Evolution Booklet 24_25 PDF

Evolutio 1 Introduction to the Theory of Evolution (Slideshow 1) Watch the following video and answer the questions: 1. Define hypothesis. Hypothesis # theory...

Evolutio 1 Introduction to the Theory of Evolution (Slideshow 1) Watch the following video and answer the questions: 1. Define hypothesis. Hypothesis # theory · educated guess based limited info · Proposed explanations on · basis of further research > - Can be tested 2. Define scientific theory and provide an example. Explains WHY it happens (reasoning > - · Supported by scientific evidence fortified by facts and repeatedly tested. , · revised with improved evidence and technological advancements. Ex Cell atomic theory of ·. theory , , theory gravity , evolution , general relativity 3. Define law and provide an example. > - Describes what is HAPPENING (phenomenon · Can be summarized mathematically · Ex Newton's2nd Law of. motion , Mendel's law of dominance...... 4. Why do some people say, “it’s just a theory”? hunch. Theory tends to be used more casually in everyday life to mean an opinion guess , or Mutations, Variations and Adaptations difference Variation: The _________________________ between individuals within a species The number of possible combinations of alleles that offspring can inherit from their parents results in genetic variation among individuals within a population. > - Diversity Mutations are the starting point of genetic variation in populations DNA of an organism. Mutations are changes in the _________ o allele Provide new ___________________ in a population > - leads to microevolution o The only source of ____________ new genetic variation within a species. If a mutation occurs in a somatic (body) cell, the mutation disappears from the population when the organism dies. If the mutation alters the DNA in a gamete, the mutation may be passed on to succeeding generations. These inherited (heritable) mutations are ____________________________. Biological Evolution An inherited (heritable) change (variation) that happens within a ______________________ (NOT Population individuals ____________________) allele Change in the ____________________________________ frequencies within a population From Variation to Adaptation Variations accumulate when they become adaptations. Adaptation: is a structure, behaviour, or a physiological process that Survive helps an organism _________________ reproduce and __________________ in a particular environment Adaptations make organisms well suited to their habitat. Evolutionary adaptations are NOT a response to the (spontaneous) environment, but a __________________________ of the environment Consequence (forced to evolve) 3 Natural selection 2 Another word for reproductive success is fitness Fitness: often described as the relative contribution(number) an organism makes to the next generation by producing viable offspring that are ________________ (will survive long enough to reproduce) m An organism with many viable offspring = ______________ fitness An organism with few or no viable offspring = _____________ fitness creates Mutations - > Variation cumulates selective advantage Adaptation Connection between mutation, variation and adaptation: An adaptation develops when a specific_____________ variation (random, heritable mutation in DNA) provides a selective advantage __________________________________ (genetic advantage that improves an organism’s chances of survival and reproduction) accumulate in a population advantageous variation This _______________________________________ will gradually ______________ (microevolution Change in the allele frequency within a population = _____________________ 3 Types of Adaptations: Structural Physiological Behavioural Specific part or feature of the Permits an organism to perform a Ways an organism acts organism’s body specific function Fluffy feathers of an oul Ex) allow them to make their Ex) Hibernation allows flight silent to catch prey ; Ex) Hunting strategies squirrels to survive good vision for owl or an harsh Migration pattern winter Mimicry: Harmless species physically resemble a harmful species Camouflage: blends into the environment. Types of Evolution Microevolution Macroevolution - within Changes in allele frequencies ________________ - long The progression of biodiversity over a _________ a population ______________________ generations over successive - period of time Descent of many species from a ___________ common - Allele frequencies = number of copies of an ancestor ___________________ allele compared to the total number of alleles in - Accumulation of many instances of a population microevolution - speciation Involves __________________ (new species) and extinction Practice: 1. Choose two organisms and research adaptations they have in order to survive in their environment Apple snails Organism:_________________________ Snowshoe hares Organism:_________________________ Developed lungl gills that allow them to Fur color changes to white to help them survive in environments blend into snow Ccamouflage) to protect them oxygen poor such as swamps or shallow water. from predators (wolves , foxes) 2. True or false? “Mutations are caused by selective pressure in the environment.” Justify your answer. False Mutations are random changes in DNA that creates new allele. and points of variation. Variation then develops into are the starting selective pressures evolution. adaptions due to , eventually leading to 3  Evidence For Evolution (Slideshow 2) The place of humans in the history of life: If 500 sheets of paper represents the existence of time, 1/5 of one sheet represent the age of humans, and recent humans would represent only a sliver Humans have only been around for a very short time and so a lot of our fossil evidence came from organisms that existed way before we did Evidence Type Diagram How Does this Support Evolution? modern form youngest Chronological collection of life’s remains in FOSSILS Sedimentary ________________________________ rock layers, hard tar pits, volcanic ash, peat bogs, or amber. Shows the history of life by showing the kinds of species that * Transitional species were alive in the past > sedimentary rockfounda A oldest The Importance of the Burgess Shale in B.C.: Age: from the Cambrian period (~508 million years ago) Shortly after an astonishing burst of biodiversity occurred in the ancient____________. oceans > usually gets - decomposed Preservation of ___________________________ soft-bodied animals ○ Mostly arthropods (phylum including - insects/crustaceans) ○ Not only the hard parts – bones, shells, teeth – but also the muscles, gills, digestive systems Opportunity to observe the way the creatures lived and interacted Fossil Evidence Fossils found in ________________ layers of rock are young alivetoday a much more similar to species __________________ than fossils found in older layers of rock transition Shows the __________________ from species to species 99% species are extinct! _________ = Transitional Not all organisms appear → gaps in fossil records Fossils Fossils of transitional species, when found, provide a lot of information for filling in these precious gaps in-between species Transitional species: A species that has characteristics that are shared by more than one major group of organisms Has traits of an ____________________l ancestral group as well as descendant derived __________________ group links Transition Fossils show intermediary ___________ between groups of organisms are sometimes found later 4  # Are2 clades of dinosaurs 122-124 million ers Ex) Sinosauropteryx > - First and most primitive of dinosaur -tenus with is found fossilized impressions of 150 million feathers. limitive yes Ex) Archaeopteryx First "bird"-bird-like dinosaur > - Birds. Dinosaurs ↳ had feathers and (bird-like) but also had glided , teeth, daws itswings on bony + /reptile-like a tail ↳ allow us to find Vestigial features. Transitional Species ↳ Earliest member of Ares (birds) developed from small-eating dinos Similar structure 3 HomologousThe study of similarities and differences in anatomy between. COMPARATIVE different function species. ANATOMY Homologous → Anatomical structures found in different species that have similar structure and were delived from a common ancestor ↳ Could have different functions 3 Ex Vertebrates all have same basic. arrangement of bones but have different functions Flipper of porpoise wing of bat of ↳ , a , leg horse or frog , human arm Analogous → · Structures that have similar functions but DO NOT share a common. ancestor · Anatomically different but perform a similar function. endred in different species because · Probably share similar ecological units similar function Analogous different structure b Evolved in a similar environment Ex. Bat wings & butterfly wings Vestigial → Homologous characteristics of organisms that have lost all or most of their original function in a species through evolution In humans : tailbones , ear muscles wisdom , teeth Ex) of flightless birds Wings Pelvis and femur in whales Scientists can determine how closely related two organisms are by comparing DNA and proteins. BIOCHEMICAL ANALYSIS · Used the method of DNA barcoding (DNA) Ex) Dogs are related to bears whales and dolphins related to hooved EX) are animals 5  pre-birth The study of early, __________________ stages of an organism’s > in late differentiate stages - development. those that EMBRYOLOGY Embryos of closely related organism often have similar stages in development distribution The study of the __________________________ of organisms BIOGEOGRAPHY and ecosystems in space and through geological time. past + present Ex) Fossil distribution of these 4 species (left graph) matches the of Earth's land masses arrangements at the time species were alive. Supercontinent