Natural Selection
This term defines an organism's ability to survive and produce fertile offspring.
Fitness.
On a phylogenetic tree, this feature represents the most recent common ancestor of two or more lineages.
Node.
This is the maximum population size that a specific environment can sustain over a long period, often denoted as K.
Carrying capacity.
This symbiotic relationship benefits both species involved, such as bees pollinating flowers.
Mutualism.
Vestigial structures, such as the human appendix or whale hip bones, provide evidence for this, indicating a structure had a function in an ancestor but not in the modern species.
Evolution/common ancestry.
This type of speciation occurs when a population is divided by a geographic barrier, such as a canyon or river.
Allopatric speciation.
This type of population growth, characterized by a J-shaped curve, occurs when resources are unlimited.
Exponential growth.
This type of ecological succession occurs in an area where no soil exists, such as on a new volcanic island.
Primary succession.
This mechanism of evolution occurs when a small group becomes isolated, leading to an allele frequency that is different from the original, larger population.
The Founder effect.
These are structural similarities, like the wings of a bird and a butterfly, that result from similar environmental pressures rather than shared ancestry.
Analogous structures.
This term describes the role and position a species has in its environment, including how it meets its needs for food and shelter.
Niche.
When two species compete for the same limiting resource, one will eventually be eliminated, a principle known as this.
Competitive exclusion.
This type of evidence, often using BLAST, compares amino acid sequences in proteins like cytochrome c to determine how closely related species are.
Molecular homology.
This prezygotic barrier occurs when two species mate at different times of the year.
Temporal isolation.
As energy flows through trophic levels, only about this percentage is transferred to the next level.
10%.
This behavioral response is a daily, 24-hour cycle of activity, such as sleeping at night and being awake during the day.
Circadian rhythm.
Antibiotic resistance in bacteria is a direct example of this type of selection, which favors one extreme phenotype over another in a changing environment.
Directional Selection.
This hypothesis suggests that RNA was the first genetic material because it can store information and catalyze reactions.
RNA-world hypothesis.
This type of species has a disproportionately large effect on its environment relative to its abundance, such as sea otters.
Keystone species.
This occurs when a change in one trophic level causes a series of effects up or down the food chain, such as wolves affecting vegetation growth.
Trophic cascade.