Evolution Evolution Life on earth bean over three

Evolution

Evolution Life on earth bean over three billion years ago with the appearance of simple, single celled organisms Over time more complex singled-celled organisms developed About one billion years ago, increasingly complex multicellular organisms began to appear The change in species that has occurred over time is known as ________ evolution It is a well documented subject from a wide variety of sources and is considered the central _______________ of biology Unifying theme

Evolution Since so much evidence has supported this subject theory evolution is now considered a ________. tested A theory is a concept that has been ________ confirmed and ________ in many ways and can be used by scientists to make predictions about the natural world. Among different organisms, theory of evolution explains changes in: and organ function Cell _______________________ Bone structure Biochemical _______________________ makeup _____ behavior _______________________ _______________________

Darwin’s Theory of Evolution Charles Darwin In 1859, the English naturalist __________ proposed a theory to explain how organisms changed ________ over time observations of He based his theory on ________ animals plants ________ and ________ that he studied all over the world

Darwin’s Theory of Evolution was based on Differences variations ________ or ________ among offspring His idea was that evolution was controlled by “nature” ________ rather than people survive Individuals that ________ in an environment are Breed (reproduce) and pass their genetic able to __________ information to t he next generation Not successful in the environment often Those that are ________ reproducing die without ________ Beneficial traits As a result __________ will become more and more common with each generation and Non-beneficial traits will tend to become less common __________ Natural Selection to explain Darwin used the term __________ his theory

5 Key Concepts of Darwin’s Theory of Natural Selection Darwin’s Theory contained the following ideas that are vital to the process of evolution: 1. overproduction ________ - in each generation, a species has the More offspring than can potential to produce __________ survive possibly ________ reproduce If all offspring lived long enough to ________, any one of the species would cover the earth in a short time. For example: bacteria, insects, dandelions, and rabbits have high reproductive rates. If these organisms all survived, they would overrun the earth. This does not happen!! Stable environment In a _____________, the population of a same species remains about the ________ from one year to the next.

5 Key Concepts of Darwin’s Theory of Natural Selection for Survival or competition - Since living 2. Struggle _________________ shelter space food water __________, and oxygen _____ are limited, offspring in each generation must compete amongthemselves _______________, and with other species _____ too, for the necessities of life. Offspring all have to cope with Environmental conditions disease temperature _____________ such as parasites ________, predators _____, and __________, Best suited Those that are __________ or Best adapted __________ to their environment are more likely __________ to survive.

5 Key Concepts of Darwin’s Theory of Natural Selection variation in any species, the characteristics 3. _______________ of the individuals are not exactly alike. Some squirrels may have sharper or longer claws, lighter or darker fur, bigger or smaller ears, and so on. Genetic variations These differences are due to __________ - the unique _____ combination of traits each organism inherits from their parents. survive Any trait that helps an organism _____ and reproduce _____ under a given set of. Environmental conditions Adaptive values ____________ is said to have __________. A rabbit’s ability to blend in with its surroundings may Fur allow it color to escape its predator – the fox. The ________ for the rabbit has adaptive value.

5 Key Concepts of Darwin’s Theory of Natural Selection Survival of the fittest and Natural selection 4. __________: variations adapted because of _____, some individuals will be better _____ to survive and reproduce in greater numbers fit those less _____. than success This is called. Reproductive ___________. The better variations inherit _____ these favorable adapted individuals _____.

5 Key Concepts of Darwin’s Theory of Natural Selection 5. Speciation _____ - over many generations, Favorable variations unfavorable accumulate gradually ____________________ in the species and _______ ones disappear. Eventually the accumulated changes become so great that a New species ________ will evolve.

Examples of Darwin’s Theory of Natural Selection 1 – The Pepper Moth According to Darwin’s Theory, a Changing environment behavior traits ____________ will select certain _____ and _____ of organisms and allow them to survive and reproduce. Pepper Moths

Examples of Darwin’s Theory of Natural Selection 1 – The Pepper Moth frequencies of the light trait and dark The changing ______ trait in the peppered moth population are due to Natural selection _________ When the tree color takes on a lighter shade, the light _____ trait will be naturally selected When the tree color takes on a darker shade, the dark _____ trait will be naturally selected Light-colored Peppered Moth Soot-covered bark of tree Dark-colored Peppered Moth

Examples of Darwin’s Theory of Natural Selection 2 – Resistance to Antibiotics are used a lot, and sometimes inappropriately Antibiotic resistance is becoming a common problem in many parts of the United States mutate It occurs when bacteria in your body _____ (a random change in the DNA codes) so that antibiotics don’t work effectively to fight them anymore. This can happen when bacteria are repeatedly _____ exposed to the same antibiotics or when bacteria are Left in your __________ after you have been taking antibiotics body (such as when someone does not take the full course of their antibiotic medication) resistant bacteria can _____ multiply These _____ and become 100% resistant to the antibiotic in the a population ________ future

Examples of Darwin’s Theory of Natural Selection 3 – Galapagos Finches The finches on the Galapagos Islands are adapted to eating different types of food

