B unit 1

Evolution

Change in appearance or behavior of organisms over time; change in allele frequency in a population over time.

James Hutton

Scottish geologist who proposed gradual changes in rocks and landscape.

Charles Lyell

Friend of Darwin who suggested the Earth is old and changes occur gradually.

Jean-Baptiste Lamarck

Proposed the inheritance of acquired characteristics, such as the incorrect example of a giraffe's long neck developing by stretching to reach leaves.

Natural Selection

Process where advantageous traits are passed down due to better survival, as observed in Darwin's finches.

Key Observations of Natural Selection

1. Traits are inherited. 2. More offspring are born than can survive (competition). 3. Offspring differ in traits.

Natural Selection Example with Galapagos Finches

The work of Rosemary and Peter Grant showed that a drought in 1977 favored birds with larger beaks for food.

Sexual Selection

A type of natural selection influenced by mate choice, involving male-male competition and female choice.

Male-Male Competition

A situation in sexual selection where males compete for access to females.

Female Choice

A preference where females select males based on attractive traits, such as bright feathers.

Benefit of Sexual Selection

Healthy males are more likely to pass on good alleles.