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9 February Define these words: Evolution Microevolution (you may use your phone) Macroevolution (you may use your phone) Can you answer this question? What did we learn about genetics in relation to alleles, genes, polygenetic inheritance, and phenotype? The Program for International Student Assessment (65 countries surveyed 15 year-old students) USA is 30th in mathematics 23rd in science 20th in reading The U.S. was slotted between the Slovak Republic and Lithuania in the overall results, two spots behind Russia. Huffington post reports that A 2009 study found that U.S. students ranked 25th among 34 countries in math and science, Tongue Rolling Widow's Peak Chin fissure Attached earlobes KEY CONCEPT There were theories of biological and geologic change before Darwin. Charles Darwin Born: February 12, 1809 Died: April 19, 1882 Published the Origin of Species in 1859 Studied plant hormones, breeding variation in pigeons and many other things. Alfred Russel Wallace (8 Jan. 1823 – 7 Nov 1913) Wallace was a British naturalist, explorer, geographer, anthropologist, and biologist. He is best known for independently conceiving the theory of evolution through natural selection; his paper on the subject was jointly published with some of Charles Darwin's writings in 1858. This prompted Darwin to publish his own ideas in On the Origin of Species. Wallace did extensive fieldwork, first in the Amazon River basin and then in the Malay Archipelago, where he identified the faunal divide now termed the Wallace Line, which separates the Indonesian archipelago into two distinct parts: a western portion in which the animals are largely of Asian origin, and an eastern portion where the fauna reflect Australasia. He was considered the 19th century's leading expert on the geographical distribution of animal species and is sometimes called the "father of biogeography". Wallace was one of the leading evolutionary thinkers of the 19th century and made many other contributions to the development of evolutionary theory besides being codiscoverer of natural selection. These included the concept of warning colouration in animals, and the Wallace effect, a hypothesis on how natural selection could contribute to speciation by encouraging the development of barriers against hybridisation. http://en.wikipedia.org/wiki/Alfred_Russel_Wallace Early scientists proposed ideas about evolution. • Evolution is the biological change process by which descendants come to differ from their ancestors. • A species is a group of organisms that can reproduce and have fertile offspring. Evidences of Evolution • There were many important naturalists in the 18th century. – Linnaeus: classification system from kingdom to species – Buffon: species shared ancestors rather than arising separately – E. Darwin: more-complex forms developed from less-complex forms – Lamarck: environmental change leads to use or disuse of a structure Theories of geologic change set the stage for Darwin’s theory. • There were three theories of geologic change. – catastrophism – uniformitarianism – gradualism • Uniformitarianism – processes that change the earth are uniform through time. • Gradualism – proposed by James Hutton. Change in landforms happen in small stages over very long periods of time. Do pages: 99 and 100 in your Study Guide. 10 February How can you tell if microevolution has taken place? What do you remember from yesterday? Without opening your book, work with your neighbor and make a list of at least four ways microevolution has taken place Define these words – components of Darwin’s theory of Natural Selection: - Define and Give examples of each – Variation Non-random mating Embryology Homologous structures Fossils Biogeography Vestigial structure Natural Selection Darwin’s voyage provided insight on evolution. In red are the four pillars of Natural Selection Darwin observed differences among island species. • Variation is a difference in a physical trait. – Galápagos tortoises that live in areas with tall plants have long necks and legs. – Galápagos finches that live in areas with hard-shelled nuts have strong beaks. • An adaptations is a feature that allow an organism to better survive in its environment. – Species are able to adapt to their environment. – Adaptations can lead to genetic change in a population. Spore cloud All species are capable of producing more offspring (overproduction) than the environment can support Descent with Modification • Darwin never used the word evolution in the first edition of The Origin of Species • The phrase descent with modification refers to the view that all organisms are