BIOLOGY NOTES EVOLUTION PART 1 PAGES 297-319

Standards: 6.1 ____Explain how the scientific theory of evolution is supported by the fossil record, comparative anatomy, comparative embryology, biogeography, molecular biology, and observed evolutionary change ____ Describe the conditions required for natural selection, including: overpopulation of offspring, inherited variation, and the struggle to survive, which results in differential reproductive success ____ Describe how mutation and genetic recombination increases genetic variation ____ Explain how and why the genetic code is universal and is common to almost all organisms 6.2 6.3 6.12

Essential Questions: What mechanisms have allowed for 1. 2. diversity in organisms? 1. 2. How is the scientific theory of evolution supported by different disciplines?

Evolution = the biological process of _______ by which ____________ come to differ from their __________ change descendents ancestors

A. History 1. Carolus Linnaeus (1700’s) – proposed that organisms are not _____ but do change over time from breeding experiments species = a group of __________ so similar to one another they can reproduce and have ______ offspring fixed organisms fertile

2. Georges Louis Leclerc de Buffon (1700’s) – proposes that species _______ ancestors instead of arising separately shared

3. James Hutton (1795) & Charles Lyell (1833) – two geologists who discovered that the Earth was really ________, not thousands, of years old Hutton and Lyell broke former ________ by studying rock layers and suggesting geographical formations due to weather, ________, and other natural forces occur slowly. Thus, the Earth must be ________ of years old. millions theories erosion millions

4. Thomas Malthus (1798) – An economist who suggested that human population growth is _______ by resources such as food, water and space. A population that grew too large would result in a ________ for existence. This led evolutionists to wonder if ________ also competed as animals generally have even more offspring than humans limited struggle animals

5. Jean Baptiste Lamarck (1809) – A scientist who proposed the theory of _________ characteristics Lamarck believed that an organism’s ____ or disuse of a trait determined if it were passed on to _________ e.g. acquired use offspring fiddler crab claw, birds flying

This is an obviously ________ hypotheses because an organism’s ________ cannot affect it’s heredity Lamarck’s hypotheses were important, however, because he is the first scientist to suggest that organisms do, in fact, _______ over time and are ultimately adapted to their ____________ incorrect behavior change environment

6. Alfred Wallace (1858) – A scientist whose studies in _________ confirms Darwin’s theory of _________ Malaysia evolution

5. Charles Darwin – proposed the modern scientific theory of _________ through the MECHANISM of _______ selection Studied different fossils, collected evidence, and made numerous observations while on board the _____________ in 1831 got most of his evidence from the __________ islands Published the ______ of Species in 1859 with his mechanism (how it happens) of evolution evolution natural H.M.S. Beagle Galapagos Origin

B. Darwin’s Modern Theory of Evolution Premise #1: Individuals differ and these differences are _________ (passed on to offspring) At this point in time Mendel’s work was not very well known so Darwin did not know ____ variation among organisms occurred inherited how

Darwin, however, did know variation occurred among ________ species by observing and recording variation among _________ of organisms e.g. with Mendel’s work, we now know this variation occurs at the genetic level and we call the variations for a single trait _______ different hundreds finches, tortises, etc. alleles

with a better understanding of genetics we now know variation occurs because of ___________ and during _______ reproduction / _________ over mutations sexual crossing

Premise #2: Organisms _________ for limited resources. Struggle for existence = members of the same ________ regularly compete for _____, living space, etc. compete species food

Members of the same species compete because of ______________ overpopulation

Fitness = the ability of an individual to _______ and reproduce in its environment each organism has advantages or disadvantages in the struggle for _______ adaptation = any inherited _____________ that increases an organism’s chances of ________ survive survival characteristic survival

If the environment changes, something that may have been an _____________ could or could not be of use e.g. adaptation dinosaur size

Premise #3: Within each species competition, there are winners and ______ Natural Selection (a.k.a.) Survival of the fittest = those organisms best ________ to their environment survive to reproduce and these organisms pass on their traits (acts on ___________) Evolution occurs through _______ selection (also known as the MECHANISM of evolution) losers adapted phenotypes natural

Conclusion #1: Those species of organisms that are alive today are ____________ from a common ________ but, have been _________ or changed over time (EVOLUTION) As natural selection occurs, species gradually become very ________ from each other this is what Darwin termed ________ with ____________ descendent ancestor modified different descent modification

C. Evidence for the Scientific Theory of Evolution 1 C. Evidence for the Scientific Theory of Evolution 1. Fossils = preserved remains or _________ of the existence of an organism e.g. evidence dino bones

This tells us that there have been a _______ of different organisms alive over millions of _____ The lower in the rock layers, the _____ the organism is believed to be Within millions of years there are large _____ WHY? ______________ variety years older gaps decomposition

most fossils are found in ____________ rock b. other types of fossils include: ______, amber preserved fossils, petrified fossils, imprints, and ______ sedimentary casts molds

c. as ____________ continues, many missing “links” have been ___________ paleontology discovered

2. Homologous Body Structures = structures that have different ________ but the same basic _________ e.g. Similar structures indicate similar genetic codes in the _____ molecules of an organism Remember the genetic code is _________ and millions or even billions of base pairs long in every cell function structure bat wings, human hand, whale flipper DNA universal

It is unlikely that long sequences of matching base pairs exist in two ________ species unless these organisms evolved from a _________ ancestor this can be proven using genetic ___________ different common sequencing

Why would organisms have organs they do not use? 3. Vestigial Organs = organs present within an organism that serves no useful ________ e.g. Why would organisms have organs they do not use? if the organs do not affect the survival of ____, then natural selection would not have eliminated these organs this can also explain why there are ________ pieces of DNA found in almost all _____________ function human appendix life unused organisms

The presence, however, of vestigial organs suggests that several different _______ could have evolved from a single ________ species ancestor

4. Embryology Many organisms look similar in structure as ________ which indicates they have a common _________ e.g. Why do organisms eventually look extremely different from embryo to full grown individual? ________________ embryos ancestor rat, human, chicken cell differentiation

Larva Adult barnacle Adult crab

5. Molecular & Genetic Evidence = it has been shown that very different ________ have similar molecular and ________ mechanisms the more related two organisms are, the more _______ their DNA will be species genetic related

pseudogenes = sequences of _____ nucleotides that are no longer _______ having similar _____________ reflects a common _________ 6. Biogeography - Geographical ____________ of common plants & animals e.g. 7. Observed Evolutionary Change DNA useful pseudogenes ancestor distribution Whale bones in African desert Spread of antibiotic resistant bacteria