Lamarck believed in something different then Darwin. He believed that animals could sense a need and "passed" it on to their kids. Lamarck believed life had began through spontaneous generation. He claimed new primitive life forms sprained up throughout the history of life. Lamarck proposed that organisms were driven from simple to increasingly more complex forms. The proposing life took on its current form through matural process. Darwin relied on almost the same evidence for evolution (vestigial structures and artificial selection through breeding) but he made different arguements. Another early evolutionary phisospher is Georges Cuvier. He founded vertebrate paleontology as a scientific discipline and created comparitive method of organismal biology. He established the fact of the extinction of past landforms. Thomas Malthus was another early evolutionary philosopher who is widely known for his theories about change in population. He said that sooner or later the population will be checked by famine and disease, leading to what is known as a Malthusian catastrophe. He thought that the dangers of population growth precluded progress towards a utopian society. Thomas had said a decrease in population will cause a large amount of substince to grow and when there is less substince, a decrease of population will take place.
Animals and insects do many things or change in many ways to be able to survive. The first thing I m going to talk about is mutation. Mutation is a change of the nucleotide sequence of the genome of an organism, virus or extrachromosomal genetic element. Mutations may or may not produce discernible changes in the observable characterists of an organism. For example, at a period in time we may see an decrease of green coloration genes in a beetle population. It is possible that some"green genes" mutated to "brown genes." This is an exaqmple of mutation.
Migration also causes a change in an organism. For example, some beetles with brown genes immigrated from one population to another or some beetles carrying the green genes just emigrated. This causes two different colors or types of organisms to breed and produce a new color or new kind of organism.
Genetic drift causes a change in a population also. Genetic drift is the change in the frequency of a gene variant in a population due to random sampling.The alleles in the offspring are a sample of those in the parents, and chance has a role in determining weather a given individual survives and reproduces. Genetic drift may cause gene variants to disappear completely and thereby produce genetic variation. For example, when beetles reproduced there were more brown genes than green genes in the offspring. Brown genes occur slightly more frequent in the offspring than in the parents generation.
Natural selection is also another way organisms change. Natural selection is the gradual process by ewhich biological traits becomne either more or less common in a population as a function of the effect of inherited traits on the differential reproductive sucess of organisms interacting with their environment. This term was popularized by Charles Darwin. Throughout the individuals' lives, their genomes interact with their environments to cause variations in traits. Individuals with certain variants of the trait may survive and reproduce more than individuals with other vairants. Animals that are pretty may attract the opposit sex more but also at the same time they may stand out which makes it easier for predators to see them and kill them. An animal may escape predation more than another because they blend in and reproduce more, which causes that color of animal to reproduce more.
There are evidence for evolution in a lot of organisms to this day. DNA is an example of evolution. There are animals that are similar to those back in the day. The only explanation of this is DNA being passed down through generations. Serial structures are usually identical in the embryo, but specialized and diverged in the adult. Different species in the same class often have very similar embryos, even if the adult forms are quite deifferent. Variations in adult features are inherited at corresponding late stages. Darwin extrapolated this to larger groups, for example, the forelimbds might be legs in an ancestral species, but would be modified as flippers, arms, wings, etc at late stage in development; but the pattern in the embryonic stage would remain similar if not unchanged. Also the fossil record shows us evidence for evolution. Fossils are like snapshots of the past. Some fossils may missing pieces but we still can get a good look at an animal in the past. By comparing fossils to the bones in the present day, we can see how things have changed over time. We can see how animals from different locations adapted by looking at fossils. Comparative anatomy is also evidence of evolution. Buffon and Lamarck used comparative anatomy to determine relationships between species. There are common things foun in different species that show us they may be closely related. For example, bats, birds, and insects all have wings but we need to be careful when evalutating species this way. The wings of bats and birds are both derived from the forelimb of a common, probably wingless, ancestor. A difficulty in comparing traits between species rests on the fact that homologous structures not present in the adult organism often do sppear in some stage of embryonic development. For example, a humans embryo passes through a stage in which it has gill structures like a fish, and a tail like our close primat relatives. There is a lab that I did called DNA sequence comparison. I learned how things may be closely related to another thing more than another. I made a family tree with a chimp, human, mouse, chicken, wallaby, and goldfish. By making that tree I realized that some things may have the same physical feature but are not close to being related. Us humans are related more to mice than chickens and chickens are closely related to goldfish. The evolutionary distance between a mouse and a human is 75, between a wallaby and a human is 79, and between a chimp and a human is 99. There are a lot of different evidence that shows how evolution has took place.
There are many animals that have different features than those that live across the world. There are animals that I have seen pictures of that look very different than that species today. While watching the movie about Darwin traveling the world and seeing the same kind of bird with slightly different features made me realize that species have to adapt to their environment and those that cant eventually become extinct. I dont think Lamarck was correct because how can a Giraffe just be like "Oh those trees look good, let me just stretch my neck to reach them." That would be impossible and if that is the case, how would that physical feature get passed down to the next generation. Ive seen posters where monkeys turn into monkeys but they dont have me to convinced. People have talked about "cave men" walking on all four, similar to chimps, and now today us humans have evolved to walk on only two legs. Its crazy to think how closely related to them this makes us look. I am a very religious person and don't always agree but this subject has been quite interesting. Some time in life us humans evolved a lot. While doing an assignment I made a family tree with a few animals that I see no relationship with. This family tree showed me that we are closely related to mice somehow which I would have never guessed. Us humans talk and these animals have their own way of communicating. Its crazy to think that some point in life we looked similar to that and now somehow we are humans. Learning about evolution has taught me a lot and gave me a whole new look on the world.
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