descent with modification/naturalization

Descent with modification

All organisms descend from a common ancestor with modifications.

Tree of life

Darwin viewed the history of life as a tree, with branches representing the diversity of life.

Natural selection

Darwin proposed natural selection as the mechanism for evolution, using artificial selection as evidence.

Artificial vs

Artificial selection involves humans selecting traits, while natural selection is driven by environmental pressures.

Observation 1

Individuals vary greatly in their inherited traits.

Heritable Traits

Natural variation within a species means that some traits are heritable, while acquired traits are not.

Observation 2

Species produce more offspring than their environment can support.

Influence of Malthus

Thomas Malthus influenced Darwin by showing that not all individuals survive due to limited resources.

Survival of the fittest

Individuals with certain traits have greater survival and reproduce more.

Spread of Traits

Selected traits that enhance survival spread through the population.

Adaptation

An adaptation is an inherited characteristic that enhances survival and reproduction in a specific habitat.

Inference 1

Individuals whose traits increase survival tend to have more offspring.

Inference 2

This will lead to the accumulation of favorable traits in the population.

Fitness

Natural selection is the survival of the fittest, where fitness is determined by the number of offspring.

Relative Fitness

Relative fitness is measured by the number of offspring that survive to reproduce.

Dynamic Nature

Natural selection is dynamic, meaning the best trait can change over time.

Fitness Variability

Fitness is not static; for example, larger or smaller bills may be favored depending on the environment.

Evolution in Populations

Populations evolve over time, but individuals do not evolve.

Heritability

Natural selection can only amplify or diminish heritable traits, not acquired traits.

Environmental Variation

Environmental factors vary, so a trait that is favorable in one place may be detrimental in another.

Speciation

Natural selection can drive speciation, the formation of new species.

Lack of Intent

The process of natural selection is not intentional; individuals cannot try to be taller or stronger.

Survival and Reproduction

Natural selection favors traits that improve survival and reproduction in a given environment.

Generational Evolution

Populations evolve over generations, accumulating small changes over time.

Variation

Natural selection acts on existing variation within a population.

Survival and Reproduction Definition

The concept of survival of the fittest refers to the ability to survive and reproduce.

Environmental Pressures

Environmental pressures can cause changes in traits over time.

Speciation Process

Speciation occurs when populations of a species become isolated and evolve independently.

Artificial Selection Examples

Darwin used examples of artificial selection, like dog breeding, to explain natural selection.

Trait Utility

A trait favorable for one species might be useless for another in a different environment.

Raw Material for Evolution

Variation in a population is the raw material for evolution by natural selection.

Selection of Traits

Natural selection does not create new traits; it selects for existing traits that are beneficial.

Extinction

The process of natural selection can lead to the extinction of species that are not well-adapted.

Reproductive Success

Traits that enhance reproductive success tend to increase in frequency over time.