| Term | Definition |
|---|---|
| abiotic environment | The non-living physical and chemical components of an ecosystem, such as temperature, light, and water. |
| biotic environment | The living components of an ecosystem, including organisms and their interactions. |
| competition for limited resources | The struggle among organisms for access to finite environmental resources, which results in differential survival and reproduction. |
| differential survival | The unequal survival rates of individuals in a population based on differences in their traits or phenotypes. |
| evolution | The process of change in living organisms over time, involving genetic modifications and adaptation to environments. |
| evolutionary fitness | The measure of an organism's reproductive success, determined by how many viable offspring it produces. |
| favorable phenotype | A set of observable traits that increases an organism's likelihood of survival and reproduction in its environment. |
| genetic variation | Differences in DNA sequences and alleles that exist within a population. |
| natural selection | A major mechanism of evolution in which individuals with more favorable phenotypes are more likely to survive and reproduce, passing advantageous traits to subsequent generations. |
| offspring | The individual organisms produced by reproduction from parent organisms. |
| phenotype | The observable physical and biochemical characteristics of an organism, determined by both genetic and environmental factors. |
| population | A group of organisms of the same species living in the same geographic area. |
| reproductive success | An organism's ability to produce viable offspring that survive and reproduce. |
| traits | Specific characteristics or features of an organism that can be inherited and passed to offspring. |
| Term | Definition |
|---|---|
| adaptive radiation | The rapid evolution and diversification of a single ancestral species into multiple species that occupy different habitats or ecological niches. |
| allopatric speciation | Speciation that occurs in populations that are geographically isolated from one another. |
| biological species concept | A definition of species based on the ability of organisms to interbreed and produce viable, fertile offspring. |
| convergent evolution | Evolution in which different populations or species develop similar phenotypic adaptations in response to similar selective pressures. |
| divergent evolution | Evolution in which populations or species become increasingly different from each other, often due to adaptation to different habitats. |
| fertile | Capable of producing offspring; able to reproduce. |
| gene flow | The transfer of alleles into or out of a population as a result of migration. |
| geographic isolation | The physical separation of populations by geographic barriers that prevents gene flow between them. |
| gradualism | A pattern of evolution in which evolutionary change occurs slowly and continuously over hundreds of thousands or millions of years. |
| interbreeding | The process of mating and reproduction between members of different populations or groups. |
| phenotypic diversification | An increase in the variety of observable physical traits within or among populations. |
| post-zygotic mechanisms | Reproductive barriers that reduce the viability or fertility of hybrid offspring after zygote formation. |
| pre-zygotic mechanisms | Reproductive barriers that prevent fertilization from occurring by preventing gamete fusion before zygote formation. |
| punctuated equilibrium | A pattern of evolution in which rapid evolutionary change occurs after long periods of stasis, or little change. |
| reproductive isolation | The inability of different populations or species to interbreed and produce viable, fertile offspring. |
| reproductively isolated | A condition in which two populations are unable to interbreed and exchange genetic information, preventing gene flow between them. |
| selective pressure | Environmental factors that influence which traits are advantageous for survival and reproduction in a population. |
| speciation | The evolutionary process by which new species arise from existing species through reproductive isolation and genetic divergence. |
| stasis | A period of little or no evolutionary change in a population or species. |
| sympatric speciation | Speciation that occurs within populations that share the same geographic area or have geographic overlap. |
| viable | Capable of living, developing, or functioning successfully. |
| Term | Definition |
|---|---|
| adaptive alleles | Alleles that increase an organism's fitness and ability to survive and reproduce in a particular environment. |
| allele | Different versions of a gene that can exist at the same location on a chromosome. |
| deleterious alleles | Alleles that decrease an organism's fitness and ability to survive and reproduce in a particular environment. |
| environmental pressure | External environmental conditions or stressors that affect the survival and reproduction of organisms in a population. |
| extinction | The permanent disappearance of a species from Earth, occurring when all individuals of that species die. |
| genetic diversity | The variety of different alleles and genes present within a population or species. |
| population dynamics | Changes in population size and structure over time, influenced by interactions with other populations and environmental factors. |
| resilience | The ability of an ecosystem to withstand and recover from environmental changes or disturbances. |
| selective pressure | Environmental factors that influence which traits are advantageous for survival and reproduction in a population. |
| Term | Definition |
|---|---|
| base-pairing | The complementary bonding between nitrogenous bases in nucleic acids that enables accurate replication and information transfer. |
| fossil evidence | Physical remains or traces of ancient organisms preserved in rock that provide direct evidence of past life on Earth. |
| genetic continuity | The unbroken transmission of genetic information from one generation to the next through accurate replication of genetic material. |
