* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Answers to Questions for 16,17 and 19
Survey
Document related concepts
Hologenome theory of evolution wikipedia , lookup
Natural selection wikipedia , lookup
Theistic evolution wikipedia , lookup
Organisms at high altitude wikipedia , lookup
Punctuated equilibrium wikipedia , lookup
Evidence of common descent wikipedia , lookup
Genetic drift wikipedia , lookup
Transitional fossil wikipedia , lookup
Paleontology wikipedia , lookup
Inclusive fitness wikipedia , lookup
Saltation (biology) wikipedia , lookup
The eclipse of Darwinism wikipedia , lookup
Evolutionary history of life wikipedia , lookup
Transcript
16.1 Answers: 1. * A scientific theory of evolution * explains how modern organisms change over time through decent from common ancestor 2. a) species vary globally • many locations where animals were similar but not the same • animals in some locations but not in others (ex. rabbits, kangaroo) b) species vary locally • related but different animal species occupy different habitats in a local area (ex: Galapagos tortoises on different islands) c) species vary over time • he collected fossils and noticed that some fossils were similar to living specimens 16.2 Answers: 3. The earth is very old. Earth is still changing its surfaces. • Lyell’s book helped Darwin understand the significance of geological change (ex: earthquake) and how over many years, a mountain range could be made, etc. (rocks under the sea could be pushed to surface, etc.) *Darwin asked himself: “If earth can change so much over time, could living things do the same?” 4. Lamarck was a naturalist. He said: 1. used body parts would get bigger, unused parts would shrink **Darwin wanted to know WHY fewer organisms 3. organisms have a desire to change survive than are created. 5. Lamarck was NOT correct. He wanted to know WHY some survived and some 6. Malthus said that if human population continued to grow with more births than deaths, food and space would soon did not…ie; what was the REASON run out and disease, famine, war will result to limit 2. acquired characteristics are inherited population. 16.2 Answers Continued 7. Nature provides the variation (thru mutations) and humans SELECT those traits which are useful. ex: breeding animals and plants only with the desired characteristics (think selective breeding from last unit) ** Darwin recognized that variations were the raw materials needed for evolution to occur 16.3 Answers (#8) Struggle for Existence: * after reading Malthus’ work, Darwin realized that if there is limited food and space for a population, that set up a natural competition and struggle for those resources Variation and Adaptation: * Darwin knew individuals varied. Some variations may be better suited to win in the competition for resources. This was an advantage. “adaptation”= any inheritable characteristic which increases one’s ability to survive and reproduce in an environment. Survival of the Fittest: * a connection between how an organism “makes a living” and the environment it is in. * differences in rates of survival/reproduction = survival of fittest. “fitness”= how well one can survive and reproduce in a given environment 16.3 Answers cont’d 9. Natural Selection: organisms with best variations to survive the given environment will survive better, longer, and reproduce. Now, those best fit genes will be passed on. Fig protective coloration of green variety allows more of them to survive and reproduce. After time, there are more green than brown in the population 10. Natural Selection is NOT: * geared to make one “perfect” * purposeful * moving in one direction Natural Selection IS: • a process of making one good enough to survive a given environment and pass genes to next generation ** IF the environment changes, a new selection process may begin and a new phenotype may be better fit to survive. ex: What if in Fig 16-10, there was a severe drought one summer. What may happen? 16.3 Answers cont’d 11. Natural Selection depends on descendants to leave genes for the next generation. Well adapted species survive over time. * Darwin said that over time, one species may change enough to evolve into another * also said that living species have descended (with changes) from a common ancestral species * evidence of this is present in the fossil record. * from this he drew the first “evolutionary Tree” * all species- living and extinct- are descended from ancient common ancestors. * The “Tree of Life” links all living things 16.4 Answers 12. Biogeography- looking at patterns in the distribution of living things. Where things live now and where their ancestors lived in the past ** these patterns in fossils and living specimens tell us how modern species may have evolved from their ancestors a) closely related but different: * on Galapagos, biogeography suggested that island species evolved from mainland species. *Natural selection over time maintained those best adapted to that particular island environment. * compared to mainland specimens, the island ones were closely related but different b) distantly related but similar: * animals and plant in similar environments globally may have similar adaptations due to similar environmental pressures. *BUT: these animals and plants are not closely related *ex: ground-dwelling birds in Europe, Australia, Asia look different, but have developed similar adaptations to survive in a similar environment separately 16.4 Answers cont’d 13. * fossils discovered after Darwin fill in some of the “gaps” in the evolution/fossil record. * one fossil shows the evolution of whales from a land-based mammal. 