* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Chapter 13 - Biology Honors
Survey
Document related concepts
Evolving digital ecological networks wikipedia , lookup
Hybrid (biology) wikipedia , lookup
Coevolution wikipedia , lookup
Evolution of sexual reproduction wikipedia , lookup
Punctuated equilibrium wikipedia , lookup
Natural selection wikipedia , lookup
Theistic evolution wikipedia , lookup
Hologenome theory of evolution wikipedia , lookup
Evolutionary history of life wikipedia , lookup
Sexual selection wikipedia , lookup
Evidence of common descent wikipedia , lookup
Inclusive fitness wikipedia , lookup
Population genetics wikipedia , lookup
Transcript
Chapter 13 How Populations Evolve Videos As you watch the following videos, take not of different events that occur during each. Once all videos are watched – are there any things that remain consistent throughout all of them? Evolution in 1 minute How did Homer Simpson evolve? Guiness’ idea of evolution Evolution with Emojis Evolution with Emojis Examples of Evolution 1. Write down 5 animals or plants that first come to mind 2. Explain the environment the animal or plant lives in. 3. Explain how each animal or plant is adapted for the environment that it lives in. History of Life on Earth Evolutionary Timeline Theorists that helped contribute to our modern day theory of evolution from Charles Darwin: • Charles Lyell –uniformintarianism (geologic processes still changing Earth) • Thomas Malthus – struggle for existence (resources) • James Hutton - Gradualism • John Baptiste Lamarck – Inheritance of acquired Characteristics and Law of Use and Disuse • Alfred Russel Wallace – organisms evolved from common ancestors Myths and Misconceptions of Evolution Darwin’s Voyage Darwin’s Voyage - 22 yo– traveled on the HMS Beagle from England - 5 year voyage around the world - Collected samples of plants/animals/fossils - much of collections and observations came from the Galapagos islands - wrote his ideas in a book “On the Origin of Species” Galapagos Islands • Group of islands off coast of S. America • Each island has different climates • Animals on each island were unique –Tortoises –Iguanas –Finches • Organisms differ from island to island and from S. America • Artificial selection – humans have modified species by selecting and breeding individuals that possess desired traits (selective breeding) - Natural selection – process of selection in nature observation #1 – members of a population vary in their traits, and most traits are inherited from parent to offspring observation #2 – all species are capable of producing more offspring than the environment can support inference #1 – individuals whose inherited traits give them a higher probability of surviving and reproducing in a given environment tend to leave more offspring than other individuals inference #2 – unequal production of offspring will cause favorable traits to accumulate in a population Natural Selection in Action Natural Selection in Action Natural Selection in Action Before Industrial Revolution During Industrial Revolution What is Evolution? Darwin Summary 1. Struggle for Existence 2. Survival of the Fittest 3. Descent with Modification Struggle for Existence Organisms compete for resources Resources include…. Survival of the Fittest • Fitness – Ability of an Individual To Survive & Reproduce • Adaptation – Inherited Characteristic That Increases an Organisms Chance for Survival – Physical » Speed, Camouflage, Claws, Quills, etc. – Behavioral » Solitary, Herds, Packs, Activity, etc. Descent with Modification • Takes Place Over Long Periods of Time • Natural Selection Can Be Observed As Changes In – Body Structures – Ecological Niches – Habitats Darwin’s Theory of Evolution by Natural Selection 1. All species have genetic variation. 2. Living things struggle to exist. 3. Individuals of species compete with one another to survive. 4. Individuals that are better adapted to their environment leave more offspring than those less adapted. 5. Characteristics of individuals better adapted for their environment increase in a population over time. Strong Evidence of Evolution 1. Fossils – preserved remnant or impression or an organism that lived in the past - found in different sedimentary rock layers called strata - oldest fossils (prokaryotes) = 3.5 BYA Strong Evidence of Evolution 2. Biogeogrpahy - different animals on different continents but similar adaptations to shared environments - animals move to new area and eventually become adapted to their new environment Strong Evidence of Evolution 3. Comparative anatomy - homology – similarity in characteristics that results from common ancestry - homologous structures – structures that have different functions but are structurally similar - vestigial organ – remnants of structures that served important functions in the organisms ancestors but serve no function today - embryology – looking at embryos for similar structures Strong Evidence of Evolution 4. Molecular Biology - all forms of life use the same genetic language of DNA, RNA and genetic code - looking at DNA sequences of organisms - shows how closely related organisms are Example of Evolution Camouflage http://www.youtube.com/watch?v=EJGtNigCu8&safe=active Mimicry http://ngm.nationalgeographic.com/2009/08/mimicry/ mimicry-interactive