Ex) Fossils of the same species can be found on the coastline of neighboring continents - islands Ex) Animals found on ___________________ often closely continent related to those found in the nearest ___________________ ↳ Continent animals migrated to islands and over time adapted to island conditions. Ex) Geographically close environments are more likely to be populated by related species, than are locations that are geographically separate, but environmentally similar ↳ Desert/forest in South America are more similar than a desert in SA. and a desert in Australia. Practice: Let’s take a look at the fossil of an odd and old organism, Archaeopteryx. Go to the following url: https://www.livescience.com/24745-archaeopteryx.html Key features seen: · About the size of a common raven (1 8. to 2 2. lbs , 50 cm) · broad hings/rounded ends · body plumage · tail long for its body length. Carricones diet We classify the Archaeopteryx as a transitional species because: It has a blend of alian and reptilian features , showing evolution from dinosaurs into birds List characteristics of Archaeopteryx that are reptile like: · Jaws with sharp teeth · Hyperextensible second toes known as · 3 fingers with claws "killing daws" Did not spent time in trees Dess gliding) A long bony tail · · , List characteristics of Archaeopteryx that are birdlike: · well-developed asymmetrical flight feathers · aerodynamic ability (to fly over short distances) 6  Mechanisms for Evolution (Slideshow 4) If evolution is change over time, what causes the change? There are 5 mechanisms that change allele frequencies in populations therefore causing microevolution! 1 Mutations > - Neutral , Beneficial , harmful 2 Natural Selection Preferred Phenotypes Sexual Selection 3 Non-random mating a Inbreeding , , 4 Genetic Drift > - Bottleneck effect, founder effect 5 Gene Flow (Migration) Mutations heritable Change that randomly occurs in the DNA of an individual that is ______________ (gametia) Only ______________ source- of new alleles (genes) > - variations Ex) Norway rats (some had a resistance to warfarin poison) When warfarin was applied, those resistant to the poison survived, reproduced and passed on the allele. This selective advantage changed the allele frequency of this characteristic allele frequency of resistant trait A Neutral: mutations usually occur in Beneficial: mutations are rare but the Harmful: occur frequently, but the FOR environment selects against them non-coding ________________________ environment selects them and, and therefore, alleles that result regions of genetic material and do therefore, alleles resulting from them not benefit or harm the organism accumulatel ______________________ over time from them are _______________ rare increase Ex) Cystic Fibrosis/genetic disorder Ex) Attached Free Ex) frequently us Bacteria resistance to. 3 Mutations occur Earlobes cunattached) but individuals disease , antibiotic (benefical for with bacteria) + resistant trait hardly survive - cannot be inherited. is passed on to offspring Remember, mutation rate is pretty low in individual cells so, the impact of brand-new mutations on allele frequencies from one generation to the next is usually not large. However, natural selection acts on the results of a mutation and can be a powerful mechanism of evolution. Helpful Ex) Sickle Cell and Malaria O Normal RBC (Sickle cell RBC -> less SA , less oxygen Heterozygous Advantage: Inheritance is codominant so if you are heterozygous, some of your red blood cells are normal and some are sickle. Sickle cells can’t be infected by a mosquito because it does not carry enough oxygen. Natural Selection advantageous Organisms with _____________________________ survive heritable traits are selected for, ___________________ reproduces and ____________________ with o springs passing their traits to their ________________________ & organ Selective pressure selects FOR or AGAINST specific traits that allow the organism to survive and reproduce viable offspring advantageous organisms survive t reproduce ↳ lived long enough to reproduce again 8 Activity: What are some selective pressures that select FOR or AGAINST specific traits: Abiotic: Biotic: of sunlight ↳ Predator 4 Invasive species 4 Drought is Availability prey - Flood 3 Parasile/Commensalism 3 Temperature u Competition Ship Natural Selection and Darwin’s Journey HMS Beagle (five year trip) Round-the-world including the Galapagos Islands Published “The Origin of Species” Activity: Watch the following video and summarize the information. u Island tortoises are not identical to continental tortoises 32 different shapes of shells are founded to adapt to their environment Islands lower shell due to lower vegetation. Continental as a peak in shell due to From his many observations Darwin came up with several conclusions: higher vegetation (stretch TIME organisms evolve over ______________ necks) gradually (slow) change