Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Name: answers Evolutionary Processes Workbook 5 Year 13 Science 2016 Patterns of evolution The fossil record demonstrates macroevolution as structural changes in hard body parts are seen. The fossil record shows transitional forms in whale evolution. To show relationships taxonomists arrange organisms into phylogenetic trees based on their primitive and more specialised structural characteristics. 1. What does the original walking front limb evolve into? Flipper Recently DNA evidence has become important. Rate of Change – gradualism and punctuated equilibrium In species selection, the species that survive the longest in evolutionary history: produce most new species have the greatest effect on a pattern If environmental conditions change, the trend may reverse or stop - as macroevolution takes place, new groups of species arise, change and become extinct over time. Evolution proceeds by gradualism, punctuated equilibrium, or a combination of both. In gradualism, there is a slow, constant rate of change in species over time in response to various selection pressures – as shown by transitional forms in the fossil record. In punctuated equilibrium, there may be very long periods of stasis, perhaps brought about by stabilising selection, where there is hardly any evolutionary change for millions of years, followed by short burst of rapid speciation. This often involved the formation of many different species that are no longer closely related. There are few transitional fossils because of the rapid pace of change. 2. Which evolutionary tree shows slow, continual change? gradualism 3. Which evolutionary tree shows periods of rapid change? punctuated equilibrium 4. Name the pattern of evolution for each of the following situations. a. The tiny foraminiferan plankton Globotalia, found in New Zealand waters, had a compressed shell and a keel 7 million years ago. The plankton microfossil record shows the many tiny changes towards the modern form, which has a rounded shell with no keel. gradualism b. gradualism c. A punctuated B gradualism d. d. punctuated 5. a. b. c. d. Write a definition for each of the key words in the table - in your own words Keyword gradualism punctuated equilibrium phylogenetic tree stasis Definition slow, constant rate of change in species over time in response to various selection pressures very long periods of stasis, followed by short burst of rapid speciation branching diagram that shows evolutionary change hardly any evolutionary change for a long time 6. Does the evolutionary tree shown support a model of gradualism or a model of punctuated equilibrium? Explain your answer. Model of punctuated equilibrium Periods of no change and then periods of change Divergent and Convergent Evolution Divergent evolution is the diversification of a single common ancestral species into two or more species. In convergent evolution, species have different ancestral starting points, but they evolve similar adaptations because they occupy similar ecological niches. Parallel evolution occurs when species that share a common ancestor but are not closely related evolve in a similar way independently of each other. Adaptive radiation is a burst of divergent evolution in which a number of related species diverge from a common ancestor to fill a variety of different ecological niches, often in different geographical areas. An ecological niche is the role that members of a species fill within their biological community e.g. nocturnal carnivorous birds, Each new species in adaptive radiation occupies its own niche, separated from the other species by reproductive isolating mechanisms. 7. a. b. c. d. e. Write a definition for each of the key words in the table - in your own words Keyword divergent evolution convergent evolution parallel evolution adaptive radiation ecological niche Definition diversification of a single common ancestral species into two or more species. species have different ancestral starting points, but they evolve similar adaptations because they occupy similar ecological niches species that share a common ancestor but are not closely related evolve in a similar way independently of each other burst of divergent evolution in which a number of related species diverge from a common ancestor t the role that members of a species fill within their biological community 8. What happens in the period of stasis? there is no change 9. What event demonstrates adaptive radiation? species 2 changes into 3 and 4 10. Is there any demonstration of convergent evolution? no 11. Is there any demonstration of divergent evolution? yes 12. Name the pattern of evolution for each of the following situations. a. At least 10 moa species evolved from a single moa ancestor, which lived about 30 mya. Some moa were very small (29 kg) and others were much larger (250 kg). They occupied habitats from the coast to alpine areas. divergent evolution b. Organs that have the same function because of similar selections pressures, but have different structures are analogous organs e.g. wings of insects and birds. They do not have a common ancestor but have the same function. convergent evolution c. Homologous organs have similar origin and structure e.g. wings on reptiles, bats, birds – similar bone structure and evolved from a common ancestor. divergent evolution d. Hebes are endemic New Zealand plants growing from the coast to high alpine environments. They have evolved from a low-growing ancestral population that arrived from the northern hemisphere. There are now more than 120 species that live in distinct habitats. Leaves are larger where conditions are mild, and smaller in cold dry conditions. There were two bursts of adaptive radiation. divergent evolution 13. There is debate over whether over whether ratites (a group of flightless birds) lost their ability to fly, or could never fly. One idea is that ratites shared a common flightless ancestor. They then dispersed and evolved in geographic isolation, so that modern ratites (emu, kiwi, ostrich) are all very different from one another. However, a researcher in America has suggested each species became unable to fly after evolving from ancestors that could fly. a. What pattern of evolution would ratites show if they had developed over a long time from a common flightless ancestral species? divergent evolution b. What evolutionary pattern is suggested if ratite species each evolved from an ancestor that could fly? parallel 14. Seabirds such as albatross, mollymawk, titi and petrel make up at least half the native bird species in New Zealand. The diagram opposite shows the relationship between five main groups of albatross. a. Name the evolutionary pattern illustrated in the albatross group. divergent evolution b. One major characteristic of the albatross group is the amount