Life Science 15: Key Concepts in Genetics, Evolution, and Behavior

Scientific Method

Step-by-step process for testing hypotheses empirically

Hypothesis

A testable, refutable explanation for an observation

Evolution

Change in allele frequencies within a population

Gene

Section of DNA that encodes a specific trait

Allele

Variant form of a gene

Natural Selection

Process by which better-adapted organisms reproduce more successfully

Law of Segregation

Each gamete receives only one allele for each gene

Karyotype

Picture of all chromosomes in a cell

Sex-Linked Traits

Traits determined by genes on sex chromosomes

Inclusive Fitness

Direct + Indirect fitness; explains altruism among kin

Hamilton's Rule

B × r > C; condition for altruistic behavior to evolve

Reciprocal Altruism

Helping others with expectation of future return

Cheater Detection

Essential for maintaining cooperation

Honest Signals

Behaviors that truthfully indicate intentions or quality

STR (Short Tandem Repeat)

Repeating DNA sequence used for genetic identification

DNA Fingerprinting

Using STRs to match genetic samples

Genetic Variation

Differences in DNA sequences among individuals

Homozygous

Two identical alleles for a gene

Heterozygous

Two different alleles for a gene

Heritability

Degree to which traits are passed from parents to offspring