Biology: Evolution and Descent with Modification

Definition and Overview

• Evolution: 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
• Describes the change in the inherited characteristics of a population of organisms over time

Key Principles

• Descent with modification: all living organisms share a common ancestor and have evolved over time through the accumulation of genetic changes
• Variation: all individuals within a population exhibit genetic variation, which provides the raw material for evolution
• Heritability: the characteristics of an individual are determined by their genetic makeup, which is passed on to their offspring
• Adaptation: the process by which a population becomes better suited to its environment, leading to increased survival and reproductive success

Mechanisms of Evolution

• Natural Selection:
  • Differential reproduction: individuals with advantageous traits are more likely to survive and reproduce, passing their traits to their offspring
  • Selection pressures: environmental factors that affect an individual's ability to survive and reproduce
• Genetic Drift: random events that change the frequency of a gene or genetic trait in a population
• Mutation: changes in the DNA sequence of an individual, which can result in new traits or changes to existing traits
• Gene Flow: the movement of genes from one population to another, leading to changes in the gene pool

Evidence for Evolution

• Fossil Record: the chronological record of the history of life on Earth, which shows a clear pattern of gradual changes in life forms over time
• Comparative Anatomy: the study of the structure and development of living organisms, which reveals similarities and homologies between different species
• Molecular Biology: the study of DNA and protein sequences, which shows significant similarities between different species
• Biogeography: the study of the geographic distribution of living organisms, which shows a pattern of related species being found in the same or nearby locations

Evolutionary Processes

• Speciation: the process by which a new species emerges from an existing one
• Co-evolution: the process by which two or more species evolve in response to each other
• Macroevolution: the study of large-scale evolutionary changes, such as the origin of new body plans or the emergence of new phyla
• Microevolution: the study of small-scale evolutionary changes, such as changes within a population or species

Definition and Overview

• Evolution is the scientifically supported theory that all species of life developed from a common ancestor through natural selection, genetic drift, mutation, and gene flow.
• Evolution describes the change in inherited characteristics of a population of organisms over time.

Key Principles

• Descent with modification: all living organisms share a common ancestor and have evolved over time through genetic changes.
• Variation: all individuals within a population exhibit genetic variation, providing the raw material for evolution.
• Heritability: characteristics of an individual are determined by their genetic makeup, passed on to their offspring.
• Adaptation: the process by which a population becomes better suited to its environment, leading to increased survival and reproductive success.

Mechanisms of Evolution

• Natural Selection:
  • Differential reproduction: individuals with advantageous traits are more likely to survive and reproduce.
  • Selection pressures: environmental factors affecting an individual's ability to survive and reproduce.
• Genetic Drift: random events changing the frequency of a gene or genetic trait in a population.
• Mutation: changes in an individual's DNA sequence, resulting in new traits or changes to existing traits.
• Gene Flow: the movement of genes from one population to another, leading to changes in the gene pool.

Evidence for Evolution

• Fossil Record: a chronological record of life on Earth, showing gradual changes in life forms over time.
• Comparative Anatomy: similarities and homologies between different species reveal their evolutionary relationships.
• Molecular Biology: DNA and protein sequences show significant similarities between different species.
• Biogeography: the geographic distribution of living organisms reveals patterns of related species in the same or nearby locations.

Evolutionary Processes

• Speciation: the process by which a new species emerges from an existing one.
• Co-evolution: the process by which two or more species evolve in response to each other.
• Macroevolution: the study of large-scale evolutionary changes, such as the origin of new body plans or emergence of new phyla.
• Microevolution: the study of small-scale evolutionary changes, such as changes within a population or species.

Explore the fundamental principles of evolution, including descent with modification, variation, and the change in inherited characteristics of a population over time.