What is Evolution? Evolution- the genetic change of populations over time Population- group of organisms of the SAME species that occupies certain area Species- organisms that can interbreed and produce FERTILE offspring –Ex) populations in Sauerman Woods Crown Point -whitetail rabbits-deer -whitetail rabbits-deer -sparrows-squirrels

Liger (lion and tiger)-infertile

Cama (camel and llama)-infertile

How Do We Know Populations Evolve? Population Sampling- technique uses part of population to represent whole population Capture 100 random rabbits –These rabbits are a representation of all the rabbits in the area. –We can study many things within this group…

Genetics of the Population… Gene Pool- all of the genes of every individual in population sample Frequency- how often something occurs Population genetics involves studying the frequency with which certain alleles occur in a population’s gene pool In 50 years, will the  allele frequencies be the same?

Hardy-Weinberg Hardy-Weinberg Equilibrium Principle – frequencies of the dominant and recessive alleles in a population change in time due to 5 things: Hardy-Weinberg Equilibrium Principle – frequencies of the dominant and recessive alleles in a population change in time due to 5 things: MutationsMutations MigrationMigration Natural selection (survival of fittest)Natural selection (survival of fittest) Small populationSmall population Non-random mutationNon-random mutation If these things occur, then the frequencies change and a population evolves If these things occur, then the frequencies change and a population evolves

Quiz ______________=the genetic change of populations over time. _____________ =group of organisms of the SAME species that occupies certain area. _____________=organisms that can interbreed and produce FERTILE offspring

Quiz __________=technique uses part of population to represent whole population. __________=all of the genes of every individual in population sample. frequencies of the dominant and recessive alleles in a population change in time due to 5 things: frequencies of the dominant and recessive alleles in a population change in time due to 5 things: Mutations, Migration, Natural selection, Small population, Non-random mutationMutations, Migration, Natural selection, Small population, Non-random mutation

History of Evolutionary Thought Before 1850, most people believed… –Earth formed by supernatural events and never changed –Earth only a few thousand years old –Each species was made to fit its environment –Species never changed and did not go extinct

Early Scientists’ Ideas Darwin deserves credit for the Theory of Evolution as we know it today He was not the first to come up with the idea: –Carolus Linnaeus proposed a new system of organization for plants and animals based on their similarities (noticed relationships) –Erasmus Darwin considered how organisms could evolve through mechanisms such as competition –Jean-Baptiste Lamarck presented evolution as occurring due to environmental change over long periods of time

Carolus Linnaeus Developed a classification system for the huge variety of living things he found –Wrote book Systema Naturae in 1735 to reveal his classification system –There are currently 1.9 million species that have been identified using his method –Linnaeus’s system of classification reflects evolutionary relationships

Jean Baptiste Lamarck A French naturalist who proposed that populations of species evolve His idea proposed: –Changes in an environment cause an organism’s behavior to change, leading to greater use or disuse of a structure or organ. –The organism would pass on these acquired changes to its offspring, so a species would change in time. –Idea called “Evolution by inheritance of acquired characteristics” –Wrong on several accounts

Charles Darwin At 22, was invited to sail on the “HMS Beagle” –Was going to school to be a minister-believed God created each species to match its habitat and they never changed. –Thought Earth was about 6,000 years old and didn’t change, just like everyone else.

Darwin’s Observations One place of note that he visited was the Galapagos Islands During journey, he made observations and recorded them in a journal. Darwin observed fossil and geologic evidence supporting an ancient Earth.

Darwin’s Finches When Darwin traveled to the Galapagos he took interest in the finches He noticed the finch species on the islands were different, but all resembled one from S. America. Darwin thought some migrated and new species evolved.

Darwin’s Finches This is what Darwin proposed: –Finches migrated from South America to the islands. –Populations on different islands adapted to different environments and food sources they found. –Those that could survive passed on their genes. –Those that couldn’t survive perished.

Darwin’s Finches Over time different mutations accumulated in the different finch populations on the different islands. Over time different mutations accumulated in the different finch populations on the different islands. The populations diverged, or became more and more different from each other. The populations diverged, or became more and more different from each other.

Darwin’s Finches The populations on the islands became so different they no longer mated if they met Several new finch species evolved from a common ancestor from S. America This is an example of macroevolution.

Recent finch research

Speciation Geographical isolation- members of a population are separated geographically –Major step that leads to speciation –Due to volcanoes, earthquakes, flooding, etc. –Can lead to divergence and then speciation

Artificial Selection Artificial selection- human intervention in animal or plant reproduction to ensure that certain desirable traits are passed on Instead of NATURE selecting which traits are favorable, HUMANS selectively breed those animals with favorable traits Ex. dogs or racehorses Darwin bred pigeons to explore this idea. explore this idea.

