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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