* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Evidence for Evolution
Survey
Document related concepts
Unilineal evolution wikipedia , lookup
Sexual selection wikipedia , lookup
The Descent of Man, and Selection in Relation to Sex wikipedia , lookup
Population genetics wikipedia , lookup
Natural selection wikipedia , lookup
Precambrian body plans wikipedia , lookup
Inclusive fitness wikipedia , lookup
Evidence of common descent wikipedia , lookup
Theistic evolution wikipedia , lookup
Hologenome theory of evolution wikipedia , lookup
Genetics and the Origin of Species wikipedia , lookup
Koinophilia wikipedia , lookup
Transcript
Domain 5 Evolution 15% 1 Focus Standards SB5. Students will evaluate the role of natural selection in the development of the theory of evolution. a. Trace the history of the theory. b. Explain the history of life in terms of biodiversity, ancestry, and the rates of evolution. c. Explain how fossil and biochemical evidence support the theory. d. Relate natural selection to changes in organisms. e. Recognize the role of evolution to biological resistance (pesticide and antibiotic resistance 2 EVOLUTION Evolution is the theory that organisms change over time, a process by which modern organisms have descended from ancient organisms. History behind the theory • Proposed by Charles Darwin (Darwinism) and Alfred Wallace in 1858 • Earlier concepts of evolution – Carolus Linnaeus (a Swedish botanist who laid the foundations for the modern scheme of nomenclature). – Georges Louis Leclerc de Button- challenged many of the accepted ideas of the day. Proposed that species shared ancestors instead of rising separately. – Eramus Darwin- Darwin’s grandfather. Proposed that all living things were descended from a common ancestor and that more complex 4 forms of life arose from less complex forms. Earlier concepts on evolution cont. • Jean-Baptiste Lamarck (Lamarckism)-Proposed that by selective use or disuse of organs, organisms acquired or lost certain traits during their lifetime. This is known as the Inheritance of acquired traits • Thomas Malthus (economist)- Reasoned that if the human population continued to go unchecked, sooner or later there would be insufficient living food and space for everyone. • George Cuvier- Proposed the theory of catastrophism that natural disasters such as floods and volcanic eruptions have happened often during Earth’s long history. • These events shaped landforms and caused species to become extinct in the process Earlier concepts of evolution cont. • James Hutton (geologist)- Proposed that changes he observed in landforms resulted from slow changes over a long period of time, known as gradualism. – Argued that the laying down of soil or the creation of canyons by rivers cutting through rock were not the result of large events, rather slow processes that happened in the past. • Charles Lyell (geologist)- Expanded Hutton’s theory of gradualism into the theory of uniformitarianism. Proposes that the geologic process that shapes Earth are uniform through time. – Observed processes that made small changes in Earth. Darwin’s Observations Great diversity among species Animals were well adapted to habitat Different species live in similar ecosystems Animals on the Galapagos islands varied according to where they lived Tortoises Finches GENETIC VARIATION • Evolution is caused by genetic variation. • Genetic variation comes from changes in DNA, which can be caused by: –Crossing over (occurs during Prophase I of meiosis I) –The random assortment of genes (during meiosis II) –Mutations (in genes and chromosomes) –Artificial selection –Natural selection ARTIFICIAL SELECTION • Artificial selection takes place with human control or direction. • Examples of artificial selection –Selective breeding –Genetic engineering EXAMPLE OF ARTIFICIAL SELECTION • Broccoli, cabbage, kale, cauliflower, and kohlrabi are common vegetables that were cultivated from forms of wild mustard. • This is evolution through artificial selection. NATURAL SELECTION Natural selection is the process by which organisms that are best suited to live in an environment survive, passing on their genetic traits to their offspring. NATURAL SELECTION • Natural selection takes place without human control or direction. • Over time, natural selection results in changes in the characteristics of the population. Natural Selection vs. Artificial Selection • Artificial Selection- The process by which humans change a species by breeding it for certain traits. – Humans determine which traits are favorable and breed individuals that show those traits. • Natural Selection- The mechanism by which individuals that have inherited beneficial adaptations produce more offspring than do other individuals. – The environment is the selective agent, therefore, characteristics are selected only if they give advantages to individuals in the environment as it is right now. Lamarck vs. Darwin Introduction to change in organisms 16 What is a theory? • The most probable explanation for a large set of data based on the best available evidence • Summarizes a hypothesis or group of hypotheses that have been supported with repeated testing What is a species? What is a population? • Species – group of a single type of organisms that interbreed and are reproductively isolated • White-tailed deer • Population – refers to a group of organisms of a particular species living in a certain area. • White-tailed deer on Mt. Nebo Lamarck’s Theory • Jean Baptiste Lamarck: 1800’s – Believed: • Change Occurs Over Time • inheritance of acquired characteristics – acquired changes were passed to offspring • Law of Use and Disuse – If a body part were used, it got stronger – If body part NOT used, it deteriorated • Examples: Body builders or pierced ears Lamarck’s Theory of Evolution • Giraffes all had SHORT necks originally • Giraffe’s Necks got LONGER from stretching for food • “Acquired” trait (long necks) then passed to offspring • Giraffe population became long-necked Lamarck’s Theory of Evolution • More examples – Traits Acquired During Ones Lifetime Would Be Passed To Offspring Clipped ears and tails of dogs could be passed to offspring! Lamarck’s Mistakes • Was he