Darwin's Theory of Evolution and Population Genetics

Flashcards covering Darwin's theory of evolution, natural selection, evidence of evolution, population genetics, and the Hardy-Weinberg Principle based on the lecture notes.

Evolution

The process by which modern organisms descended from ancient organisms; change over time.

Charles Darwin

The scientist who developed and spread the theory of natural selection after studying organisms worldwide.

HMS Beagle

The ship Darwin sailed on in 1931 as a naturalist to study and inventory new organisms.

Hutton & Lyell

Scientists who proposed that the Earth is millions of years old and that the processes changing Earth today are the same as those in the past.

Lamarck

One of the first scientists to suggest species change over time, though he incorrectly hypothesized selection occurred via the use and disuse of organs.

Malthus

Writer who argued that unchecked human population growth leads to insufficient food and space, an idea Darwin applied to plants and animals.

Fitness

An organism's ability to survive and reproduce in its environment.

Adaptation

Any characteristic that increases an organism's chance for survival.

On the Origin of Species

The book published by Darwin in 1859 outlining his ideas on evolution and natural selection.

Descent with modification

The principle that species today look different from their ancestors due to natural selection over time.

Homologous body structures

Parts of different organisms that come from the same embryonic tissue but have a different mature form, such as the arm of a human and the wing of a bat.

Vestigial organs

Small, reduced traces of an organ that no longer function, such as the human appendix or tail bone.

Cladograms

Visual diagrams showing the evolutionary relationship between different organisms based on scientific evidence.

Population

A group of individuals of the same species that live in the same area at the same time.

Gene pool

All the genes (alleles) of a population of organisms.

Relative frequency

The percentage of a particular allele in a population's gene pool.

Directional Selection

A type of natural selection where individuals at one end of the spectrum have a higher fitness than those in the middle or at the other end.

Stabilizing Selection

A type of natural selection where individuals near the center of the spectrum have a higher fitness than those at either end.

Disruptive Selection

A type of natural selection where individuals at either end of the spectrum have a higher fitness than those in the middle.

Genetic Drift

Random, unpredictable changes in allele frequency that are more likely to occur in small populations.

Founder Effect

A form of genetic drift that occurs when a small population colonizes a new area.

Hardy-Weinberg Principle

The principle stating that allele frequency in a population will remain stable (genetic equilibrium) unless acts of evolutionary force occur.

Hardy-Weinberg Equation

$$p^2 + 2pq + q^2 = 1$$

p

The relative frequency of the dominant allele in a gene pool.

q

The relative frequency of the recessive allele in a gene pool.

$$p^2$$

The percentage of homozygous dominant organisms in a gene pool.

$$2pq$$

The percentage of heterozygous organisms in a gene pool.

$$q^2$$

The percentage of homozygous recessive organisms in a gene pool.

Speciation

The development of new species from existing species.

Reproductive Isolation

When organisms in a species can no longer mate, leading to the development of two separate species.

Behavioral Isolation

Isolation caused by differences in mating habits or rituals that prevent species from interbreeding.

Geographic isolation

Isolation caused by a physical barrier that prevents organisms from mating.

Temporal (Seasonal) Isolation

Isolation that occurs when organisms mate at different times of the day or in different seasons.

Macroevolution

Large-scale evolutionary patterns and processes that occur over long periods of time, such as extinction.