Evir. Science Exam #3 Flashcards
Evolution
Changing in gene frequency within a population from 1 generation to the next
Genetic Diversity
Populations that contain genetically different individuals, which is needed for populations to evolve
Genetic Mutation
changes in DNA structure
Genetic Recombination
combination of traits arising from both parents
Natural Selection must have
genetic variation and selective pressure
Higher genetic variation means
the better chance individuals can withstand or thrive changing environmental conditions
What are the 2 main sources for genetic diversity?
Genetic mutation and genetic recombination
Natural selection must have both
genetic variation and selective pressure
Adaptations
traits favored by the environment
What is true about the evolutionary processes?
Evolution acts on existing genetic variation
Steps in Natural Selection
- Individuals with the best adaptations survive and reproduce
- The population contains more of the better-adapted individuals
- Changes in how common certain genes are
- The population has experienced evolution
Individuals are _____ for, populations ____
selected, evolve
Directional Selection
continually favors a particular extreme of the trait
Stabilizing Selection
favors the norm and selects against extremes
Disruptive Selection
favors the extremes but selects against the intermediate forms
Coevolution
when 2 species provide pressure determining which of the other’s trait is favored by natural selection
Genetic Drift
Pure chance and random mating that increases or decreases the frequency of a trait
Bottleneck Effect
Part of the population dies suddenly, leaving the survivors left to produce a new generation
Founder Effect
Small group contains only some of the original variants and becomes isolated
What is the change in gene frequency within a population called?
Evolution
Evolution can occur when random mating eliminates some genes from the population. This is called
genetic drift
Artificial Selection
selecting individuals to breed and produce a population with desired traits
Evolutionary fitness
measures the relative ability of an individual to produce viable, fertile offspring, relative to other individuals in the population
Which group of organisms have we identified the most species?
Insects
Biodiversity
the variety of life on Early, includes genetics species, and ecological diversity
What regions have the highest biodiversity?
Tropical
Nature is approximately worth
$125,000,000,000,000
Genetic Biodiversity
heritable variation among individuals of a single population