of time they spend out at sea, - are many hundreds of different sea birds alive today. i. Suggest a factor that could have produced different ecological niches in the marine environment. different ecological niches occur because of physical factors – sea temperature, storms, and the way the birds have adapted to the biological factors – food supply, predators ii. Suggest a factor that could have prevented gene flow, allowing speciation to occur in the albatross. gene flow may be prevented because breeding usually occurs on land – different mating and breeding places may be geographically isolated (islands) enabling populations to evolve allopatrically - also times of breeding may be different (temporal) 15. Early taxonomists classified the riroriro (New Zealand grey warbler) into the same family as warblers in the Northern Hemisphere, because of similarities in their beak shape and feeding behaviour. After DNA analysis, the New Zealand grey warbler has been reclassified into a genetically unrelated group,. a. Give the term that describes two genetically unrelated groups that over time evolve similar adaptations. convergent evolution b. Give a reason why the New Zealand grey warbler and the Northern Hemisphere warbler, although genetically unrelated, have evolved similar adaptation for feeding. similar evolutionary pressures / same natural selection – similar requirements for food, type of food, and other niche requirements both forms had structurally similar forms to begin with 16. New Zealand’s bird species became adapted to a range of habitats. The curved-beak wren (now extinct) had a long curved beak adapted to extracting grubs from crevices in tree trunks. Other bird species, such as the wood creepers in South America and some tree creepers in Australia, have similar beaks to the curved-beaked wren, they also feed by probing cracks in tree trunks. Explain how these unrelated species could have evolved their physical similarities. these birds have unrelated ancestors but have evolved similar adaptations because they occupy similar niches – this is called convergent evolution birds have evolved to resemble each other each bird feeds by extracting grubs from cracks in tree trunks – each has evolved a long curved beak suited for this method of feeding – beak adapted to this niche 17. Beside each of the following, write whether the structures are homologous or analogous. a. bird wing and human arm homologous b. lungs of mammals and trachea (air tubes) of insects analogous c. bat wing and butterfly wing analogous d. fantail’s eye and cow’s eye homologous 18. Write either true or false alongside each of the following statements. If the statement is false, write the statement correctly. a. The wing of a bee is homologous to the wing of a finch. analogous b. Convergent evolution can result in ecological equivalents. true c. Punctuated equilibrium is a theory than can account for the lack of transitional forms in the fossil record. true d. Species undergoing convergent evolution occupy similar ecological niches. true e. Worldwide, areas with similar climates have similar plant communities, but the plants are from very different taxa (phylogenetic groups). The similarities result from parallel evolution. convergent 19. The two species of Howea palm on Lord Howe Island evolved there from a common ancestor between one and two million years ago. Scientists have found that the two Howea species grow in the same area. a. Identify the pattern of evolution that could give rise to these two palm species. divergent evolution b. Identify the type of speciation that is most likely to have occurred in Howea palms. sympatric speciation - does not involve geographic barrier c. Palms are wind pollinated flowering plants. Explain how wind pollination could be related to the two Howea species being reproductively isolated. could release pollen at different times , so pollen from one species would not be available to pollinate the other – temporal isolation 20. Seals and penguins both have flippers and streamlined bodies for swimming. Name and describe the pattern of evolution that this shows, and using the examples above, explain how this type of evolution can occur. pattern of evolution is convergent seals and penguins are not closely related but have evolved to live in the same environment so are subject to similar selection pressures these pressures have resulted in both species evolving steamlined bodies which facilitate movement through the water flippers – from forelimbs in seals flippers – from wings in penguins both types of flippers are analogous structures needed to move the body through the water Co-evolution is reciprocal evolutionary change – a change in the trait of one species acts as a selection pressure for a change in a trait of another unrelated species. Example: An evolutionary change in the structure of a plant might act as a selection pressure to bring about a change in a herbivore that eats the plant. This change in the herbivore then acts as a selection pressure for a change in the structure in the plant to reduce herbivory. Co-evolution is more likely when different species interact with one another. predator and prey parasite and host species that compete for food, shelter, nesting sites species that have a mutualistic (symbiotic) relationship pollinators and flowering plants 21. Snapdragon plants have evolved flowers whose shape and colour make them attractive to bumblebees. The bees have evolved sense organs and mouthparts that enable them to find and extract pollen from snapdragon flowers. Suggest how the snapdragon and bumblebee might have evolved. both may be the product of co-evolution snapdragon plant developed flowers that were visited by bumblebees – this resulted in pollination and produced more plants with similar flowers those bumblebees with mouthparts and sense organs best suited for extracting pollen from snapdragons were selected for in areas where bumblebees and snapdragons were both present if a change in snapdragon flowers occurred, there would be strong selection pressures for bumblebees to change 22. Leapard seals are a predator of Antartic species of penguin. It is possible that these seals and penguins may have co-evolved. Explain how co-evolution may have occurred in this example. leopard seals are predators of penguins – any feature of the seal that improves its success as a predator makes it more likely to survive and breed and pass on successful alleles greater predatory success of the seals acts as selection pressure on penguins – penguins that reduce the predatory success of seals are more likely to survive and pass on their successful alleles onto their offspring – these alleles will increase in frequency in the gene pool these changes act as selection pressures on the seals – and so on – penguins and seals are coevolving