Darwin’s Results In 1859, Darwin published The Origin of Species His book stirred up controversy Idea called “Evolution by natural selection” Darwin Video

Darwin’s Book Explained Natural Selection Natural selection- organisms best suited to their environment survive and reproduce –Darwin’s proposed mechanism of evolution –Survival depends on the particular environmental conditions a species finds itself in—nature! –If the environment changes, so do the populations that live there Adaptation- using inherited genetic characteristics to increase chance of survival in new environment Natural Selection and Salamanders Natural Selection and Salamanders

Natural Selection Three conditions necessary for natural selection to occur: –Genetic variation: Individuals within a population must be genetically different ****Random mutations are the raw material for evolution to occur!!!!!!! –Overproduction of offspring: More organisms are born than can survive –Differential reproduction: Certain traits enable individuals to survive and have more offspring than others

Result of Natural Selection - Genes that help a population survive in their conditions stay in their gene pool, while “unfavorable” genes gradually decrease in frequency - This causes changes in the genetics of populations  EVOLUTION!!!!! - As new mutations accumulate over a long time, the new populations no longer can mate with the original they started as. New species have formed!

Whose idea for evolution is this?

Types of Evolution Evolution - genetic change of a population of organisms over time  descent with modification Micro evolution: Small genetic changes of a population Shorter amount of time Peppered moth simulation was microevolution

Types of Evolution MACROevolution-When new species are formed over long periods of time –Due to tremendous amounts of accumulated genetic changes in a population –Speciation- formation of new species due to accumulated microevolution and mutations

EVOLUTION by natural selection MACROevolutionMicroevolution Changes in gene frequencies in a population Shorter times Examples: Peppered moth and Bengal tiger Accumulated microevolution and mutations to form whole new species Longer times Examples: Darwin’s finches and geographical isolation

Evidence for Evolution Three types of evidence: –Fossils –Anatomical –Molecular

Fossil Evidence Transitional species- species that have been found in the fossil record that are intermediates between two other species in the evolutionary process –Radiometric dating- a dating technique that measures amount of radioactive material in a rock or fossil –Relative dating- a dating technique that estimates the date of a fossil by relating it to the age of the layers of rock around it

Fossil Evidence To fossilize an organism must be buried by sediment –In swamps, mud, tar pits, or the ocean bottom –Hard stuff fossilizes (bones, nails) –Radiometric and relative dating are used to find out how old the fossil is Relative Dating Radiometric Dating

Fossil Evidence Fossils show: –Life has been around for millions of years –Transitional species link older to newer species –Darwin proposed the idea of transitional species, though he had no evidence –Today we have evidence: Archaeopteryx Tiktaalik Fossil, etc.Tiktaalik Fossil Whales

Anatomical Evidence Anatomical evidence- evidence for evolution which is based on similarities and differences between the physical structures of different species. What can we tell about the relatedness of the three species below?

Anatomical Evidence Homologous structures- structure is the same (homo) but not function –Bird wing, dolphin fin, and a human arm –Function these structures is not the same! –Show that these species shared a common ancestor –Similar structures resulted from accumulated mutations and modifications

Homologous Structures

Anatomical Evidence Analogous structures- structure different but serve the same function –Function = flight –Butterfly wing, bat wing, fly wing  These structures, although they have the same function, are not built the same! similar functions  similar external form  different internal structure & development  different origin  no evolutionary relationship

Analogous structures Solving a similar problem with a similar solution Don’t be fooled by their looks!

Anatomical Evidence

Vestigial structures- structures that no longer serve a function These structures are the remnants of an evolutionary past and show common anatomy with other species

Molecular Evidence Molecular evidence- evidence concerning the comparison of DNA and protein molecules between species Ultimate tools for scientists studying evolution Same genetic basis for all organisms: A, C, T, and G shows we are all related

Molecular Evidence Mutations and sexual reproduction are a cause of variation in a species’ DNA DNA  mRNA  protein –Transcription- copying the DNA code into mRNA –Translation- converting the code of mRNA into a long chain of amino acids  protein –Differences in DNA are seen in differences in protein and therefore, traits

Molecular Evidence Species with more similar DNA are more closely related on the evolutionary tree –Less time since they split to accumulate mutations (and, therefore, differences) –Common ancestor- any species in the past from which two or more related species has evolved –Evidence for EvolutionEvidence for Evolution = speciation event = mutation

How did life begin? 1.)Extraterrestrial origin (Big Bang Theory) 2.)Creation—”divine forces” 3.)From non-living matter (“Chemical Evolution”)-- Organic compounds assembled creating 1 st bacterial cell

How Modern Day Biologists Classify 1. Comparing anatomy (physical traits) 2. Looking at genetic similarities & differences 3. Biochemical make-ups 4. Behavioral similarities Origin of Life Video

Cladograms Cladogram- a branching diagram that shows evolutionary relationships We use taxonomy – the science of classifying living things, to help us determine the cladogram