Evolution A process of change through time

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Evolution -is the change in the inherited traits of a population of organisms through successive generations. This change results from interactions between processes that introduce variation into a population, and other processes that remove it. As a result, variants with particular traits become more, or less, common. A trait is a particular characteristic—anatomical, biochemical or behavioral—that is the result of gene–environment interaction.

Or……. Descent with modification

Evolution Definition: the change in genetic composition of a population of organisms over time Microevolution: change in a population’s Frequency of alleles Macroevolution: multiplication of new species =Diversity

Charles Darwin First Scientist to study evolution on the Galapagos Islands Aboard the HMS Beagle December 1831 to October 1836

On the Origin of Species, published on 24 November Evolution occurs because of Natural Selection, with nature acting as the selecting agent. Organisms better adapted to the environment survive and reproduce more successfully than less-well adapted organisms.

Theories of Evolution Jeane Babtiste Lamark The Principle of Use and Disuse: New structures developed in an organism during the course of evolution because they were needed and unused structures were lost. Inheritance of Acquired Characteristics: Characteristics During a lifetime were passed onto offspring.

Thomas Malthus ( ) Population growth not always desirable Population increases geometrically; food supply increases arithmetically

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Sir Charles Lyell ( ) Geologist The earth was much older than originally thought – Time is essential

Natural Selection Populations change in response to their environment. Acts on phenotype of an organism. (Not genotype)

Theory of evolution by natural selection –Proposed by both Darwin and Alfred Wallace –Based on four observations Genetic variation exists among individuals Reproductive ability of species causes its populations to geometrically increase Organisms compete for resources Offspring with most favorable characteristics is most likely to survive

Speciation Formation of a new species

What’s a species? A population whose members may breed and produce fertile offspring … No not a liger! Nor a mule!

Adaptations(Evolutionary) Inherited characteristics that enables a species to survive and reproduce EX: Darwin’s finches… Inheritable: variation in genetics: Mutations, recombination of genes, random movement of chromosomes during meiosis

Reproductive Isolation Separation of two groups over a long period of time may Result in change in the genetic makeup of the two groups Making them unable to reproduce with each other.

Geographic Isolation A body of water or mountain range separates a population of a species resulting in evolution of new species.

–Artificial selection Breeders developing many varieties of domesticated animals in a few generations Plant varieties, such as kale and broccoli, developed from wild cabbage

Artificial selection in Brassica oleracea

Mustard Evidence

22 12 EVIDENCE OF EVOLUTION

Geological Record: Through radioactive dating the oldest rocks in the earth’s crust, the age of the earth is 4.5 – 5 billion years old. Fossils: Traces of once living organisms In Rock

In AmberIn Ice Petrifaction 

Comparative Anatomy: Organism with similar body Structure evolved along the same line. Homologous Structures: Evidence of common ancestry.

Analogous Structures : Same function, structurally different. Show no common ancestry.

Vestigial Structures: Structures in an organism through evolution have been lost or reduced in size because they were no longer necessary trait for survival.

Embryology

Bacterial Antibiotic Resistance

Modern Theories of Evolution A change in the DNA of an organism over a period of time Sources of variation Sexual Reproduction: A recombination of alleles. Random and spontaneous gene and chromosome mutations.

Natural Selection is one of the basic mechanisms of evolution, along with mutation, migration, and genetic drift. Darwin's grand idea of evolution by natural selection is relatively simple but often misunderstood. To find out how it works, imagine a population of beetles: There is variation in traits. For example, some beetles are green and some are brown.

There is differential reproduction. Since the environment can't support unlimited population growth, not all individuals get to reproduce to their full potential. In this example, green beetles tend to get eaten by birds and survive to reproduce less often than brown beetles do. There is heredity. The surviving brown beetles have brown baby beetles because this trait has a genetic basis.

End result: The more advantageous trait, brown coloration, which allows the beetle to have more offspring, becomes more common in the population. If this process continues, eventually, all individuals in the population will be brown. If you have variation, differential reproduction, and heredity, you will have evolution by natural selection as an outcome. It is as simple as that.

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Chromosome numbers in the great apes: 46 human (Homo)46 chimpanzee (Pan)48 gorilla (Gorilla)48 orangutan (Pogo)48 Testing the Evolutionary Hypothesis of Common Ancestry

Testable prediction: Testable prediction: If these organisms share common ancestry, the human genome must contain a fused chromosome. Testing the Evolutionary Hypothesis of Common Ancestry

Chromosome numbers in the great apes (Hominidae): 46 human (Homo)46 chimpanzee (Pan)48 gorilla (Gorilla)48 orangutan (Pogo)48 Testable prediction: Testable prediction: The marks of that fusion must appear in one of the human chromosomes. Centromere Telomere Ancestral Chromosomes Fusion Homo sapiens Centromere #1 Telomere sequences Centromere #2

Homo sapiens centromere #13 (inactive) Telomere sequences Human Chromosome #2 shows the exact point at which this fusion took place centromere #12 (active) Hillier et al (2005) “Generation and Annotation of the DNA sequences of human chromosomes 2 and 4,” Nature 434:

Fossils show life Started…. As bacteria and archae Then invertebrates Then vertebrates: Fish, amphibians, Reptiles, birds and Mammals…….

“There is grandeur in this view of life; with its several powers having been originally breathed into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most wonderful and most beautiful have been, and are being evolved.”

42 Topical Generalization # 1 Evolution is the result of natural selection. Guiding QuestionsWhat are selective forces?Why is natural selection the mechanism for evolution?What is an adaptation?How do behavioral, physiological, and structural adaptations differ? In terms of evolution, can an individual organism adapt?What defines a species?How do selective forces guide evolution?What is genetic fitness?

43 Topical Generalization # 2 Variation within populations can arise through different processes. Essential/Guiding QuestionsWhat built in mechanisms do organisms have to ensure variation occurs?What are sources of variation?What is a mutation?What is a mutagen?Are mutations always bad?

44 Topical Generalization #3 There is scientific evidence to support evolution. Guiding QuestionsWhat evidence do scientists use to support the theory of evolution?How has evidence for evolution changed as technology has changed?Who are the initial key contributors to the theory of evolution? Why can’t pieces of evidence be used individually to support evolution?

45 Evolution Vocabulary Also go to Quizlet activity Charles Darwin Jean Baptiste Lamarck Thomas Malthus Charles Lyell Galapagos Islands macroevolution microevolution fossil embryology homologous vestigial analogous structures molecular evidence phylogenetic trees selective forces adaptation behavioral adaptation physiological adaptation structural adaptation genetic fitness species genetic fitness extinction natural selection mutation mutagens