Macroevolution vs. Microevolution Macroevolution – change on a grand scale; events that create and destroy species Microevolution – a change in a population’s gene pool over time - gene pool = alleles for genes in a population Hardy Weinberg Equilibrium - works when looking at microevolution of populations (group of same organism) Principle stating that the shuffling of genes occurring during sexual reproduction is not the only thing changing the genetic makeup of a population - For a population to be in Hardy Weinberg equilibrium it must satisfy 5 conditions: 1. Very large population 2. No gene migration 3. No mutations 4. Random mating 5. No natural selection Hardy Weinberg Equilibrium Hardy Weinberg Equilibrium The following statements look at wildflower population. After reading each statement, state which conditions the population deviates from. 1. A windstorm blows in hundreds of seeds from a nearby meadow, where nearly all the flowers are yellow. 2. A pollutant molecule from the soil gets in the way just as a developing egg cell in one of the red flowers is replicating its DNA. Quite by chance, the red allele is transformed into a yellow allele. 3. The flowers tend to grow in red and yellow patches. A landslide buries and kills most of the red flowers. Hardy Weinberg Equilibrium 4. The red pigment in the petals of the red flowers is poisonous and protects them from beetles that eat the developing seeds. The yellow flowers are not protected in this way. 5. The bees that pollinate the f lowers tend to develop a “search image.” Once they start visiting flowers of a certain color, they stick to that color. So pollen from red flowers is more likely to be delivered to other red flowers, and pollen from yellow flowers is more likely to fertilize other yellow flowers. Evolutionary Tree • Hypotheses reflecting current understanding of patterns of evolutionary descent Alterations in Allele Frequencies 1. Genetic drift – change in the gene pool of a population due to chance tends to reduce genetic variation Bottleneck effect – drastic reduction in population size and change in allele frequencies - Due to earthquakes,floods, fires, etc. Founder effect – when a few individuals become isolated from a larger population Alterations in Allele Frequencies 2. Natural selection 3. Gene Flow – when a population may gain/lose alleles when fertile individuals move into/out of a population or when gametes are transferred between populations Natural Selection on Polygenic Traits 1. Stabilizing selection – favors intermediate phenotypes 2. Directional selection – acts against a phenotype at one extreme 3. Disruptive selection – favors individuals at both phenotypic extremes Sexual Selection - natural selection in which individuals with certain characteristics are more likely than other individuals to obtain mates - Sexual dimorphism – differences in males/females in secondary sex characteristics Sexual Selection • Intrasexual selection (w/i same sex) – in some species, secondary sex structures may be used to compete with members of the same sex for mates. – Physical combat, ritualized displays • Intersexual selection/mate choice – individuals of one sex are choosy in selecting their mates – Females choose males based on traits Chapter 14 The Origin of Species • Speciation – emergence of a new species – Bridge between microevolution and macroevolution – Taxonomy classifies and names these organisms – Barriers keep species separate Reproductive Barriers – keep species separate 1. Prezygotic Barriers – prevent mating or fertilization a. temporal isolation – mating occurs at different seasons/times of day b. habitat isolation – populations live in different habitats and do not meet Reproductive Barriers – keep species separate c. behavioral isolation – little/no sexual attraction between different species d. mechanical isolation – structural differences between organisms do not allow them to mate e. gametic isolation – male/female gametes die before uniting or fail to unite Reproductive Barriers – keep species separate 2. Postzygotic barriers – prevent the development of fertile adults a. reduced hybrid viability – hybrids fail to develop or to reach sexual maturity b. reduced hybrid fertility – hybrids fail to produce functional gametes c. hybrid breakdown – offspring of hybrids are weak/infertile Types of Speciation 1. Allopatric speciation – geographic barrier isolates a population and causes new species 2. Sympatric speciation – formation of new species of organisms in the same geographic area a.accidents during cell division (new species called polyploid) Speciation occurs rapidly or slowly • Punctuated equilibrium – long periods of little change • Graduated equilibrium – long period with small changes Adaptive Radiation - Evolution of diverse species from a common ancestor - Occurs when a few organisms colonize a new area or when environmental changes cause extinctions and provide opportunities for survivors Evolutionary Relationships Look at the diagram above and answer the following: 1. What does this diagram depict? 2. Where does the information come to depict a diagram like this? 3. Which organisms are closely related? Which are not closely related? Give an example for each. 4. Which organism is the most recently evolved? Which organism is the oldest, evolutionarily speaking?