Question

DW 3. Discuss the term variation. Provide examples of variations on a particular species. Variation des differef Charolins les 11 4 Describe what is meant by competition among organisms. What do organisms antropole an calample of one is made Thom. Proster live longer compete for? Why? move 5. Explain the term adaptation. Provide an example of an adaptation in an organism. Adaptson means conditions, thitta determined which organisasi a Series Sure COP k evarirarenal Cind! 05. TODE á Darwin believed that sexual reproduction was a requirement for evolution. Discuss why. so that the desired adoption Lan spread. 7. Explain the phrase "survival of the fittest". Provide an example that explains The best adaption for their enroroment, & Reflection: Discuss what you think of Darwin's theory. Do you agree? Explain. I disagree with Darwin's Thoory belare 9. How does Darwin's theory explain the evolution of humans? According to Darwin why did our arms reduce in length while our legs increase in length? Darrin Thory e a plain the costution of humnas Exit Ticket: According to the theory of natural selection, discuss why polar bears have webbed toes. Infer what is likely to happen to the polar bears if climate change continues and the poles continue to get warmer.

Answer 1

1) According to Lamarck's theory of inheritance of acquired characters, changes in organisms are produced by needs and they occurred during the lifetime of the organism. Lamarck believed that the ancestors of modern giraffes had short necks and they stretched their necks to eat the leaves on higher heights and progressively their necks got elongated.

2) Lamarck's theory suggested that the characters acquired during the lifetime of an organism get transferred to the next generation, which is impossible. Because these characters cannot bring changes in the genes of the organism, hence not heritable.

3) Variations are the differences in characteristics between individuals within a species. Example; eye colour in human beings.

4) Competition is the interaction between two organisms, where both are harmed. Organisms can compete for various resources like food, water, mate, territory etc. Competition is to gain access to more resources which is essential for the organism's survival.

5) Adaptation is the evolutionary process, by which an organism can survive better in an environment. It can be any change in the structural or functional features of an organism. Eg: Polar bears are better adapted to the polar region.  Their white appearance act as a camouflage which helps them to stay unnoticed from prey and predator. They have thick fur and fat to escape from cold and small surface to volume ratio to minimise heat loss.

6) Sexual reproduction provides variation to offsprings, which helps them to survive better. Sexual reproduction can remove deleterious genes and bring in new combinations, which increases genetic diversity.

7) Organisms with best adaptations to the given environment survive, while with unfavourable characteristics will eventually be extinct. In other words, the form which leaves maximum copies will exist.

8) Some giraffes in a particular habitat have longer necks, while others have shorter necks. Once all the grass and leaves in the shrubs are over or dried off (say, summer and drought), the short-necked giraffes die off while the long-necked giraffes who have access to the tree foliage survived.

9) I think Darwin's theory is true. His theory of evolution by natural selection is validated by genetics, geology, palaeontology, developmental biology and various other scientific disciplines.

10) Through his book 'On the Origin of Species', Charles Darwin suggested the idea of evolution of new species from earlier ones. Humans are supposed to evolve alongside orangutans chimpanzees and gorillas and share a common ancestor almost 7 million years ago.

Early humans spent time in trees. Later they turned to be completely terrestrial, by evolving shorter arms and longer legs.

11) Polar bears live in ice-capped regions. The webbed foot helps polar bear in walking in the snow and swimming. Due to global warming, the ice caps are melting and polar bears face difficulty in finding food.