Presentation on theme: "Evolution Evolution is the process by which Populations"— Presentation transcript:
1 Evolution Evolution is the process by which Populations accumulate inheritedchanges over time.
2 Includes three major ideas: Theory of EvolutionIncludes three major ideas:All organisms developed from a singlelife form that lived on Earth billions ofyears ago.All organisms share commonancestors.All species arise from other species.
3 Common Ancestor Scientist have found evidence that all organisms on earth share a commonancestor…all organisms are related.Similar bone structure in the upper arm suggests these animals have a common ancestor.
4 Two processes are necessary for populations to change over time. MutationsNatural Selection
5 Mercury-Poisoning Mutation Mutations are sudden changes in theDNA of a gene. These changes canbe passed on from parent tooffspring.Some mutations are helpful.Some mutations are harmful.Some are neither helpful or harmful.Helpful: such as a mutation that causes bright color patterns in flower petals…all the better to attract pollinating insects.Harmful: Albinism is an inherited mutation. Albinos lack protective skin pigments therefore are prone to skin cancer and do not see well in bright light.Mercury-Poisoning Mutation
6 Finches from the Galápagos Islands Charles DarwinIn 1831 Charles Darwin (22 years old) voyaged on the HMS Beagleto the Galapagos Islands where he made many observationsabout the different species of plants and animals.He was most interested in the birds that livedin the different Islands. In 1859 he wrote a bookcalled “On the Origin of Species”. In it Darwinpresented his theory of evolution by natural selection.H.M.S. BeagleFive year voyage of H.M.S. Beagle ( )Finches from the Galápagos Islands
7 Natural Selection Natural selection is a process in which organisms that are better able to survive and reproduce inan environment are more likely to pass theirtraits on to future generations.“Survival of the Fittest”Traits are selectedTraits must be passed from one generation to the nextChanges occur in response to the environment
8 Adaptation An adaptation is a characteristic or trait that helps an organismsurvive in its environment.Adaptation plays a major role innatural selection.An adaptation makes an organismmore suited to its environment,and therefore more likely tosurvive and pass on its traits tothe next generation.
9 AdaptationsSome adaptations are body parts. Other adaptations are behaviors.A tiger’s teeth are adapted fortearing and chewing. A tiger’s furhelps it blend into tall grasses.Feathers are adaptations used forflight. A bird’s beak is adapted tothe food it eats. What type offood do you think this bird eats?
10 Adaptations Cont. Leaves of green plants are adapted to absorb sunlight. Flowers areadaptations that attract insects thatcan help a plant reproduce. How doyou think a plant’s stem helps it survive?A cactus is adapted to life in adesert. Its thick stems storewater. A waxy coating on the plantreduces water loss.
11 Adaptations Cont. A sea turtle retreats into its shell when it senses danger. What aresome other adaptations of sea turtles?A dandelion’s seeds are easily dispersedby the wind. How do you think thisadaptation help the plant’s species?How do you think thisinsect adapted to livingin or near trees?
12 Peppered Moths The European peppered moth often rests on the trunk of treesand is found in two colors: onelight and one dark.Before 1850, most pepperedmoths were light. After 1850,industry created pollution thatblackened the tree trunks. Lightmoths became rare, while theonce-rare dark peppered mothsbecame more common.
13 Adaptations of Peppered Moths Which moths are better adapted to the tree that they are on?
14 Unpolluted Birch Forest The light variety of the peppered moth on a birch tree trunk.The dark variety of the peppered moth on a birch tree trunk.
15 Polluted Birch ForestThe light variety of the peppered moth on a soot-blackened tree trunk.The dark variety of the peppered moth on a soot-blackened tree trunk.
16 Evolution Mini Assessment Review __________ is the process by which populations accumulateinherited __________ over __________.EvolutionchangestimeThree Major Ideas of the Theory of Evolution:Organisms developed from a single life form that lived on Earth billions of years ago.Organisms share common ancestors.Species arise from other species.
17 Evolution Mini Assessment Review Two processes are necessary for populations to change over time:1. __________ 2. ___________MutationsNatural Selection__________ are sudden changes in the ______________ of agene. These changes can be passed on from parent to offspring.DNA
18 Evolution Mini Assessment Review __________ in 1859 wrote a book called “On the Origin ofSpecies”, it was about __________ by __________ selection.Charles Darwinevolutionnatural__________ is a process in which organisms that are betterable to survive and reproduce in an __________ are more likelyto pass __________ traits on to future generations.Natural selectionenvironmentfavorable (good traits)
19 Evolution Mini Assessment Review An __________ is a characteristic or trait that helps anorganism survive in its environment.AdaptationA species can become __________ if its environment changesto quickly.extinct