Natural Selection and Biology Regents Review

Flashcards covering key biological concepts including natural selection, heredity, ecology, and human body homeostasis, formatted as VOCABULARY.

Natural Selection

The process by which genetic variations that improve survival and reproduction become more common in a population over time.

Selecting Agent

An environmental force that favors or disfavors a specific trait in a population.

Speciation

The process where organisms with improved variation become a separate species over time.

Artificial Selection (Selective Breeding)

The process where humans choose desirable traits and breed organisms to pass them on to future generations.

Homologous structures

Anatomical features, such as human arms, bat wings, and whale flippers, that indicate common ancestry.

Vestigial structures

Evolutionary remnants that suggest common descent, such as the whale pelvis or human tailbone.

Phylogeny

The evolutionary history of a group of related organisms, often represented by a phylogenetic tree.

Genetic Variation

The differences in DNA between individuals of the same species.

Mutation

Rare changes in DNA that can introduce new genetic traits and increase variation.

Epigenetics

The study of how behavior and environment can cause heritable changes in gene activity without changing the DNA sequence.

Transgenic organisms

Organisms produced by combining DNA from two different species using genetic engineering.

Transcription

The first step of protein synthesis where DNA is converted into mRNA in the nucleus.

Translation

The second step of protein synthesis where mRNA is converted into amino acids to build a protein at the ribosome.

Gene Expression

The process by which instructions in DNA are used to make a protein, which then gives rise to an organism's traits.

Allele

A specific version of a gene; individuals inherit two alleles per gene, one from each parent.

Meiosis

The process that creates gametes (sex cells) with half the genetic material through crossing over and independent assortment.

Social Affiliation

A strong drive in many animals for interaction with their own species, arising from parent-offspring bonds or peer interactions.

Biomagnification

The process where the concentration of toxic substances increases as it moves up a food web because top predators consume more contaminated prey.

Ecological succession

The process by which one habitat changes into another over time, through stages like pioneer species and climax communities.

Biodiversity

The variety of species in an ecosystem, which contributes to its stability and ability to recover from disturbances.

Energy Flow

The movement of energy through an ecosystem where only approximately $10\%$ is transferred between trophic levels.

Photosynthesis

The process where autotrophs capture light energy to convert $CO_2$ and $H_2O$ into glucose and $O_2$.

Cellular Respiration

The process in the mitochondria where oxygen reacts with glucose to produce ATP, releasing $CO_2$ as a byproduct.

Carrying Capacity

The maximum number of a species that an environment can support due to finite resources.

Niche

The specific role an organism plays in an ecosystem; only one species can occupy a niche at a time without competition.

Mitosis

Cell division that results in two identical daughter cells, used for growth, development, and repair.

Cell Differentiation

The process where stem cells become specialized cell types through specific gene activation.

Homeostasis

The process of maintaining stable internal conditions; failure to maintain this state is defined as disease.

Negative Feedback Loop

A regulatory mechanism that reverses a change to return the body to homeostasis, such as insulin regulating blood sugar.

Enzymes

Proteins that act as biological catalysts by speeding up chemical reactions; their specific structure determines their function.

Selectively Permeable

A property of the cell membrane that only allows some substances to cross based on size or charge.

Active Transport

The movement of substances across a cell membrane that requires the use of energy (ATP).

Stomata

Pores on the underside of leaves that allow $CO_2$, $H_2O$, and $O_2$ to pass through for photosynthesis and waste removal.