Students may need help here, even if they have learned evolution and natural selection. Here`s a way to help: Second, Elliot writes as if common ancestry is the only reasonable explanation for neutral or harmful similarities. I agree, but there were a number of competing explanations for this phenomenon at the time the origin was written (like Owen`s archetype). A world saturated with neutral and harmful similarities may be our idea of the epistemological paradise with regard to the hypothesis of common ancestry, but I wonder what mid-19th century biologists would have derived from such a world. An important question that Elliot`s project seems to answer is whether the probability of common ancestry was raised as an explanation of neutral or harmful similarities (compared to that of other available explanations) when natural selection was assumed to be the cause of adaptation. And if so, why? As Elliot points out after the original quote, Darwin seems to have thought so. The human population on Earth is thought to have had a slow start, with doubling periods of up to 1 million years. It is estimated that the current world population doubles every 37 years. How would this growth rate compare to the rates found in your research? 3.So a lot for my main suggestion on E on D on NS. Next: E on D on CA. Here I`m not sure how different I am from E.So sharpening the problems, let me point out how big the gap between us could be. The E-articulation of what he calls the Darwin principle (DP) is, in my opinion, to focus on the properties of Useles.
Of course, as he shows, D cited such properties as evidence for CA. But much more often, D`s argument was not about properties as such, but about similarities or other similarities. Why do all placental mammals have in common an absence (until humans bring some there) from Australia when they can thrive there when taken by humans? We cannot explain this frequent absence because it is due to a common adaptation to conditions that can only be found outside of Australia and therefore not in this area, as it is enough to look at how much they were transported there. A joint declaration of adaptation for this frequent absence is therefore not sufficient. But one explanation for CA is good: the placental mammal species all descend from a CA that lived outside of Australia, and no offspring were able to enter kangaroo land without human help. I agree with Elliott Sober that common ancestry can be tested independently of knowledge of natural selection. In fact, I think the best evidence of common ancestry has nothing to do with natural selection, and I think Darwin did too (see chapter 13 of The Origin, where he talks about classification). However, this does not mean that the theory of natural selection is manifestly unrelated to common ancestry. Natural selection provides a mechanism of change that is necessary if there is to be a deviation from the common ancestor. It is easier to find common ancestors that are more plausible in the case of Chapter 1 pigeons than in the case of plants and animals, precisely because we can more easily imagine how populations might undergo a small change, as opposed to a big change.
This is not just a psychological bias; That is a good scientific argument. Sober says nothing else in his essay, but he focuses on whether natural selection is necessary to prove common ancestry and ignores whether it can provide evidence. Providing a mechanism that can supposedly lead to arbitrarily large amounts of change, as Darwin thought natural selection might (although I would argue that this is the case), makes it much more plausible that very different morphological groups have a common ancestry. In fact, the theory of natural selection lowers the bar of the amount of evidence needed for specific arguments in favor of common ancestry. Looking at the origin of the species, it is quite conceivable that a naturalist who thinks of the mutual affinities of organic beings, their embryological relationships, their geographical distribution, geological succession and other similar facts could conclude that each species was not created independently, but descended as varieties of other species. Nevertheless, such a conclusion, even if it is well-founded, would not be satisfactory until it can be shown how the countless species that inhabit this world have been modified to achieve that perfection of structure and co-adaptation that rightly arouses our admiration. You should point out to students the general question of what is at the bottom of the cube. Tell students that they must answer the question by suggesting an explanation and that they must convince you and other students that their answer is based on evidence.
(Evidence refers to observations the group can make on the visible sides of the cube.) Give students time to explore the cube and develop answers to their question. Here are some factual observations or statements students can make: This activity extends the general idea of population growth to humans. This is the important point that man lives in the ecosystems of the world. Humans are increasingly altering ecosystems due to population growth, technology and consumption. The destruction of human habitat through direct harvesting, pollution, atmospheric change and other factors threatens current global stability and, if left unaddressed, ecosystems will be irreversibly affected. Choose fabric patterns that simulate natural environments, for example. B floral, floral, leaf or fruit prints. Patterns must have several colors and be of complex design; Small prints work better than large block prints. Select two themes, each with a different predominant color. Label one fabric design A and fabric B.
The use of two models allows students to demonstrate the evolution of different types of colors from the same initial population. The insecticide is effective only under certain environmental conditions – for example, certain temperatures and humidity levels – that have changed during work. But Darwin can only address relevance where he does, because in previous chapters he addressed the more fundamental question of existence. And he does so, as Elliott suggests, without anticipating a common ancestry. The argument is based on an analogy with artificial selection. The Malthusian struggle for existence is a cumulative selector of variation in a manner similar to how Darwin suggests that the breeder is on the farm. But since malthusian struggle is so much more powerful, its impact will be comparatively greater – leading to new species rather than mere varieties. Ask students to use their observations (the data) to suggest an answer to the question: What`s at the bottom of the cube? Student groups should be able to make a statement, such as: We come to the conclusion that there is a 2 at the bottom.
Students should explain the reasons for this conclusion. For example, they could base their conclusion on the observation that the exposed sides are 1, 3, 4, 5 and 6, and because 2 is missing from the sequence, they conclude that it is on the merits. TO STUDENTS: A farmer was working in an agricultural experimental station with dairy cattle. The population of flies in the barn where the cattle lived was so large that the health of the animals was affected. So the farmer sprayed the barn and cattle with a solution of insecticide A. The insecticide killed almost all flies. Engage Initiate a discussion about the human population with questions such as: How long have people been on Earth? How do you see the early rate of human population growth compared to today`s population growth rate? Why has this rate changed? Due to the variety of data sources (information), this cube can be difficult for students. .