SBI3U Biology - Evolution Unit Glossary (2024-2025) PDF

SBI 3U 2024-2025 SBI3U Biology - Evolution Unit Glossary Terms Definitions & Explanations Lesson 01 - Introduction to Evolution 23/24 Biological An inherited (heritable) change (variation)...

SBI 3U 2024-2025 SBI3U Biology - Evolution Unit Glossary Terms Definitions & Explanations Lesson 01 - Introduction to Evolution 23/24 Biological An inherited (heritable) change (variation) that happens within a POPULATION, NOT Evolution INDIVIDUALS Microevolution Changes in the allele frequencies within a population over successive generations Macroevolution The progression of biodiversity over a long period of time; involves speciation and extinction and often accumulates from microevolution Mutation a permanent change in the genetic material of an organism; the only source or starting point of new genetic variation Variation differences between individuals, which may be structural, functional, or physiological Adaptation a structure, behaviour, or physiological process that helps an organism survive and reproduce in a particular environment Structural An adaptation in a specific part or feature of the organism’s body (i.e. mimicry, Adaptation camouflage) Physiological Permits an organism to perform a specific function (i.e. Hibernation) Adaptation Behavioural A change in the ways an organism acts (i.e. hunting strategies, migration pattern) Adaptation Selective a genetic advantage that improves an organism’s chance of survival, usually in a Advantage changing environment Fitness the relative contribution an individual makes to the next generation by producing offspring that will survive long enough to reproduce (viable) Mimicry a structural adaptation in which a harmless species resembles a harmful species in coloration or structure Camouflage A structural adaptation in which a species blends into the environment Lesson 02 - Evidence of Evolution Fossil Record Chronological remains and traces of past life that are found in sedimentary rock; it reveals the history of life on Earth and kinds of organisms that were alive in the past 1 SBI 3U 2024-2025 Transitional Fossil a fossil that shows intermediary links between groups of organisms and shares characteristics common to two now separated groups (both ancestral and descendant groups) Ex. Archaeopteryx and Sinusauropteryx Comparative The study of similarities and differences in anatomy between species, one of the Anatomy evidence of evolution Homologous structures that have similar structural elements and origin but may have a different Structure function = Similar structure, different function Ex. Vertebrates share similar arrangement of bones Analogous structures of organisms that do not have a common evolutionary origin (ancestor) Structure but perform similar functions = Similar function, different structures Ex. Butterfly and bat wings Vestigial Structure a structure that is a reduced version of a structure that was functional in the organism’s ancestors, but not functional in the new species due to evolution Biomedical The study of how closely related two organisms are by comparing DNA and proteins Analysis (DNA) Embryology the study of early, pre-birth stages or an organism’s development (to see similar stages of development that are no longer visible in late stages) Biogeography the study of the past and present geographical distribution of species populations Lesson 03 - Mechanisms of Evolution Mutation Change that randomly occurs in the DNA of an INDIVIDUAL that is heritable Neutral Mutation Mutations that occur in non-coding regions of DNA and have no effects Ex. attached earlobe vs. free earlobe Beneficial Mutations that nature selects FOR, allele frequency accumulates over time Mutation Ex. Antibiotic resistance Harmful Mutation Mutations that nature selects AGAINST, allele frequency are very rare Ex. Cystic fibrosis, rare genetic diseases Natural Selection Organisms with advantageous, heritable traits are selected for, survive and reproduce, passing their traits to their offspring Directional A natural selection that favours the phenotypes at one extreme over another, Selection resulting in the distribution curve of phenotypes shifting in the direction of that extreme Disruptive A natural selection that favours the extremes of a range of phenotypes rather than Selection intermediate phenotypes; this type of selection can result in the elimination of 2 SBI 3U 2024-2025 intermediate phenotypes Stabilizing A natural selection that favours intermediate phenotypes and acts against extreme Selection variations (intermediate phenotype keeps high frequency) Random mating A pattern in which any males and females have equal chances of mating Non-random The mating among individuals on the basis of mate selection for a particular mating phenotype or due to inbreeding Inbreeding When closely related individuals breed together, offspring are more likely to have deformities Preferred Selecting a mate based on physical and behavioural traits (phenotypes) Phenotypes Assortative When individuals mate with partners that have similar characteristics/ phenotypes Mating Disassortative When individuals mate with partners that have dissimilar characteristics/ phenotypes Mating Sexual Selection A selection for mating based, in general, on competition between males and choices made by females Certain characteristics are actively sought out by one sex (usually female) Sexual A marked difference between males and females due to sexual selection dimorphism Ex. male peacocks have more attractive colours and females have normal colour Genetic Drift The change in frequencies of alleles due to chance events in a usually small breeding population, some alleles are lost Bottleneck Effect Changes in gene distribution that result from a rapid decrease in population size Ex. natural disasters like drought, tsunami, disease, starvation…. → Decreased genetic diversity Founder Effect A change in a gene pool that occurs when a few individuals start a new isolated population (colonization, migration) → Decreased genetic diversity The net movement of alleles from one population to another due to the migration of Gene Flow individuals (Migration) → Increased genetic diversity Artificial Selection The differential reproduction of genotypes caused by HUMAN INTERVENTION (e.g., breeding dogs, crops). Done to achieve a desired CHARACTERISTIC in the offspring. 3 SBI 3U 2024-2025 Lesson 04 - Speciation Biological Species A species is a population where individuals are able to interbreed and produce viable Concept offspring (lived long enough to reproduce again) Speciation The formation of a new species (macroevolution) Allopatric Speciation in which a population is split into two or more groups by a geographical Speciation barrier; (geographical speciation) With geographical (physical) barriers Sympatric Speciation in which populations within the same geographical areas diverge and Speciation become reproductively (genetically) isolated Without geographical (physical) barriers Lesson 05 - Reproductive Isolating Mechanisms Prezygotic a barrier that either impedes mating between species or prevents fertilization of the Isolating eggs if individuals from different species attempt to mate (pre-fertilization barrier) Mechanism Postzygotic a barrier that prevents hybrid zygotes from developing into viable, fertile individuals Isolating (post-fertilization barrier) Mechanism Ecological Species that occupy separate habitats or different niches of the same habitat do not Isolation mate with each other Temporal Species that have different mating times of day, seasons or different years do not Isolation mate with each other Behavioural Distinct courtship or mating cues for attracting a mate made different species unable Isolation to recognize and mate with each other. Mechanical Highly specialized structural differences in reproductive organs prevents copulation Isolation Gametic Isolation At the molecular level, eggs and sperm can not fertilize, and zygote cannot be formed Zygotic Mortality The fertilized zygote dies before birth (incompatibility of chromosomes) Hybrid Inviability The developing embryo dies before birth or is born alive but cannot survive or live long enough to reproduce again Hybrid Infertility Hybrids develop normally but are sterile (infertile), unable to produce gametes Lesson 06 - Patterns and Speed of Evolution 4 SBI 3U 2024-2025 Lesson 07 - Hardy-Weinberg Equilibrium 5