occurs ______________________ all organisms come from a __________________ common ancestry species multiply and evolve into _______________ new species > - macroevolution / speciation adaptive surviving organisms have traits __________________ to their environment and pass those characteristics on to the next generation Ex) Darwin observed variation of finches → Beak suited for the type of food they are eating 3 Modes of Natural Selection: peak in the C middle-most common phenotype Directional Disruptive Stabilizing extremel extreme 2 9  Directional: Disruptive: Stabilizing: Lighter phewetype is Darker phenotype is selected iCommoan selected FOR AGAINST O 0 When natural selection selects for the extreme phenotypes and acts to Favours the ______________ common results in a shift in _________ ONE phenotype remove the most _________ common extreme aspect of a trait Selects against the characteristics. moves the curve in one characteristics that differ from - The _________________ extremes may direction - become separate species. Macro the most common (extremes) Ex) Ex) Human birth with are selected Ex) Ground findes with Taller girattes medium-sized beaks almost medium weight is selected for more than short girates hard with ↳ large brains in humans extinct because only available survival %. greatest soft seeds infection or are I small- easy s ↳ long trunks + large size elephants of is leads to speciation us Salmon size reduced due to overfishing small/large beaks ↳ large-hard to deliver. Non-random Mating Inbreeding Preferred Phenotypes related closely when __________________________ individuals Selecting a mate based on physical and behavioural traits (phenotypes) breed together Individuals tend to mate with those who live Assortative Mating: When individuals mate with partners nearer to them, than with more distant members that are like themselves in certain characteristics of the same population. Members that are closer Ex) Jumping spider: larger females are better together are more likely to be more closely equipped to resist male courtship attempts related Ex · family members and only largest males are able to mate with them share similar genotypes so the frequency of the homozygous genotype increases __________________ Disassortative Mating: phenotypically dissimilar harmful ____________________ recessive alleles are more organisms mate together frequent, therefore more likely to be expressed - Dog in China Ex) Shar-pei · Inherited genetic mutation enhanced through inbreeding , increase production of Random mating hyaluronic acid- skin disorders any male/female is have Ex) “The Royal Disease” X linked recessive hemophilia equal chances of Increased frequency through inbreeding mating CA homozygous genotype) Trace hemophilia through Queen Victoria's descendant. 10  NOT With inbreeding and preferred phenotypes, does ____________ alter allele frequencies in a population homozygous However, it will increase the number of expected______________________ individuals. Therefore, it doesn’t cause microevolution by itself, but contributes to the mechanism of natural selection Sexual Selection ONE Certain characteristics (physical and behavioural traits) are actively sought out by ____________ sex (usually female the ________________) One result is sexual dimorphism: a marked difference in mates and females phenotypes Caribou their antlers to fight other males. T use Ex) Females will only mate with stronger males More colorful females , weaker Stronger will mate with multiple Do ones male peacocks to NOT mate. attract females Sexual Selection vs Natural Selection: fitness Both focus on increasing _______________: the ability of an organism to pass on its genetic material to its offspring or relative contribution of viable offsprings. While natural selection focuses both on survival and reproductive success, sexual selection doesn’t necessarily focus on an organism surviving longer, just its ability to pass on its traits. only reproduction not survival Preferred Phenotypes vs Sexual Selection: ALL __________ individuals are still mating in preferred phenotypes so allele frequencies does NOT change specific Only _______________ individuals are mating in sexual selection so allele frequency DOES change. Cadvantageous 11  Genetic Drift small Change in gene or allele frequencies in ________________ populations random Alleles can be lost at _______________ Chance (by ________________) from the population, causing dramatic changes in genetic makeup of the population Can result in alleles disappearing completely or becoming very common uncertainty The smaller the sample, the greater ________________________ of your results Bottleneck Effect Founder Effect temporary Large, ______________________ reduction in By chance, a small number of dispersed the population that may result in significant individuals establish a ____________ new population genetic drift (founders) at