| genetic material | Molecules that store and transmit hereditary information in living organisms. |
| geological evidence | Physical and chemical evidence from Earth's rocks, minerals, and geological structures that provides information about Earth's history and the conditions of early life. |
| RNA replication | The process by which RNA molecules make copies of themselves through base-pairing interactions. |
| RNA world hypothesis | A scientific model proposing that RNA served as the earliest genetic material and catalyst in primitive life forms before the evolution of DNA and proteins. |
| scientific evidence | Data and observations from empirical research that support or refute scientific claims, including evidence for evolution. |
| Term | Definition |
|---|---|
| fitness | An organism's ability to survive and reproduce successfully, passing its genes to the next generation. |
| molecules | Chemical compounds made up of atoms that perform specific functions within cells. |
| natural selection | A major mechanism of evolution in which individuals with more favorable phenotypes are more likely to survive and reproduce, passing advantageous traits to subsequent generations. |
| phenotypic variation | Differences in observable characteristics or traits among individuals in a population. |
| population | A group of organisms of the same species living in the same geographic area. |
| selective pressure | Environmental factors that influence which traits are advantageous for survival and reproduction in a population. |
| variation | Differences in traits among individuals within a population due to genetic and environmental factors. |
| Term | Definition |
|---|---|
| artificial selection | The process by which humans deliberately choose organisms with specific traits to breed together, thereby changing the frequency of traits in a population over time. |
| diversity | The variety of different traits, alleles, and genetic variation present within a population. |
| variation | Differences in traits among individuals within a population due to genetic and environmental factors. |
| Term | Definition |
|---|---|
| allele frequencies | The proportion or percentage of a specific allele in a population's gene pool. |
| bottleneck effect | A type of genetic drift that occurs when a population is drastically reduced in size, causing random changes in allele frequencies. |
| evolution | The process of change in living organisms over time, involving genetic modifications and adaptation to environments. |
| founder effect | A type of genetic drift that occurs when a small group of individuals establishes a new population, resulting in allele frequencies that differ from the original population. |
| gene flow | The transfer of alleles into or out of a population as a result of migration. |
| genetic drift | Random changes in allele frequencies in a population due to nonselective processes, particularly in small populations. |
| genetic makeup | The complete set of alleles and genes present in a population that determine the heritable traits of its members. |
| genetic variation | Differences in DNA sequences and alleles that exist within a population. |
| migration | The movement of individuals (and their alleles) into or out of a population; must be absent for Hardy-Weinberg Equilibrium. |
| mutation | An alteration in a DNA sequence that can cause changes in the type or amount of protein produced and the resulting phenotype. |
| mutations | Random changes in DNA sequences that create new genetic variations in populations. |
| random occurrences | Unpredictable events that affect allele frequencies in populations independent of natural selection. |
| random processes | Unpredictable events that cause changes in allele frequencies in populations, independent of natural selection. |
| Term | Definition |
|---|---|
| allele frequencies | The proportion or percentage of a specific allele in a population's gene pool. |
| genotype frequencies | The proportion or percentage of each genotype combination in a population. |
| Hardy-Weinberg Equilibrium | A model describing a non-evolving population where allele and genotype frequencies remain constant across generations. |
| large population size | A condition for Hardy-Weinberg Equilibrium where a population is large enough to prevent random changes in allele frequencies due to chance events. |
| migration | The movement of individuals (and their alleles) into or out of a population; must be absent for Hardy-Weinberg Equilibrium. |
| mutations | Random changes in DNA sequences that create new genetic variations in populations. |
| natural selection | A major mechanism of evolution in which individuals with more favorable phenotypes are more likely to survive and reproduce, passing advantageous traits to subsequent generations. |
| non-evolving population | A population in which allele frequencies do not change over time because evolutionary forces are absent. |
| null hypothesis | A baseline model used for comparison; in this context, Hardy-Weinberg Equilibrium serves as a reference point to detect when populations are evolving. |
| random mating | A condition where individuals in a population mate without preference for specific genotypes; required for Hardy-Weinberg Equilibrium. |
| Term | Definition |
|---|---|
| biochemical data | Information about molecular and chemical composition of organisms, such as DNA and proteins, that provides evidence for evolution. |
| carbon-14 dating | A radiometric dating method that measures the decay of the carbon-14 isotope to determine the age of fossils. |
| common ancestry | The concept that all organisms share a common evolutionary origin and are related through descent from earlier ancestral species. |
| DNA nucleotide sequences | The specific order of nucleotides in DNA that can be compared between organisms to determine evolutionary relationships. |
| evolution | The process of change in living organisms over time, involving genetic modifications and adaptation to environments. |
| extant organisms | Living organisms that exist in the present day. |