14. Homologous structures: similar in design, different in function. ex: bird wing, human arm, frog front leg * shows evolutionary relationship due to similar bone pattern and genetic info to make it the same way 15. Analagous structures have same function but different design. ex: bird wing and insect wing. do not support common decent 16.4 Answers cont’d 16.Traces of homologous structures in other species. ex: hip bone in dolphin are vestiges of it’s ancestor’s pelvic bone ex: third eye lid, appendix, tail bone *genetically and evolutionarily links all animals who make whole or part of that structure 17. Similar patterns in embryonic development is evidence of decent from common ancestor ex: human, pig, frog, fish early embryos are all very similar (tail and gill slits (pharyngeal pouches)) 18. * Genetic Code for translation of DNA is universal * All life uses ATP as energy molecule * All life has it’s instructions in DNA molecule * common proteins like cytochrome c in all living things 17.1 Answers 1. Evolution: a genotype determines a phenotype. This phenotype may be an advantage to the survival of that organism. * evolution is the CHANGE in the frequency of alleles in the gene pool of a population over time 2. Gene pool = all the genes (alleles) of a species 3. relative (allele) frequency = how often the allele is present in the gene pool – it does not matter if the allele is dominant or recessive. 4. CHANGE in the frequency of alleles in the gene pool of a population over time add: ** Natural Selection operates on INDIVIDUALS, but the changes in allele frequencies show up at the POPULATION level. Q: in a total of 50 alleles, 20 are B (black) and 30 are b (brown). How many of each allele would be present in a total of 100 alleles? Q: What is the relative frequency of the dominant allele (B) and the recessive allele (b)? Q: If the relative frequency of B allele changes to 30%, the population is evolving (changing) 17.1 Answers cont’d 5. 3 sources of genetic variation: a) mutation: at level of gene or chromosome * may or may not affect fitness of individual * must be made in germ cells to affect offspring b) genetic recombination in sexual reproduction: * alignment of tetrads (metaphase) produces 8.4 million gene combinations per gamete! * crossing over prior to this makes countless more variations per gamete! c) lateral gene transfer: DNA transfer to non-offspring * bacterial plasmid swapping 6. Depends on how many genes control a trait 7. Single: a trait controlled by ONE gene, 2 or 3 phenotypes possible ex: banding in snail shells * phenotypic ratios determined by frequency of alleles AND if they are dominant or recessive (banded shell is recessive) 17.1 Answers cont’d and 17.2 Answers 8. Polygenic trait: controlled by 2+ genes, each with 2+ alleles. Therefore: many phenotypes result. ex: human height 9. Bell-curves show distribution of a polygenic trait 17.2 Answers: 10. Natural selection on single-gene traits can lead to allele frequency changes and therefore phenotype changes. ex: mutation causes red and black body color in lizard * red more visible…eaten quicker * black absorb more sun, get warmer faster, more energy to avoid predator… 17.2 Answers cont’d 11. Effects of natural selection on polygenic traits is more complex: • in bell curve distribution, fitness can vary from one end of curve to another. • when fitness varies, natural selection can act. • can produce 3 types of selection: a) directional: when those at ONE end of curve have higher fitness than those at middle or other end. ex: large beaks needed to eat large seeds b) stabilizing: when those at CENTER of curve have better fitness than those at either end ex: avg. birth weight in babies c) disruptive: when those at EITHER end of curve have better fitness than those at middle ex: if medium size seeds become less common 17.2 Answers cont’d 12. Genetic Drift: when an allele becomes more or less common by CHANCE (not nat’l sel.) and allele frequencies show a dramatic change * in small populations, individuals left after a major event don’t represent original gene pool. * a. bottleneck effect – after a natural disaster (disease, flood, fire, famine), the few survivors don’t represent the original gene pool - reduces genetic variability * b. founder effect: when a few individuals colonize a new area. - evolution of flies on Hawaii. Species on different islands have allele frequencies that are different from original species on mainland 17.2 Answers cont’d 15. 13. Genetic equilibrium = when allele frequencies in a population remain the same….no evolution is taking place p = dominant allele frequency 14. HW Principle: allele frequencies in a population remain constant UNLESS one or more factors cause frequencies to change. p+q=1 5 conditions to maintain allele frequencies: p2 + 2pq + q2 = 1 q = recessive allele frequency HW formula: 1. large population p2 = % of population pure dominant 2. no mutations 2pq = % population hybrid dominant 3. random mating q2 = pure recessive 4. no migration in or out if p=.4 and q=.6, what % of the population would be: 5. no natural selection 16- 17. when these happen: small population, mutations, particular mating, migration, and natural selection happen, evolution occurs a) pure dom______ b) hybrid dom______ c) pure recessive______ 17.3 Answers 18. Species: a population whose members can interbreed and produce fertile offspring mixed species hybrids Speciation: the formation of new species 19. Reproductive Isolation: allows for members of one species to develop into two different ones once reproduction is no longer happening. 20. Can happen in these ways: a) behavioral isolation: when courtship rituals differ b) geographical isolation: when geographical barriers prevent reproduction (river, mountain, ocean) c) temporal isolation: when reproduction occurs at different times of year or day, etc. 17.3 Answers cont’d 1 4 21. Five steps to the 14 finch species on the Galapagos Islands: 1) founders arrive 2) geographic isolation 3) changes in gene pools 5 2 4) behavioral isolation 5) competition and continued evolution 3 19.1 Answers 1. What do fossils reveal about ancient life? Fossils tell us the structure of ancient organisms, their environment and the ways in which they lived. 