Biodiversity on Earth

Diversity of Life on Earth

• Biodiversity refers to the variety of different species, genetic diversity, and variation within species.

Species Diversity

• Refers to different species living in the same area.

Genetic Diversity

• Refers to different genetic makeup within the same species.

Variation

• Individuals within a species exhibit variations, which can arise from:
  • Genes and chromosomes inherited from parents
  • Genetic mutations
  • Environmental factors
• Variations that help an organism survive are called adaptations.

Adaptations

• Physical, functional, or behavioral traits that enable an organism to survive and breed in its environment.
• Adaptations are inherited and can be:
  • Structural (physical structure)
  • Functional (internal process)
  • Behavioral (way an animal acts)

What is a Species?

• A species consists of individuals that can interbreed to produce fertile offspring.

What is a Theory?

• A theory is an explanation about the natural world that can be tested and verified using the scientific method.

The Theory of Evolution

• Evolution is the change in inherited traits of a population over generations through natural selection.

Natural Selection

• The process by which the environment selects favorable traits and reduces unfavorable traits, relying on:
  • Variation (essential for natural selection)
  • Selection (environmental pressures)
  • Heredity (traits are passed on through generations)

Variation within Populations

• Genetic diversity within a population can be affected by:
  • Genetic drift (chance events)
  • Genetic flow (emigration and immigration)

Selection

• Environmental pressures, such as biotic and abiotic factors, determine which variations provide an advantage for survival.

Competition

• Individuals within a population compete for resources, and those with advantageous variations are better suited to obtain resources and survive.

Observing Evolution

• Natural selection takes several generations to produce noticeable changes.

Speciation

• The formation of a new species through geographic isolation, natural selection, and reproductive isolation.

Types of Evolution

• Variations on speciation and different evolutionary paths.