related through descent from an ancestor that lived in the remote past … the unity of life • In the Darwinian view, the history of life is like a tree with branches representing life’s diversity • Darwin’s theory meshed well with the hierarchy of Linnaeus The following are Evidences of Evolution Darwin observed fossil and geologic evidence supporting an ancient Earth. • Darwin found fossils of extinct animals that resemble modern animals. • Darwin found fossil shells high up in the Andes mountains. • He saw land move from underwater to above sea level due to an earthquake. • Darwin extended his observations to the evolution of organisms. Evidence for evolution in Darwin’s time came from several sources. • Fossils provide evidence of evolution. • Fossils in older layers are more primitive than those in the upper layers. Fossils provide a record of evolution. • Paleontology is the study of fossils or extinct organisms. • Paleontology provides evidence to support evolution. Molecular and genetic evidence support fossil and anatomical evidence. • Two closely-related organisms will have similar DNA sequences. • Hox genes indicate a very distant common ancestor. – control the development of specific structures – found in many organisms • Protein comparisons, or molecular fingerprinting reveals similarities among cell types of different organisms. Evolution unites all fields of biology. • Scientist from any fields contribute to the understanding of evolution. • The basic principles of evolution are used in many scientific fields. The study of geographic distribution provides evidence of evolution. – island species most closely resemble nearest mainland species – populations can show variation from one island to another • Embryology provides evidence of evolution. – identical larvae, different adult body forms – similar embryos, diverse organisms Larva Adult crab Adult barnacle • 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. Human hand Mole foot Bat wing 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. • Ostrich wings are examples of vestigial structures. 11 February Phenotypic change over time is driven by changes in the environment. Those organisms that survive will pass on their traits to their offspring, thus influencing future generations. To make these predictions we can use the Hardy-Weinberg equation p2 + 2pq + q2 = 1 You have sampled a population in which you know that the percentage of the homozygous recessive genotype (aa) is 36%. Using that 36%, calculate the following: 1) The frequency of the "aa" genotype. 2) The frequency of the "a" allele. 3) The frequency of the "A" allele. 4) The frequencies of the genotypes "AA". 5) The frequencies of the genotypes “Aa” You have sampled a population in which you know that the percentage of the homozygous recessive genotype (aa) is 36%. Using that 36%, calculate the following: 1) The frequency of the "aa" genotype. Answer: 36%, as given in the problem itself. 2) The frequency of the "a" allele. Answer: The frequency of aa is 36%, which means that q2 = 0.36, by definition. If q2 = 0.36, then q = 0.6, again by definition. Since q equals the frequency of the a allele, then the frequency is 60%. 3) The frequency of the "A" allele. Answer: Since q = 0.6, and p + q = 1, then p = 0.4; the frequency of A is by definition equal to p, so the answer is 40%. 4) The frequencies of the genotypes "AA"." Answer: The frequency of AA is equal to p2, So, using the information above, the frequency of AA is 16% (i.e. p2 is 0.4 x 0.4 = 0.16). 5) The frequencies of the genotypes “Aa”. The frequency of Aa is equal to 2pq. Aa is 48% (2pq = 2 x 0.4 x 0.6 = 0.48). • Genetic variation leads to phenotypic variation. • Phenotypic variation is necessary for natural selection. • Genetic variation is stored in a population’s gene pool. – made up of all alleles in a population – allele combinations form when organisms have offspring • Allele frequencies measure genetic variation. – measures how common allele is in population – can be calculated for each allele in gene pool Genetic variation in a population increases the chance that some individuals will survive. Where is that variation contained? Within a population of butterflies, the color brown (B) is dominant over the color white (b). And, 40% of all butterflies are white. Given this simple information, which is something that is very likely to be on an exam, calculate the following: The percentage of butterflies in the population that are heterozygous. The frequency of homozygous dominant individuals. The first thing you'll need to do is obtain p and q. Since white is recessive (bb), and 40% of the butterflies are white, then bb = q2 = 0.4. To determine q, take the square root of q2which works out to be 0.63 q = 0.63. Since p + q = 1, then p must be 1 - 0.63 = 0.37. Now then, to answer our questions. First, what is the percentage of butterflies in the population that are heterozygous? 