| extinct organisms | Organisms that no longer exist and are known only through fossil records. |
| fossil | Preserved remains or traces of organisms from past geological time periods. |
| geographical data | Information about the distribution and location of organisms across different regions that provides evidence for evolution. |
| geological data | Information about rock layers and Earth's history used to date fossils and understand evolutionary timescales. |
| isotope decay | The process by which unstable isotopes break down over time at a predictable rate, used to determine the age of rocks and fossils. |
| mathematical data | Quantitative analysis and statistical information used to model and support evolutionary patterns and relationships. |
| molecular evidence | Data from DNA nucleotide sequences and protein amino acid sequences that demonstrates evolutionary relationships between organisms. |
| morphological homologies | Structural similarities in different organisms that indicate common ancestry and evolutionary relationships. |
| morphological traits | Physical characteristics or structures of organisms used to determine evolutionary relationships. |
| physical data | Observable structural and anatomical information about organisms that provides evidence for evolution. |
| protein amino acid sequences | The specific order of amino acids in proteins that can be compared between organisms to provide evidence for evolution. |
| scientific evidence | Data and observations from empirical research that support or refute scientific claims, including evidence for evolution. |
| vestigial structures | Reduced or non-functional body parts that are remnants from ancestral organisms and provide evidence of common ancestry. |
| Term | Definition |
|---|---|
| common ancestry | The concept that all organisms share a common evolutionary origin and are related through descent from earlier ancestral species. |
| eukaryotes | Organisms whose cells contain a membrane-bound nucleus and other membrane-bound organelles. |
| functional evidence | Observable processes and biochemical functions of cells and organisms that indicate evolutionary relationships and common ancestry. |
| intron | A non-coding segment of a eukaryotic gene that is removed from the mRNA transcript during RNA processing. |
| linear chromosomes | Chromosomes with defined endpoints found in eukaryotic cell nuclei, as opposed to the circular chromosomes found in prokaryotes. |
| membrane-bound organelle | Specialized structures within eukaryotic cells enclosed by a membrane that perform specific cellular functions. |
| structural evidence | Physical characteristics of cells and organisms that indicate evolutionary relationships and common ancestry. |
| Term | Definition |
|---|---|
| antibiotic resistance | The ability of bacteria and other microorganisms to survive and reproduce in the presence of antibiotics that would normally kill them. |
| chemotherapy drug resistance | The ability of cancer cells to survive and proliferate despite exposure to chemotherapy drugs. |
| emergent diseases | Infectious diseases that have recently appeared in a population or are rapidly increasing in incidence or geographic range. |
| evolution | The process of change in living organisms over time, involving genetic modifications and adaptation to environments. |
| fossil record | The preserved remains and traces of organisms from past geological periods that document changes in life forms over time. |
| genomic changes | Alterations in the DNA sequence of an organism's genome that accumulate over time. |
| herbicide resistance | The ability of plants to survive and grow in the presence of herbicides designed to kill them. |
| pathogens | Organisms or agents, such as bacteria, viruses, or parasites, that cause disease in host organisms. |
| pesticide resistance | The ability of organisms, particularly insects and plants, to survive exposure to pesticides that would normally be lethal. |
| Term | Definition |
|---|---|
| cladogram | A branching diagram that shows hypothetical evolutionary relationships among lineages without indicating time scale or the amount of evolutionary change between groups. |
| DNA sequence similarities | Resemblances in the order of nucleotides in DNA between different organisms, used to infer evolutionary relationships. |
| evolutionary relationship | A connection between organisms based on their shared ancestry and descent from a common ancestor. |
| molecular clock | A method that uses the rate of molecular change (mutations) to estimate the time since organisms diverged from a common ancestor. |
| molecular evidence | Data from DNA nucleotide sequences and protein amino acid sequences that demonstrates evolutionary relationships between organisms. |
| morphological similarities | Structural and physical resemblances between organisms based on body form and anatomy. |
| morphological traits | Physical characteristics or structures of organisms used to determine evolutionary relationships. |
| most recent common ancestor | The most immediate ancestral species or population from which two or more groups diverged during evolution. |
| nodes | Points on a phylogenetic tree or cladogram that represent the most recent common ancestor of two or more groups or lineages. |
| out-group | The lineage in a phylogenetic tree or cladogram that is least closely related to the remainder of the organisms being compared. |
| phylogenetic tree | A diagram that shows hypothetical evolutionary relationships among lineages, including time scale and the amount of evolutionary change over time. |
| protein sequence similarities | Resemblances in the order of amino acids in proteins between different organisms, used to infer evolutionary relationships. |
| shared derived characters | Traits that are present in multiple lineages and were inherited from a common ancestor, indicating common ancestry and used to construct phylogenetic trees and cladograms. |
| speciation | The evolutionary process by which new species arise from existing species through reproductive isolation and genetic divergence. |