Evolution, Ecology, and Behavior Study Set

Vocabulary terms and definitions covering Evolution, Animal Behavior, and Ecology concepts based on biology lecture notes.

Evolution

Changes in a population’s traits over time that enhance survival, reproduction, and adaptation to the environment.

Microevolution

Minor evolutionary changes resulting from small-scale shifts in allele frequencies, such as bacteria evolving antibiotic resistance.

Macroevolution

Major evolutionary changes resulting from sudden, large-scale events or the accumulation of small-scale adaptations, such as birds evolving from dinosaurs.

Phylogeny

Evolutionary relationships between organisms.

Monophyletic group

A common ancestor and all of its descendants; also known as a clade.

Oparin-Haldane Hypothesis

The theory that Earth’s early atmosphere was reducing and that inorganic compounds formed into organic compounds using energy from lightning and UV radiation.

Miller-Urey Experiment

An experiment that confirmed the Oparin-Haldane hypothesis by simulating early Earth conditions and successfully forming organic molecules like amino acids.

RNA World Hypothesis

The hypothesis that RNA was the first genetic material to evolve because it can both store information and catalyze reactions.

Endosymbiotic Theory

The theory that some eukaryotic organelles, specifically mitochondria and chloroplasts, arose from prokaryotic cells.

Homologous structures

Anatomical features that originate from a shared common ancestor, showing similarity in structure but not necessarily in function.

Analogous structures

Anatomical features with similar functions but different underlying structures that evolved as adaptations to similar environments without common ancestry.

Vestigial structures

Modern structures that have lost their original function, such as the human appendix.

Catastrophism

The theory proposed by Georges Cuvier that Earth's history was shaped by violent, large-scale catastrophes leading to significant changes over short time scales.

Uniformitarianism

The geological theory that Earth’s history was shaped by gradual processes over long periods of time, such as erosion.

Darwin-Wallace Theory

The theory of natural selection and survival of the fittest, focusing on an organism's ability to survive and reproduce based on advantageous traits.

Stabilizing selection

Natural selection that favors intermediate phenotypes while extreme phenotypes are unfavored, narrowing the population distribution toward the mean.

Directional selection

Natural selection that favors one extreme phenotype over the other extreme or intermediate phenotypes, shifting the distribution toward that extreme.

Disruptive selection

Natural selection that favors extreme phenotypes while intermediate phenotypes are unfavored, causing the distribution to diverge from the mean.

Genetic drift

Random increase or decrease in allele frequency due to chance events, with a larger effect on small populations.

Bottleneck effect

A mechanism of genetic drift where a population is reduced in size due to a catastrophic event, leaving a surviving population with altered allele frequencies.

Hardy-Weinberg Equilibrium

A hypothetical state of genetic equilibrium where allele frequencies do not change and evolution does not occur, defined by the equations $p^2 + 2pq + q^2 = 1$ and $p + q = 1$.

Allopatric speciation

Speciation that occurs when populations are separated by a physical or geographic barrier.

Sympatric speciation

Speciation that occurs without a physical barrier, developed through reproductive isolation mechanisms within the same geographic area.

Adaptive radiation

The rapid evolution of many species from a single ancestor when a species enters a new environment with many open niches.

Mullerian mimicry

A defense mechanism where two or more species resemble each other in appearance and both share the same dangerous defense mechanism.

Batesian mimicry

A defense mechanism where a non-dangerous species evolves to resemble a dangerous species to avoid predation.

Innate behavior

Instinctive, biologically inherited behaviors that an animal is born with and are not learned.

Fixed action patterns

Complex innate behaviors that follow a predictable sequence of actions in response to a sign stimulus and are always completed once initiated.

Classical conditioning

A form of associative learning where a biological response becomes associated with a neutral stimulus, converting it into a conditioned stimulus.

Operant conditioning

Trial and error learning where an animal modifies behavior in response to reinforcements (favorable outcomes) or punishments (unfavorable outcomes).

Pheromones

Chemical signals released by animals to trigger responses in members of the same species, such as attracting mates or marking territory.

Altruistic behavior

A social behavior that benefits other animals while putting the individual performing the action at a disadvantage.

Inclusive fitness

The combination of direct fitness (an individual’s reproductive success) and indirect fitness (the reproductive success of related individuals).

Semelparity

A reproductive strategy where an animal reproduces only once in its life, producing many offspring in a single event.

Iteroparity

A reproductive strategy where an animal reproduces throughout its life, producing fewer offspring per event.

Fundamental niche

The full range of environments that could potentially support an organism’s survival.

Realized niche

The actual range of environments an organism occupies, typically smaller than the fundamental niche due to limiting factors like competition.

Carrying capacity

The maximum population size that a habitat can sustain due to limited resources.

Keystone species

A species that has a major impact on ecosystem balance, such that its removal can cause the ecosystem to collapse.

Secondary succession

Ecological succession occurring in areas that previously supported life before it was destroyed by a catastrophe, which is faster than primary succession due to existing soil.

Trophic efficiency

The amount of energy transferred from one trophic level to the next, which is typically only around $10\%$..

Biological magnification

The process where human pollutants like pesticides become more concentrated at higher trophic levels in an ecosystem.

Rain shadows

Dry areas on the leeward side of a mountain produced when air cools and drops precipitation on the windward side and kemudian warms up as it travels down the other side.