correct?? – NO! • Traits are passed down from one generation to the next by GENES, not by an individual’s life experiences or activities • Lamarck did NOT know how traits were inherited (Traits are passed through genes) • Genes Are NOT Changed By Activities In Life • Change Through Mutation Occurs Before An Organism Is Born Voyage of the Beagle Charles Darwin • Born Feb. 12, 1809 • Joined Crew of HMS Beagle, 1831 • Naturalist • 5 Year Voyage around world • Astounded By Variety of Life Voyage of the Beagle During His Travels, Darwin Made Numerous Observations And Collected Evidence That Led Him To Propose A Revolutionary Hypothesis About The Way Life Changes Over Time Darwin’s Belief’s • Survival of the fittest OR natural selection – Food and resources are limited • So organisms have to COMPETE to get them (lions fight for food, space, mates …) • OVER PRODUCE too many organisms • Not all offspring will survive only the MOST FIT (not always the strongest!) What happened to the giraffe’s? – Survival of the fittest or natural selection • Natural selection said the giraffes with short necks had less food to eat • Why? – the food resources changed to leaves only on the upper branches • What happened? – short necks could not reach upper branches and did not survive (couldn’t pass on genes) – Long neck giraffes survived & reproduced because they were able to reach the food • Evolution is the slow, gradual change in a population of organisms over time… a looooooooong time! • When there is an unequal ability of individuals to survive and reproduce … • This leads to a gradual change in a population with favorable characteristics accumulating over generations • Most fit “naturally” selected • New species evolves Natural Selection • How does Selection occur? – Selection of the most fit can occur from several factors: • Variations exist among individuals in a population • Competition for limited resources • Overpopulation • Predation/Disease Example of Natural Selection • A classic example of natural selection is the Peppered moths during Industrial Revolution in Europe THE HISTORY OF LIFE FOSSILS • Fossils are the mineralized remains of animals or plants or other artifacts such as footprints. • The totality of fossils and their placement in rock formations and sedimentary layers (strata) is known as the fossil record. • The fossil record provides evidence about the history of life on Earth. It also shows how different groups of organisms have changed over time. • The fossil record reveals that fossils occur in a particular order: some only in older rock and some only in more recent rock. • The study of fossils is called paleontology. DATING FOSSILS • Relative dating allows paleontologists to estimate a fossil’s age compared with that of other fossils. • In radioactive dating, scientists calculate the age of a sample based on the amount of remaining radioactive isotopes it contains. • Scientists use the half-life of radioactive isotopes to date fossils. Evidence for Evolution 37 Evidence Evidence of common ancestry among species comes from many sources. 38 #1 Fossil Evidence Fossils o Earth is Millions of years old! o Fossils in older layers are more primitive than those in the upper layers. o Extinct Fossils resemble modern animals. o This shows a common ancestry. 39 Types of Fossils Permineralization occurs when minerals carried by water are deposited around a hard structure A natural cast forms when flowing water removes all of the original tissue, leaving an impression. 40 Types of Fossils Amber-preserved fossils are organisms that become trapped in tree resin that hardens after the tree is buried. Fossilized insects 41 Types of Fossils Impressions are imprints left in rock Preserved remains form when an entire organism becomes encased in material such as ice, ash, tar … 42 Dating Fossils 43 Relative Dating of Fossils Estimates the time during which an organism lived It compares the placement of fossils in layers of rock Scientists infer the order in which species existed 44 Radiometric Dating of Fossils Measures the half-life of the isotope – the time it takes for ½ of the isotope to break down Carbon-12 stable; Carbon-14 radioactive (carbon in ALL organisms) Example: – Carbon-14 has a half-life of 5730 years; decays into Carbon-12 – Compare ratio of C-14 to C-12 to age fossil 45 Radiometric Dating of Fossils Uses Radioactive Isotopes: atoms of the same element with differing neutrons Example: – – – 12C and 14C 12C = 6 protons + 6 neutrons 14C = 6 protons + 8 neutrons 46 Radiometric Dating of Fossils 47 #2 Geographical Distribution Geography & environment gives evidence for evolution Island species most closely resemble nearest mainland species Populations can show variation from one island to another 48 #3 Embryology Embryo (early developmental stage) gives evidence of evolution Identical larvae, different adult body forms Similar embryos, related but diverse organisms Shows common Larva ancestry Adult crab Adult barnacle 49 #3 Embryology Vertebrates all share gill slits and a tail in their early embryo stage; Share a common ancestor 50 #4 Comparative Anatomy The study of anatomy provides evidence of evolution Homologous structures are similar in structure but different in function. Homologous structures ARE EVIDENCE of a common ancestor. 51 Homologous Structures ARM LEG Flipper Wing 52 #4 Comparative Anatomy Analogous structures are similar in function but differ in structure Analogous structures DO NOT show common ancestry Fly wing Bat wing 53 Structural patterns are clues to the history of a species. Vestigial structures are remnants of organs or structures that had a function in an early ancestor. Examples include ostrich wings, human appendix, and wisdom teeth, whale and snake pelvis/hind legs 54 Pythons have tiny femurs (leg bone) 55 #5 Molecular and Genetic Evidence AKA Biochemical Evidence Two closely-related organisms will have similar DNA, RNA, and protein (amino acid) sequences. This also gives evidence of a common ancestor. 56 57 Five examples of Evidence for Evolution 1.Fossils 2.Geographical Distribution 3.Embryology 4.Comparative Anatomy 5.Molecular and Genetic 58 Destruction of Natural Enemies Development of Resistance 62