a distance from the original Disease ○ By chance alone population colonization migration ○ A severe environmental stress nearly Drought , Causes a limited number of alleles to be present wipes out a population Starration , > - (____________ loss of genetic diversity) Some alleles may be lost forever because only a If the founders have rare alleles, then rare alleles - small number of individuals survive and will increase in frequency - reproduce (all done randomly) islands Occurs frequently on ________________ randomly selected all swirl 800 6 000 ⑳ o ⑧ ⑳ 6 O O recessive trait 00 more common Swirl + solid O O ① ⑭ ⑪ P O O : 80 ⑪ ⑳ ⑪ G O Original BottleneckingSurinone Generations after O ⑪ Ex) ↳ 30000 northern elephants today are all descendants Ex) Amish population who in Pennsylvania to all descended who have of 20 individuals from 30 people imigrated us , led is thousands years ago a bottlenecking event polydactylism (extra Singer) to small population of cheetahs that were inbred a know Amish population have 1/14 polydachylism ↳ cheetahs being 99 % homozygous gene loci vs. Normal 1/1000. Gene Flow Opposite Inbreeding > - : Movement __________________ alleles (flow) of _______________ from one population to another by movement of individuals fertile Needs to have a migration of a _____________ individual to a new population, or the transfer of gametes, between populations Genetic Drift = ↓ Diversity allele frequency Alters the _______________________________________ Gene Flow = ↑ Diversity Increases __________________ genetic diversity of the population unrelated Ex) Prairie Dogs/lions-males (adult) leave to form new prides with genetically females. Grey Wolf - a lone grey holf can travel sookm in search of a new territory or breeding partner - brings holf to a population of wolves nearby = brings new alleles into gene pool of nearby population. 12  Speciation (Slideshow 6) Species morphological Carl Linnaeus defined a species as: A group defined by __________________ differences from all other life forms. Modern definition of species focuses on ______________ and biochemistry genetics Biological Species Concept: GA species is....... Over time a Population where individuals are able to ___________________ interbreed viable to produce ____________ offspring population is gene pool Populations that can reproduce will share a _____________________________ allowed and will slowly become no longer to I with other species reproductively isolated breed,mate _______________________________________________ from other such groups Speciation: The formation of new species Macroedation > - In order for speciation to happen, you need a mechanism of evolution and isolation. There are 2 modes of speciation: i e. natural selection selects for. speciation - extinction against - Allopatric Speciation Sympatric Speciation Most new species form when a single species is separated Individuals within a population become into two geographically isolated populations by genetically isolated from the larger population barriers without geographic isolation no geographical ____________________________ ___________________ barriers physical _________________ separation prevents the exchange of A population of a species within a physically genetic information. ____________ geographical region splits into single Allele changes within each population eventually cause separate gene pools and forms separate Reproductivelythe gene pool of the populations to be so distinct that species. isolatedthey wouldn’t be able to interbreed when re-introduced Ex. Jumping spiders Ex) of antelope How does this happen? Assortative Mating (large Two closely-related species Non-random mating (preferred phenotypes) large) · squirrels live on opposite side of a great canyon Different selective pressures (at either end. ie. could alter the alleles of the population) ↳ South A Kanisi. environmental =. a North Other reproductive isolating mechanisms = A lencurus. stress Birds and that the other species can cross · Canyon have not diverged into a different other sides. species on Ex) Ancestors of apple maggot flies laid their eggs only on hawthorns. Today, flies lay eggs on behavioral BOTH hawthorns and domestic apples (introduced to adaptation ↓ America by immigrants). Females lay eggs and males look for mates on the type of fruit they grew up in. barrier Physical Hawthorn flies end up mating with other hawthorn flies and apple flies end up mating with other apple flies. Reduced gene flow may lead to speciation Reduced Laideggon apples gene flow = > Apple maggot flies less movement - Hawthron indegg of alleles flies hawthron on Ex) Polyploidy in Plants withon flies. between 2 populations. Capple/hav 14. ron)  tolerant to man disjunction plants are more than humans/animals gameles. During meiosis, if the cells fail to separate properly -2n (nondisjunction), cells become diploid instead of an un haploid. Their