When too many offspring are produced that the environment will support

Variation

• A change in the offspring that is different from the parents

Inherited Traits

• Traits that are passed down from the parents to the offspring

Adaptation

• When organisms change to survive in an environment

Fitness

• Desired traits that allow the organism to survive

Survival of the Fittest

• Natural Selection that states that the organism that can adapt to a changing environment will survive and others will die

Descent with Modification

• When acquired traits are passed down to offspring

Species

• Organisms that are similar and can interbreed with one another

Gene Pool

• All genes in a population

Genetic Variability

• When a new generation results in individuals with unique genotypes and phenotypes

Genetic Drift

• The random change in the frequency of alleles of a population over time

Gene Flow

• The movement of genes into or out of a population

Non-Random Mating

• When mates are selected from a specific group within the species

Genetic Equilibrium (Hardy-Weinberg Principle)

• When there is no change in the allele frequencies within a species

Speciation

• The process of forming a new species by biological evolution from a preexisting species

Patterns of Evolution

• Describes the changes in evolution

Gradualism

• Gradual changes of a species in a particular way over long periods of time

Punctuated Equilibrium

• Periods of abrupt changes in a species after long periods of little change within the species over time, such as sudden change in species size or shape due to environmental factors

Adaptive Radiation/divergent Evolution

• When a number of different species split-off from a common ancestor

Convergent Evolution

• Evolution among different groups of organisms living in similar environments produces species that are similar in appearance and behavior (analogous structures)

Coevolution

• When two or more species living in close proximity change in response to each other

Gradual Extinction

• Extinction that occurs at a slow rate and may be due to other organisms, changes in climate, or natural disasters

Mass Extinction

• Extinction that occurs when a catastrophic event changes the environment very suddenly (such as a massive volcanic eruption, or a meteor hitting the earth causing massive climatic changes)

Anatomy

• The study of the structures of organisms

Homologous Structures

• Similar characteristics resulting from common ancestry

Vestigial Organs

• Structures with little or no function to the organism that are remnants of structures that had important functions in ancestors of the species

Embryology

• The study of the embryonic development of organisms

Biochemistry

• The study of the chemical processes in organisms

Paleontology

• The study of prehistoric life

Phylogeny

• Evolutionary history of a species or a group of related species

Convergence

• Structures that become more similar with time, which occurs when organisms with different evolutionary histories adapt to similar environments

Evolutionary Data

• Information derived from studying prehistoric remains

Transitional Fossils

• Fossils that show links in traits between groups of organisms and used to document intermediate stages in the evolution of a species

Phylogenetic Tree

• A scientific diagram that biologists use to represent the evolutionary history of organisms

Taxa

• Groups that are based on evolutionary relationships