Evolution Flashcards
What is Gene Flow?
The gain or loss of genes through movement between populations
What is Genetic Drift?
The change in a population’s gene frequencies due to chance
Gene Frequency
The ratio the shows what percentage of a population has a certain gene
Change in an environment can affect an organisms what?
fitness
What was the name of Charles Darwin’s ship?
HMS Beagle
What animals did Charles Darwin research and where?
Finches and Tortoises on the Galapagos Islands
What are the five evidences of evolution?
Paleontology (fossils), Biogeography (fossil locations), Embryology (study of Embryos), Molecular Homologies (Bone anatomy) & Molecular Biology (amino acid sequences)
What is an Analogous structure?
Structures (limbs) that have the same function but look different. ex: bat wings & insect’s wings
What is a Homologous structure?
Structures (limbs) that look similar but serve different functions. ex: human arm, dog leg, bird wing, & a whale fin
What is a Vestigial structure?
A feature that was inherited but is not used in the modern world. ex: appendix, wisdom teeth, etc.
How are organisms placed on a Phylogenetic Tree?
Data from evolution evidences show whether an organism shares a common ancestor with others
What is a outgroup on a cladogram?
An outgroup is a species that is the least closely related to the other organisms on the cladogram. ex: if organism a was at the bottom of the graph then it would be the outgroup
What is natural selection?
The process by which individuals which are “more fit” for the environment survive and reproduce
What does natural selection require in order to work?
Natural selection requires genetic variation and an environmental pressure that gives some individuals an advantage
What is an adaptation?
A change that helps an organisms survive and reproduce better. ex: in a population of brown fur bunnies the white fur bunnies survive in the winter months when it snows
What is random mutation?
Changes in the amino acid sequence in an organism which results in the creation of a new genotype variation. ex: in a population of brown fur bunnies a single white fur bunny is born
What is evolutionary fitness?
Any trait that causes an organism to survive and reproduce better
What is sexual selection?
A trait that improves the organisms chance of finding a mate. ex: a peacock with a large & colorful tail is more likely to attract a mate rather than a peacock that has a short & dull tail.
What is the founder effect?
When a new colony is started by few individuals from a large population. ex: within a flock of birds a group of 5 birds decide to migrate somewhere else and start their own flock
What is the bottleneck effect?
When a significant percentage of a population or species is killed or otherwise prevented from reproducing. ex: covid-19 kills 65% of a rural towns population
What is directional selection?
One of the two extreme phenotypes was favored by natural selection
What is stabilizing selection?
Organisms in a population with the extreme traits do not survive and the average (normal) trait thrives. ex: a abnormally small baby has a higher chance of having birth defects; conversely, an abnormally large baby will have a challenge in terms of a safe delivery
What is disruptive selection?
Organisms in a population with the extreme traits survive and the average trait dies out. ex: Female elephant seals are “selected” to be small and males are “selected to be large. Intermediate size is rarely found
What is artificial selection?
Humans directly influence variation within a population. ex: only the largest and juiciest apples are bred while the small and dry ones die off
What is reproductive isolation?
When a organism is no longer able to mate and produce offspring
What is divergent evolution?
When one species splits off into two different species that are unable to mate due to genetic variation between the species.
What is a punctuated equilbrium?
Divergent evolution that occurs quickly after a period of stasis (little evolution).
What is gradualism?
The evolutionary process in which species experience changes in characteristics slowly and incrementally
What is adaptive radiation?
When a species rapidly diversifies due to an abundance of available ecological niches suddenly opening up.
What is niche?
The role an organism plays in an environment.
What are the five parts of natural selection?
Variation, Inheritance, Time, Adaptation, and Selection
What is Non-Random Mating?
The rule that some individuals are more or less likely to mate with individuals of a particular genotype than others
What is Speciation?
The creation of a new species.
What are the 5 Prezygotic Barriers (Reproductive Barriers) ?
Habitat, Temporal, Behavioral, Mechanical, & Gametic
What is the Habitat barrier?
Organisms are unable to reproduce due to having no contact with each other.
What is the Temporal barrier?
Organisms are unable to reproduce due to different mating and breeding seasons.
What is the Behavioral barrier?
Organisms are unable to reproduce due to unrecognizable signals sent for mating.
What is the Mechanical Barrier?
Organisms are unable to reproduce due to being physically incapable of breeding. ex: a snail with a right side shell and a snail with a left side shell.
What is the Gametic Barrier?
Organisms are unable to reproduce due to the incompatibly of the eggs and sperm.
What is Macroevolution?
Evolution that occurs on a large scale. ex: the meteor that killed the dinosaurs
What is Microevolution?
Evolution that occurs on a small scale. ex: pesticide resistance in bugs
What is Phylogeny?
The evolutionary history of a group of organisms, such as a tribe or a racial group. ex: the tree of all life is a schematic model that shows the evolution of organisms both extinct and living.,
What are the 5 mechanisms of evolution?
Mutations, Non-random mating, gene flow, finite population (genetic drift), & natural selection
What is convergent evolution?
When two separate species in different areas evolve to look or behave in a similar manner.