Examples of Darwin’s Theory of Natural Selection 4 – Giraffes

Selected Behaviors building behavior Nest ____________ in Birds – the birds which build the best nests are better able to reproduce behavior Fighting __________ among the walrus populations for a harem of females – the stronger, healthier males mate with the most females blinking rate behavior between male and Correct __________ female fireflies to find each other to mate

Sources of Variation Theory of evolution As Darwin developed his __________ following his return to England in 1836, he worked under a serious disadvantage heredity He did not know how _____ worked. Although Gregor Mendel’s work on inheritance was published in the 1860’s, which was during Darwin’s lifetime, its importance was not recognized until after 1900. Without an understanding of heredity, Darwin was unable to explain two important factors: Source of variation 1. He did not know the __________ that was so central to his theory. Inheritable traitswere 2. He could not explain how ________ passed from one generation to the next. ? ? ? ?

Genetic Basis for Variation Leading to Evolution During meiosis _____ (remember crossing over), new combinations of existing genes occur when creating shuffling eggs and sperm. This is called Genetic _________. These genes are passed down to the offspring fertilization ________ - even more genetic variety occurs due to a female’s egg joining with a male’s sperm creating a unique set of chromosomes in the zygote. mutations of genes in thegametes Random __________ (eggs and sperm) can create new traits in the offspring. The mutations are changes in the ________ Base sequence of the DNA molecule that an occur randomly or from radiation chemicals exposure to _____ and _____. Remember, a mutation is a change in the base sequence of the DNA molecule.

Genetic Basis for Variation Leading to Evolution In organisms that reproduce sexually only, changes in cells genes the _____ of Sex ________ can only become the basis for these revolutionary changes. A mutation in a single celled organism can also be passed to offspring by mitosis. When mutations occur in body cells, they can only affect that individual.

Evidence of Evolution fossils Some evidence of evolution comes from _____ Dead organisms that Fossils are traces or remains of _________ have been preserved by natural processes teeth bones These may be _____ or _____ fossilized in sediment _____ These fossils form a series of clues to the earth’s history, environmentsas well as revealing changes in _______ species _____. Geological record This is called the __________ changes in a species The geological record shows __________ over time.

Evidence of Evolution NEWEST LAYERS OLDEST LAYERS

Evidence of Evolution Scientists find clues to the relationships between organisms through studies ofmolecular _____ andstructural Common ancestry _____ similarities. These similarities show __________. cytology anatomy 1. Comparativehomologous _____ and _____ studies the cell anatomy function structures of _______ structures, structures similar in _____ but different in _____. These Common studies canancestor show these organisms evolved from a __________. Although these organs of locomotion function in different ways, they appear to have developed from the same original structure

Evidence of Evolution 2. Comparative embryology ________ comparing embryos _____ of organisms for similar structures to see if Common they share aancestor __________ _

Evidence of Evolution biochemistry - comparing the 3. Comparative ________ DNA proteins molecular makeup such as _____, _____ and other body chemicals. The greater the similarity, the more closely related the Common ancestor organisms are. They also share a __________.

Evolutionary Models Creating a family tree – a simple diagram can be used to represent the evolutionary relationships among different species

Evolutionary Models A, B, C, and D represent 4 living species. E, F, and G represent ancestral forms of these species that are extinct. Organisms B and C are most closely _____ related because they evolved from their common ancestor E What ancestor is organisms A F most closely related to? _____ Why would organism D be the least related to organisms A, B, and C? A, B, and C are related to F _______________ D is on a different branch from A, B, and C _______________ D evolved from G the longest time ago ______________________________ __________

Evolutionary Models – Some Questions What is the ancestor of all of these organisms? Ancestral colonial protist ____________ __ Are the mollusks more similar to the annelids or annelids the round works? _____ Which organism is the least related sponges to all other organisms? _____

Human Influence on Evolution breeding Selective __________ or artificial selection is when humans environment _____, not the. Natural __________, select the desirable traits and decide organisms that have certain _____ which ones will survive and pass on those traits to their offspring _____ This results in livestock breeds and crops that are different _____ from their wild ancestors (e. g. domestication) engineering - humans altering Genetic __________ genes (e. g. cloning, recombinant DNA, selective breeding) to produce new varieties of plants and animals.

Evolution and Biodiversity biodiversity is all of the different varieties and ________ forms of life found on earth. Biodiversity increases the chances for some species Changing environment to survive in a ____________ stable Biodiversity makes an ecosystem more _____

Extinction extinction ________ is the disappearance of an entire species. Generally, extinction occurs when the environment changes. When a species traits (characteristics) do not allow it to survive in a new environment, the species will become extinct. The variation _____of organisms within a speciesincreases _____ the likelihood that at least some members of the species will survive the changing environmental conditions.

Geographic Isolation divided This occurs when a population is _____ by some mountain desert natural barrier, such as a __________, Other body of water river landslide _____, __________, or _____ caused by an earthquake separated groups can no longer As a result, the two _____ interbreed _____. Over a period of time, each group will become _____ toadapted its particular environment mutations Genetic recombination's There will be _____, _____________ Natural selection and _________ in each environment and their Genetic differences ___________ will become so great they will no longer be able to reproduce with each other species Each isolated group will become its own _____