2pq represents (Bb), so the answer is 2 (0.37) (0.63) = 0.47. 47% Second, what is the frequency of homozygous dominant individuals? That would be p2 or (0.37)2 = 0.14. 12 February Lab 10 Fill out the allele worksheet by interviewing 12 other people. Calculate the genotypes (AA, Aa, aa) for four of the traits on the board using the HardyWeinberg equation, you must show your work. Turn in when completed. Use the Hardy-Weinberg equation to calculate four (4) frequencies for all three genotypes p2 + 2pq + q2 = 1 and p + q = 1 Tongue Rolling Widow's Peak - just like Eddie Munster roll/not roll yes/no L/R interlocking finger - without thinking, clasp your hands together, is L/R or R/L the right thumb over the left, or vice versa? Attached earlobes - ask a neighbor or check out the mirror yes/no Hitchhiker Thumb - does it bend back at a 90 angle yes/no Chin fissure - like actor Michael Douglas yes/no Darwin tubercle - little bump on the inside of the ear yes/no Pigmented iris - any color but blue yes/no Freckles yes/no Dimples yes/no Curley hair yes/no Long eyelashes (> 1cm) yes/no Is this a dominant or recessive phenotype based on class data? Genotype A trait is an abstraction (hair color, eye color, etc.) while the phenotypes are the observable differences of a given trait. Phenotype A trait is eye color, a phenotype is having blue eyes. TT, Tt Or tt 17 February Define: Speciation – Convergent evolution – Coevolution – Variation – Analogous structure – Common ancestor – Hominid – Youtube – Bill Nye Evolution https://www.youtube.com/watch?v=1xIi4RQiZW4 Concepts to look for in the video Origin of self-replicating molecules Evidences of evolution (fossils, homology, molecular, biogeography, embryology) 19 February Additional Evidences of Evolution. Define these words and use examples to increase your comprehension: • Geographic isolation • Behavioral isolation • Genetic drift • Bottleneck effect • Gene flow • Adaptive radiation Next (maybe tomorrow) I will ask you how these concepts are related to natural selection. 20 February Do Study Guide Questions Pages 101 – 108 All questions Videos on natural selection, Darwin & Wallace and the diversity of finches in the Galapagos Islands 24 February • • • • • • Geographic isolation Behavioral isolation Genetic drift Bottleneck effect Gene flow Adaptive radiation Geographic isolation Harris’ Antelope Squirrel Ammospermophilus harrisii White-tailed Antelope Squirrel Ammospermophilus leucurus Behavioral isolation Blue footed booby Sula nebouxii https://www.youtube.com/watch?v=4MPfTzXEZdY Genetic Drift • The smaller a sample, the greater the chance of deviation from a predicted result • Genetic drift describes how allele frequencies fluctuate unpredictably from one generation to the next • Genetic drift tends to reduce genetic variation through losses of alleles Effects of Genetic Drift: A Summary 1. Genetic drift is significant in small populations 2. Genetic drift causes allele frequencies to change at random 3. Genetic drift can lead to a loss of genetic variation within populations 4. Genetic drift can cause harmful alleles to become fixed Figure 23.12 60 Survival rate (%) 50 Population in which the surviving females eventually bred Central Eastern Central population NORTH SEA Eastern population Vlieland, the Netherlands 40 2 km 30 20 10 0 Females born in central population Females born in eastern population Parus major Genetic drift • Gene flow can increase the fitness of a population • Consider, for example, the spread of alleles for resistance to insecticides – Insecticides have been used to target mosquitoes that carry West Nile virus and malaria – Alleles have evolved in some populations that confer insecticide resistance to these mosquitoes – The flow of insecticide resistance alleles into a population can cause an increase in fitness Gene flow is the movement of alleles between populations • Gene flow: movement of alleles from one pop. to another • Occurs when individuals join new populations and reproduce. • Gene flow keeps neighboring populations similar. • Low gene flow increases the chance that two populations will evolve into different species. bald eagle migration Adaptive Radiation • Adaptive radiations: closely related species that have recently evolved from a common ancestor by adapting to different parts of the environment • Occurs – in an environment with few other species and many resources – Hawaiian and Galápagos Islands – Catastrophic event leading to extinction of other species Adaptive radiation The Nature of Species • Speciation: the process by which new species arise, either by – transformation of one species into another (phyletic speciation), – or by the splitting of one ancestral species into two descendant species 25 February Finish Natural Selection packet 26 February Lab Exercise Natural Selection – Evolution Game: Where only the fit win Objective – develop a game using the principals of natural selection & evolution. Your group must develop the ‘rules’ and how the game will be run. Your grade will be comprised of two parts. a) Fully developed rules and a logical explanation of how the game would be played. Those groups that complete this will earn up to 10 points. b) The group that develops the best game will receive 10 extra credit points. 1) Develop groups 2) The rules and procedures you develop must include the concepts of “Genetic Drift”, “Gene Flow” and “Mutations”. 3) Other concepts that you can incorporate into your game are: Bottleneck effect, adaptive radiation, behavioral isolation, geological isolation, micro and/or macroevolution, and vestigial structures. 4) You will present your game to the class. Natural selection acts on distributions of traits. • A normal distribution graphs as a bell-shaped curve. – highest frequency near mean value – frequencies decrease toward each extreme value • Traits not undergoing natural selection have a normal distribution. • Natural selection can take one of three paths. – Directional selection favors phenotypes at one extreme. • Natural selection can take one of three paths. – Stabilizing selection favors the intermediate phenotype. • There are two types of sexual selection. – intrasexual selection: competition among males – intersexual selection: males display certain traits to females • Reproductive isolation can occur between isolated populations. – members of different populations cannot mate successfully – final step to becoming separate species • Speciation is the rise of two or more species from one existing species. Speciation often occurs in patterns. • A pattern of punctuated equilibrium exists in the fossil record. – theory proposed by Eldredge and Gould in 1972 – episodes of speciation occur suddenly in geologic time – followed by long periods of little evolutionary change – revised Darwin’s idea that species arose through gradual transformations • Many species evolve from one species during adaptive radiation. – ancestral species diversifies into many descendent species – descendent species usually adapted to wide range of environments Chapter 12.3 Earth was very different billions of years ago. • There have been many hypotheses of Earth’s origins. • The most widely accepted hypothesis of Earth’s origins is the nebula hypothesis. Several sets of hypotheses propose how life began on Earth. • There are two organic molecule hypotheses. – Miller-Urey experiment: demonstrated that organic molecules could be made by passing an electric current, simulating lightning, through closed system that held a mixture of gases electrodes “atmosphere” water “ocean” heat source amino acids Organic compounds could be made by passing an electrical current through a mixture of gasses (methane, ammonia, hydrogen and water vapor). • These atmospheric gasses comprise the carbon and nitrogen necessary for amino acids to be formed. • The oceans provided the elements of oxygen and hydrogen. • Meteorite hypothesis: amino acids may have arrived on Earth through meteorite or asteroid impacts • There are different hypotheses of early cell structure. – iron-sulfide bubbles hypothesis: biological molecules combined in compartments of chimney-like structures on the ocean floor. The compartments acted as the first cell membranes. • There are different hypotheses of early cell structure. – lipid membrane hypothesis: lipid spheres, or liposomes, could form around a variety of organic molecules, acting as a cell membrane • A hypothesis proposes that RNA was the first genetic material. – Ribozymes are RNA molecules that catalyze their own replication. – DNA needs enzymes to replicate itself. Eukaryotic cells may have evolved through endosymbiosis. • Endosymbiosis is a relationship in which one organism lives within the body of another. • Mitochondria and chloroplasts may have developed through endosymbiosis. KEY CONCEPT 12.6 Humans appeared late in Earth’s history. Humans share a common ancestor with other primates. • Primates are mammals with flexible hands and feet, forward-looking eyes and enlarged brains. • Primates evolved into prosimians and anthropoids. – Prosimians