Biology: Evolution Key Concepts

Evolution

Overview Evolution is the scientifically supported theory that all species of life have developed from a common ancestor through the process of natural selection, genetic drift, mutation, and gene flow.

Key Concepts

• Natural Selection: The process by which organisms that are better adapted to their environment are more likely to survive and reproduce, passing on their advantageous traits to their offspring.
• Artificial Selection: The intentional breeding of organisms with desired traits, leading to changes in the population over time.
• Speciation: The process by which a new species emerges from an existing one, often as a result of geographic isolation or other mechanisms.

Mechanisms of Evolution

• Mutation: A change in the DNA sequence of an individual, which can result in new traits.
• Genetic Drift: The random change in the frequency of a gene or genetic trait in a population over time.
• Gene Flow: The movement of genes from one population to another, resulting in the exchange of genetic information.

Evidence for Evolution

• Fossil Record: The chronological record of fossilized remains, which shows a pattern of gradual changes in life forms over time.
• Comparative Anatomy: The study of similarities and differences in the body structures of different species, revealing common ancestry.
• Molecular Biology: The study of DNA and protein sequences, which confirms the relatedness of different species.

Types of Evolution

• Microevolution: Small-scale evolutionary changes within a population or species.
• Macroevolution: Large-scale evolutionary changes resulting in the formation of new species or higher taxonomic groups.

Evolutionary Forces

• Selection Pressures: Environmental factors, such as predation, climate, and competition, that influence the survival and reproduction of individuals.
• Genetic Variation: The raw material for evolution, which provides the differences in traits that are acted upon by selection pressures.

Evolution

Key Concepts

• Evolution is the scientifically supported theory that all species of life have developed from a common ancestor through natural selection, genetic drift, mutation, and gene flow.
• Natural Selection: process by which organisms better adapted to their environment survive and reproduce, passing on advantageous traits to their offspring.
• Artificial Selection: intentional breeding of organisms with desired traits, leading to changes in the population over time.
• Speciation: process by which a new species emerges from an existing one, often due to geographic isolation or other mechanisms.

Mechanisms of Evolution

• Mutation: change in an individual's DNA sequence, resulting in new traits.
• Genetic Drift: random change in gene or genetic trait frequency in a population over time.
• Gene Flow: movement of genes from one population to another, exchanging genetic information.

Evidence for Evolution

• Fossil Record: chronological record of fossilized remains, showing gradual changes in life forms over time.
• Comparative Anatomy: study of body structure similarities and differences, revealing common ancestry.
• Molecular Biology: study of DNA and protein sequences, confirming relatedness of different species.

Types of Evolution

• Microevolution: small-scale evolutionary changes within a population or species.
• Macroevolution: large-scale evolutionary changes resulting in new species or higher taxonomic groups.

Evolutionary Forces

• Selection Pressures: environmental factors (predation, climate, competition) influencing individual survival and reproduction.
• Genetic Variation: raw material for evolution, providing differences in traits acted upon by selection pressures.