Evolutionary Biology Overview

Changes in a population's traits over generations, passed down through genes.

All life forms share a single ancestor.

Organisms better suited to their environment are more likely to survive and reproduce.

Similarities in body structures, even if functions differ.

Unrelated species develop similar traits due to similar environments.

A reduced or nonfunctional structure suggesting a shared ancestor.

A system that organizes organisms into groups based on shared characteristics implying evolutionary relationships.

Similarities in early stages of development can show evolutionary relationships.

A group of individuals that can interbreed and produce fertile offspring. They cannot reproduce fertile offspring with members of other species.

Prevention of gene flow between species, meaning they can't interbreed and mix their genes. There are pre-fertilization and post-fertilization barriers preventing this mixing.

A type of reproductive isolation where species live in different places and thus cannot interact for mating.

A type of reproductive isolation where species have different mating rituals, preventing interbreeding.

The process of one or more new species evolving from an ancestral form. It involves three steps: 1. Isolation, 2. Divergence, and 3. Reproductive isolation.

The close similarity in DNA sequences between various organisms suggests a shared ancestry.

Organisms acquire changes during their lifetime, which are then passed down to their offspring, driving evolution.

Darwinian evolution focuses on inheritable variations, while Lamarckian evolution emphasizes acquired traits.

Natural selection requires variations within a population, heritable traits, overproduction, and non-random survival and reproduction.

Fitness refers to an individual's relative survival and reproduction compared to others in the population.

An adaptation is a trait that increases an individual's fitness in its environment, making it more likely to survive and reproduce.

Natural selection leads to changes in the traits of a population over generations, favoring beneficial variations and eliminating unfavorable ones.

Artificial selection is a human-driven process of selectively breeding organisms with desired traits. It mirrors the mechanism of natural selection, but with human intervention.

Natural selection can only work with the existing genetic variations within a population; it cannot create new traits on demand.

Natural selection favors traits that increase an individual's fitness in a particular environment, gradually leading to adaptations that make a species better suited to its surroundings.

A type of genetic drift where a small group of individuals establishes a new population, leading to a different allele frequency compared to the original population.

A type of genetic drift where a large population experiences a drastic reduction in size, usually due to a disaster. The surviving individuals have a different allele frequency than the original population.

In small populations, random fluctuations in allele frequencies are more likely to occur due to chance events. This can lead to the loss or fixation of alleles.

A type of natural selection where individuals with certain traits are more likely to find mates and reproduce, leading to the increased frequency of those traits in the next generation.

A mating pattern where individuals prefer to mate with others who have similar traits, like height or social characteristics. This can lead to increased variation between groups.

Populations separated by geographic barriers like mountains or rivers, preventing gene flow.

Populations living near each other but with reproductive isolation due to differences in mating behavior, habitat preferences, or other factors.

A process of chromosome duplication that can lead to instant speciation by making infertile plant hybrids fertile.

The rapid formation of a new species due to polyploidy, isolating the new organism from its parents.

Evolutionary change that occurs gradually over long periods, with small changes accumulating over time.

Evolutionary change that occurs in bursts of rapid change followed by periods of stability.

Defines species based on shared ancestry and independent evolutionary lineages, acknowledging that organisms can interbreed.

Random changes in allele frequencies within a population, especially significant in small populations.

A type of natural selection where extreme traits are favored over intermediate traits, leading to two or more distinct variants within a population.

The ability of bacteria to survive and multiply in the presence of antibiotics, often caused by mutations that allow them to resist the effects of the drug.

Continuing antibiotic treatment for a longer period, even after symptoms subside, to reduce the likelihood of resistant bacteria developing.

Using multiple antibiotics simultaneously to target bacteria from different angles, making it harder for them to develop resistance.

The variety of life on Earth, encompassing the different species, ecosystems, and genetic diversity within species.

Using scientific methods to estimate the number of species that are yet to be discovered, based on known patterns and extrapolated data.

A representation of the evolutionary relationships among all living organisms, showing their shared ancestry and branching patterns over time.

Analyzing DNA sequences of different organisms to determine their evolutionary relationships, based on the principle that closely related species share more similar DNA.

Large, fundamental classifications of life based on fundamental cellular structures, reflecting ancient divergences and biological relationships.

Organisms that lack a nucleus and other membrane-bound organelles within their cells, including bacteria and archaea.

Photosynthetic bacteria that produce oxygen and fix nitrogen, playing a crucial role in shaping Earth's early atmosphere.

The theory that proposes that mitochondria and chloroplasts, organelles found in eukaryotic cells, evolved from bacteria that were engulfed by early eukaryotic cells.

A diverse kingdom of eukaryotic microorganisms that includes algae, slime molds, and protozoa, with varying modes of nutrition and lifestyles.

The kingdom of multicellular eukaryotes that includes all animals, characterized by their ability to move and their heterotrophic mode of nutrition.

The kingdom of heterotrophic eukaryotes that includes mushrooms, molds, and yeasts, characterized by their ability to absorb nutrients from dead or decaying matter.