are the oldest living primates. – They are mostly small and nocturnal. – Anthropoids are humanlike primates. – They are subdivided into the New World monkeys, Old World monkeys, and hominoids. – Homonoids are divided into hominids, great apes, and lesser apes. – Hominids include living and extinct humans. • Bipedal means walking on two legs. – foraging – carrying infants and food – using tools • Walking upright has important adaptive advantages. There are many fossils of extinct hominids. • Most hominids are either the genus Australopithecus or Homo. • Australopithecines were a successful genus. • The Homo genus first evolved 2.4 million years ago. Modern humans arose about 200,000 years ago. • Homo sapiens fossils date to 200,000 years ago. • Human evolution is influenced by a tool-based culture. • There is a trend toward increased brain size in hominids. Australopithecus afarensis Lucy – 4 mybp Homo habilis Homo neanderthalensis 1.5 mybp Homo sapiens 196,000 thousand ybp 7 February 2014 Chapter 17.2 Define these words: Phylogeny – Cladistics – Cladogram – Derived characters – KEY CONCEPT 17.2 Modern classification is based on evolutionary relationships. Cladistics is classification based on common ancestry. • Phylogeny is the evolutionary history for a group of species. – shown with branching tree diagrams (cladograms) – Cladograms constructed by id’ing derived characters – evidence from living species, fossil record, and molecular data • Cladistics is a common method to make evolutionary trees. – classification based on common ancestry – species placed in order that they descended from common ancestor • A cladogram is an evolutionary tree made using cladistics. – A clade is a group of species that shares a common ancestor. – Each species in a clade shares some traits with the ancestor. – Each species in a clade has traits that have changed. • Derived characters are traits shared in different degrees by clade members. Useful for determining evolutionary relationships between species. – basis of arranging species in cladogram – more closely related species share more derived characters – represented on cladogram as hash marks 1 Tetrapoda clade 2 Amniota clade 3 Reptilia clade 4 Diapsida clade 5 Archosauria clade FEATHERS & TOOTHLESS BEAKS. SKULL OPENINGS IN FRONT OF THE EYE & IN THE JAW OPENING IN THE SIDE OF THE SKULL SKULL OPENINGS BEHIND THE EYE EMBRYO PROTECTED BY AMNIOTIC FLUID FOUR LIMBS WITH DIGITS DERIVED CHARACTER • Nodes represent the most recent common ancestor of a clade. CLADE 1 Tetrapoda clade 2 Amniota clade 3 Reptilia clade 4 Diapsida clade 5 Archosauria clade FEATHERS AND TOOTHLESS BEAKS. • Clades can be identified by snipping a branch under a node. SKULL OPENINGS IN FRONT OF THE EYE AND IN THE JAW OPENING IN THE SIDE OF THE SKULL SKULL OPENINGS BEHIND THE EYE EMBRYO PROTECTED BY AMNIOTIC FLUID NODE FOUR LIMBS WITH DIGITS DERIVED CHARACTER Molecular evidence reveals species’ relatedness. • Molecular data may confirm classification based on physical similarities. • Molecular data may lead scientists to propose a new classification. • DNA is usually given the last word by scientists. 10 February 2014 Chapter 17.4 1) Which two species are most closely related? A B 2) Which of the following would be used to determine the evolutionary relationships of these organisms? C a) b) c) d) E DNA sequences Analogous structures Homologous structures Similarity of ecological niches D 11 February 2014 Chapter 17.4 What does the word Kingdom mean, in relation to living things? What about Domains? 1) Which two species are most closely related? 2) Which of the following would be used to determine the evolutionary relationships of these organisms? a) b) c) d) DNA sequences Analogous structures Homologous structures Similarity of ecological niches A B C D E KEY CONCEPT 17.3 Molecular clocks provide clues to evolutionary history. Molecular clocks use mutations to estimate evolutionary time. • Mutations add up at a constant rate in related species. – This rate is the ticking of the molecular clock. – As more time passes, there will be more mutations. • Scientists estimate mutation rates by linking molecular data and real time. – an event known to separate species – the first appearance of a species in fossil record Mitochondrial DNA and ribosomal RNA provide two types of molecular clocks. KEY CONCEPT 17.4 The current tree of life has three domains. Classification is always a work in progress. • The tree of life shows our most current understanding. • New discoveries can lead to changes in classification. – Until 1866: only two kingdoms, Animalia and Plantae Animalia Plantae Classification is always a