Question

11. What is the theory of fixed species? Explain why fossils represented a problem for this theory. Briefly state why the theory of fixed species predominated for such a long period of history.

12. Describe Lamarck’s explanation for the evolution of species. Were his hypotheses eventually supported or rejected? Explain how his observations played a role in the study of evolution.

13. What are Darwin’s major contributions to the theory of evolution?

14. Explain how the fossil record and homologous structures are evidence for evolution.

15. Which of the following is evidence for common ancestry: analogous or homologous structures? What are some examples of each?

16. Explain how phylogenetic/evolutionary trees are created and what they represent. Know how to interpret them! What do the branch points represent?

17. Define natural selection. Make sure to address how mutations contribute to it. Then give some examples.

18. Define a population. Compare that to a community and ecosystem. What do each of these categories include?

19. Describe genetic drift. How is this different from selection? Does it usually occur in small or large populations?

20. Distinguish between the following concepts: a. the bottleneck effect and the founder effect b. directional selection, disruptive selection, and stabilizing selection c. artificial selection and natural selection.

Answer 1

1. Fixed species: The species which does not change or does not give rise to any diveersee species are called fixeed species.

• The fossils which are found are generally diverse catagory and there are variation of single species,even many fossils also evident that one species arise from another( like the archaeopteryx).So the fossils does not support this theory.
• The species are generally tend to be diverse which means that they give rise to other species so the fixed species are not applicable in the history.

12. According to the Lamark's theory of evolution: an organism can skip on to its offspring physical characteristics that the determine organism obtained through use or disuse in the course of its lifetime. This concept is also known as the inheritance of obtained traits or smooth inheritance.

• The therory of Lamark or the Neo Lamarkism was supported by many scientiest of the world,while some weere also against this theory.
• According to this observation the acquired characters are transfered to the next generation,but at that time he was unable to how the characters are get transferred to the offsprings.And for this the concept of genetics,epigenetics arises.By this the study of evolution became more evolved.

13. Charles Darwin's idea of evolution states that evolution occurs through herbal choice. Individuals in a species show variant in bodily traits. Individuals with traits satisfactory desirable to their environment are more likely to live to tell the tale, locating meals, heading off predators and resisting disease.

• By this theory and his observation Derwin eexplained that the characters which are acquired through the natural selection and the species which can suit the enviournment most give rise to the next generation so that the species can exists in the enviournment.His idea was also able to explain that how the species become extinct in the nature.

14. The homologus structure in the fossil records represented that the species have some similarity between them. Even the homologus structure also able to explain that how one species is related to the other,from this evolution can be explain.

15. Homology, in evolution, common in the structure, biiological system, or development of different species of organisms based upon their descent from a commonplace evolutionary ancestor. Homology is contrasted with analogy, that is a purposeful similarity of shape based totally not upon commonplace evolutionary origins however upon mere similarity of use.

Analogous systems aren't always evidence that species got here from a not unusual ancestor. It is more likely they got here from separate branches of the phylogenetic tree and might not be closely related in any respect.

So the homologous structure is able to explain about the common ancestry.

• Example: Wings are a popular edition for many animals. Bats, birds, bugs, and pterosaurs all had wings. But a bat is extra intently related to a human than to a fowl or an insect based totally on homologous structures. Even although these kinds of species have wings and might fly, they're very exclusive in other ways. They just happen to fill the flying niche of their places.

16. Phylogenetic tree, also known as Dendrogram, a diagram showing the evolutionary interrelations of a set of organisms derived from a not unusual ancestral shape. The ancestor is within the tree “trunk”; organisms which have arisen from it are placed at the ends of tree “branches.” The distance of 1 organization from the alternative agencies indicates the degree of courting; i.e., closely related companies are placed on branches near one another. Phylogenetic trees, even though speculative, provide a convenient approach for reading phylogenetic relationships.

• From the tree the root,branch all are important the root is the origin of the common ancestor,ther branch point is the species differentiation point.All this trees have been created on the basis of the organ & structure homology and their period of existance.
• The branch point represents differentiation point of the species.

17. Natural selection: The system whereby organisms higher tailored to their surroundings tend to live to tell the tale and produce extra offspring. The idea of its motion turned into first completely expounded by means of Charles Darwin, and it's far now appeared as be the primary system that brings approximately evolution.

• Mutation is often generated in the species in random manner but the natural selection decides which mutation will be selected and which will be eleminated.
• Example: The peppered moth exists in both mild and darkish colorations in Great Britain, however at some point of the commercial revolution, most of the trees on which the moths rested have become blackened with the aid of soot, giving the dark-colored moths a bonus in hiding from predators. This gave dark-coloured moths a better chance of surviving to provide dark-colored offspring, and in only fifty years from the primary darkish moth being stuck, nearly all the moths in industrial Manchester were dark. The dark moths became uncommon again, demonstrating the affect of natural selection on peppered moth evolution. A latest look at, the usage of photograph analysis and avian vision models, shows that faded people greater intently suit lichen backgrounds than dark morphs and for the first time quantifies the camouflage of moths to predation threat.