IB Biology D4.1 Natural Selection

These flashcards cover key concepts in natural selection, including definitions, mechanisms, and examples as presented in IB Biology D4.1 lecture.

Natural Selection

The process where individuals with advantageous traits survive and reproduce more than others.

Core Postulates of Natural Selection

Variation, overproduction, struggle/selection, inheritance.

Gene Pool

The total collection of alleles in a population that evolves through allele frequency changes.

Fitness

The reproductive success of an individual relative to others in a population, influenced by adaptations.

Intraspecific Competition

Competition among individuals of the same species for limited resources.

Abiotic Factors

Non-living environmental factors that affect living organisms, such as temperature and pH.

Epigenetic Marks

Chemical modifications to DNA that affect gene expression without changing the DNA sequence.

Founder Effect

A type of genetic drift that occurs when a small group establishes a new population, carrying a limited genetic diversity.

Hardy-Weinberg Equilibrium

Condition in which allele frequencies remain constant across generations in the absence of evolutionary influences.

Artificial Selection

The human practice of breeding animals or plants for specific traits, altering allele frequencies in populations.

Directional Selection

Selection that shifts the allele frequency towards one extreme phenotype.

Stabilizing Selection

Selection that favors intermediate phenotypes, reducing variation.

Disruptive Selection

Selection that favors extreme phenotypes over intermediate ones, potentially leading to speciation.

Sexual Selection

The process where traits that enhance mating success become more common, affecting allele frequencies.