ability to self-fertilize enables these parent - an "tetraploid diploid cells to fuse with one another to produce tetraploid species Practice: Consequences of Human Activities on Speciation 1. Hypothesize on how human activities would have a consequence on speciation and extinction. ↳ Allopatic > - human activities create physical barriers (geographical isolation) Natural andhargenpoRFIMention Selectionspeciesare geographicallyseparated 2. Explain how the mechanisms of evolution interact with these human actions. Use specific vocabulary. a. Converting large stretches of wilderness into croplands, areas of recreation and tourism, and urban subdivisions Forced migrate Genetic Drift or gene flow · to -. ↳ Genetic Drift original species settle in : new land a - Decreased diversity ↳ Gene Flow of original species : mix with other populations Increase biodiversity. b. Building roads Natural Selection s species better adapted to road environment (i warning when crossing roads) · -. e.. can survive better · Allopatric speciation separation of 2 gene pools Reduced flow between 2 species c. Flooding largegene · areas of land by building dams and hydroelectric power generators · NS- Aquatic-adaptive species survive better (better reproduce pass on allele to offspring - Microerd) · Genetic Drift s a chance event (flood) decreases or eliminates Certain alleles in a population is Decreased Div. Reproductive Isolating Mechanisms (Slideshow 7) It is easy to see how populations become reproductively isolated in allopatric speciation since they are physically separated, but how do populations become reproductively isolated in sympatric speciation, when they are in the same geographical area? Reproductive Isolating Mechanism: any behavioral, structural or biochemical trait that prevents individuals of different species from reproducing successfully mating 1. Prezygotic: Isolating mechanisms that prevent ___________________ fertilization or ______________________ 2. Postzygotic: Isolating mechanisms that prevent _______________ viable fertile and ________________offspring 3 lived h able to reproduce long enough to reproduce again physiologically. O Ecological + egg - # are 08 Reproductive - - Prezygotic - - Temporal Behavioral 3 Mahin ↓ nation zygote offspring Isolating Mechanisms 2 Y Mechanical Gametic Fertilization prevention Sperm 3 Prezygotic ↳ Montalh PostzygoticZygote Postzygotic & Infertility Hybrid 15 Prezygotic Reproductive Isolating Mechanisms Mating Prevention Example 1 Ecological habitats Species that occupy separate __________________ Aor Birds that live in high Isolation niches separate ____________ of the same habitatNdo not meet to altitudes (mountain birds) do not mate mate with birds living in low altidudes. u do not encounter each other. 2 Temporal Temporal conditions refer to time of day, seasons or different Isolation years. times - Different species mate at different ____________ 3 Behavioural The _____________________ courtship and ____________________ mating cues Eastern/Western meadowlark Isolation for attracting a mate are very specific for each species. are identical except having different - Distinctive mating rituals in one species will not be to attract mates songs. recognized by another. Fertilization Prevention Example 4 Mechanical - ____________________ structures differences in reproductive organs 'Bush babies' are divided Isolation - prevent copulation into several species based doesn't fit lock physical ↳ key in the on distinctively shaped genitalia 5 Gametic - molecular Prevents fertilization at the _________________ level · Female immune system recognizes Isolation - Egg and sperm fail to fuse as foreign and attacksit - sperm chemical Sperm/pollen cannot adapt to female reproduct tract Some are ↳ acidic Postzygotic Reproductive Isolating Mechanisms In some cases, mating and fertilization between different, but related, species can occur. However, if the offspring are not viable and fertile, then the two species continue to be considered as different. Examples 1 Zygotic zygole Fertilized _____________ die before birth sheeps and goats can Mortality Chromosomes - _______________________ are not compatible make but the zygote is (i e.. Wrong#) not viable (dies before birth) 2 Hybrid before birth or is born The embryo develops and dies __________ Lions + Leopards have Inviability that have short Has not weak lived alive, but the hybrid is _________ , experiences reduced hybrids lifespan and die before long enough survival and does not survive to __________________ reproduce maturity. 3 Hybrid Hybrids do develop normally and reach sexual maturity, but Mules are mated from horse Infertility characteristic (do not produce viable ______________) and donkey they have Sterile are _____________ gametes , Are not able sterile and of both, but are to gametes produce cannot breed. physiologically 16 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