work in progress. • The tree of life shows our most current understanding. • New discoveries can lead to changes in classification. – Until 1866: only two kingdoms, Animalia and Plantae Animalia – 1866: all single-celled organisms moved to kingdom Protista Plantae Protista Classification is always a work in progress. • The tree of life shows our most current understanding. • New discoveries can lead to changes in classification. – Until 1866: only two kingdoms, Animalia and Plantae Animalia – 1866: all single-celled organisms moved to kingdom Protista Plantae Protista – 1938: prokaryotes moved to kingdom Monera Monera Classification is always a work in progress. • The tree of life shows our most current understanding. • New discoveries can lead to changes in classification. – Until 1866: only two kingdoms, Animalia and Plantae Animalia – 1866: all single-celled organisms moved to kingdom Protista Plantae Protista – 1938: prokaryotes moved to kingdom Monera – 1959: fungi moved to own kingdom Monera Fungi Classification is always a work in progress. • The tree of life shows our most current understanding. • New discoveries can lead to changes in classification. – Until 1866: only two kingdoms, Animalia and Plantae Animalia – 1866: all single-celled organisms moved to kingdom Protista Plantae Protista – 1938: prokaryotes moved to kingdom Monera – 1959: fungi moved to own kingdom Archea Fungi Bacteria – 1977: kingdom Monera split into kingdoms Bacteria and Archaea The three domains in the tree of life are Bacteria, Archaea, and Eukarya. • Domains are above the kingdom level. – Carl Woese: studied rRNA of prokaryotes and found they were two separate groups, genetically speaking – domain model more clearly shows prokaryotic diversity • Domain Bacteria includes prokaryotes in the kingdom Bacteria. – one of largest groups on Earth – classified by shape, need for oxygen, and diseases caused • Domain Archaea includes prokaryotes in the kingdom Archaea. – cell walls chemically different from bacteria – differences discovered by studying RNA – known for living in extreme environments • Bacteria and archaea can be difficult to classify. – transfer genes among themselves outside of reproduction bridge to transfer DNA – blurs the line between “species” – more research needed to understand prokaryotes • Domain Eukarya includes all eukaryotes. – kingdom Protista • Domain Eukarya includes all eukaryotes. – kingdom Protista – kingdom Plantae • Domain Eukarya includes all eukaryotes. – kingdom Protista – kingdom Plantae – kingdom Fungi • Domain Eukarya includes all eukaryotes. – – – – kingdom Protista kingdom Plantae kingdom Fungi kingdom Animalia KEY CONCEPT 17.1 Organisms can be classified based on physical similarities. Linnaeus developed the scientific naming system still used today. • Taxonomy is the science of naming and classifying organisms. White oak: Quercus alba • A taxon is a group of organisms in a classification system. • Binomial nomenclature is a two-part scientific naming system. – uses Latin words – scientific names always written in italics – two parts are the genus name and species descriptor • A genus includes one or more physically similar species. – Species in the same genus are thought to be closely related. – Genus name is always capitalized and italisized. • A species descriptor is the second part of a scientific name. – always lowercase – always follows genus name; never written alone Tyto alba • Advantages: unique name for each species, scientists around the world recognize them – Some species have very similar common names. – Some species have many common names. Linnaeus’ classification system has seven levels, called taxa. • Each level is included in the level above it. • Levels get increasingly specific from kingdom to species. The Linnaean classification system has limitations. • Linnaeus taxonomy doesn’t account for molecular evidence. – The technology didnt exist during Linneaus’ time. – Linnaean system based only on physical similarities. • Physical similarities are not always the result of close relationships. • Genetic similarities more accurately show evolutionary relationships. Geographic isolation Variation Punctuated equilibrium Kingdom Protista Phylogeny Archaea Behavioral isolation Kingdom Fungi Homologous structures Convergent evolution Vestigal structure Gene flow Bottleneck effect Reproductive isolation Kingdom Animalia Cladogram Endosymbiosis Geographic isolation Adaptive radiation Intersexual Genetic Drift Anthropoids Embryology Natural Selection Intrasexual Eukarya Biogeography Bacteria Fossils Coevolution Cladistics Evolution Kingdom Plantae Hominid Speciation Prosimians Primate