2. What types of fossils exist? Can be a whole organism, teeth, bones, leaf pieces, droppings 3. What is relative dating? Describe how it works. Relative dating: using the layers of sedimentary rock, we can determine if a fossil is older or younger than other fossils. Useful, but does not give us an actual age in years. 19.1 Answers cont’d 4. What is radiometric dating? How is it done? Radiometric dating: uses the proportion of radioactive to stable isotopes to determine age of fossil. * use the known rate of decay of an isotope: the “half life” * half-life = the amount of time for 50% of the radioactivity to decay * half-life of 14C is 5730 years. * in 5730 yrs, 50% remains (1/2) * in ANOTHER 5730 yrs, 25% remains (1/4) * in ANOTHER 5730 years, 12.5% remains (1/8) • What isotopes are used for recent fossils and very old fossils? recent fossils: 14C older fossils: 40K or 238U 5. What time did humans appear? 11:58:56 pm 19.2 Answers 6. What is a “clad”? What processes influence whether species/clades will survive? Clad = a group of species which includes a single common ancestor and all descendants of that ancestor * if rate of speciation is same as or greater than rate of extinction, then clad will survive * if extinction rate is greater than speciation rate, clad will not survive. 7. What is the benefit of a mass extinction? Benefit was the increase in diversity and speciation of those who survived 19.2 Answers cont’d 8. Describe and explain the differences between punctuated equilibrium and gradualism. Rate of evolution is thought to be different for different species at different times in history. Two methods: 1. gradualism: slow and steady change over time 2. punctuated equilibrium: long periods of little or no change interrupted by periods of great change and rapid evolution 9. Why does evolution happen faster in smaller populations? Give an example.Smaller populations evolve faster because genetic changes spread more quickly and are seen more rapidly in a small group. 10. Describe the process that is adaptive radiation. Adaptive radiation: process where a single species evolves in short time into several different forms who live in different ways. After dinos extinction, mammals showed a huge adaptive radiation and diversification *Galapagos finches show modern adaptive radiation 19.2 Answers cont’d 11. Look at (Fig. 19-11). Which mammal group is most closely related to the elephants?The Sirenians (Manatee) 12. After the dinosaurs disappeared, what happened with the evolution of mammals? Why was this? Mammals diversified very quickly. Had more space, food, some predators were extinct now. 13. Name 3 ways in which adaptive radiation may occur. a) when species move to a new environment b) when extinction clears an area of a number of organisms c) development of a new feature which makes a previously unusable environment now accessible 14. What is convergent evolution? How does it happen? Explain Fig. 19-12 with this concept. Convergent evolution: similar environments select for similar features in organisms not related through common descent. • All anteaters have similar mouth structure due to convergent evol. • emus, ostrich, rheas all similar looking, but not related 19.2 Answers cont’d 15. What is “co-evolution” and how does it happen? Give examples with flowers and plants. Co-evolution:the relationship between 2 evolving organisms is so specific that one can’t survive with out the other. A change in one will bring about a change in the other • Ex: flowers and pollinators. Some flower structures require one or a select few types of insects to access nectar. • (ex: 40-cm long tongue of a moth to reach nectar inside orchids on Galapagos) • Ex: plants evolved bad tasting poisons so insects won’t eat them 16. Once plants developed toxins to keep insects from eating them, what happened? Natural selection chose for those insects who could tolerate or use the toxin. **Monarch gets a free defense weapon and no Why will ONLY Monarch caterpillars feed on the milkweed plant? Why does this exclusivity benefit competition from other insects for the same food. BOTH the milkweed and the Monarch? Monarch caterpillars can tolerate toxin AND store it to use as Milkweed plant only eaten by one type of insect a defense from predators! 19.3 Answers 17. How did earth originate? Pieces of cosmic debris crashing into each other 18. Describe the early atmosphere. Early atmosphere had only CO2,H2O vapor, and N2. NO O2 Oceans contained high amount of iron. 19. Miller/Urey: Simulated the early atmospheric gases energy sources. Amino acids were produced in the “ocean” water flask. and 20. First genetic material: RNA. Simpler as a single strand, some RNA’s can help DNA replication, some can modify mRNA pieces, some act as enzymes, some can replicate on own. 21.Why were first life forms anaerobic? No O2 in early atmosphere 22. Early photo bacteria released oxygen, made rusty colored oceans. Great bands of iron are still mined on the ocean floor today 19.3 Answers 23. What is the Endosymbiont theory? What evidence supports this theory? The explanation of how eukaryotic cells evolved from prokaryotic ones. * infolding of cell membrane nuclear envelope and ER, golgi * engulphment of smaller bacteria mitochondria and chloroplasts * evidence: mitochondria and chloroplasts have their own DNA and can replicate on their own 24. Why is sexual reproduction so vital to the evolutionary process? Sexual reproduction increases genetic variations that drives evolution