Q 1. What are the sources of hydrogen for reducing CO2 in first photosynthetic organism?
Ans. The first photosynthetic organism probably used hydrogen sulphide as a source of hydrogen for reducing carbon dioxide to sugars.
Q 2. Which idea is known as endosymbiont hypothesis?
Ans. The eukaryotic cell might have evolved when a large anaerobic amoeboid prokaryotic ingested small aerobic bacteria and stabilized them instead of digesting them. This is known as endosymbiont hypothesis.
Q 3. What was the second idea of Lamarck called?
Ans. The second idea of Lamarck adopted, was called the inheritance of acquired characteristics. In this concept of heredity, the modifications an organism acquires during its lifetime can be passed along to its offspring e.g., the long neck of the giraffe.
Q 4. What is the important turning point for evolutionary theory?
Ans. The origin of species convinced most biologists that species are products of evolution. An important turning point for evolutionary theory was the birth of population genetics, which emphasizes the extensive genetic variation within populations and recognizes the importance of quantitative characters.
Q 5. How natural selection occurs?
Ans. Natural selection occurs through an interaction between the environment and the variability inherent in any population.
Q 6. What was the statement or theorem of Hardy-Weinberg?
Ans. It states that the frequencies of alleles and genotypes in a population's gene pool remain constant over the generation unless acted upon by agents other than sexual recombination.
Q 7. Which mating is called non-random mating?
Ans. Individuals with certain genotypes sometimes mate with one another more commonly than would be expected on a random basis. This is called non-random mating.
Q 8. On what evidence Darwin's theory of evolution was mainly based.
Ans. Darwin's theory of evolution was mainly was mainly based on evidence from the geographical distribution of species and from the fossil record.
Q 9. Who was Darwin's predecessor who developed a comprehensive model that attempted to explain how life evolves?
Ans. Jean Baptiste Lamarck (1744-1829).
Q 10. What is spirochete?
Ans. A helical bacterium which is flexible and has periplasmic flagella is called spirochete.
Q 11. Define bio-geography.
Ans. The study of geographical distribution of life on earth. Bio-geographers attempt to explain the factors that influence where species of plants and animals live on earth.
Q 12. What are fossils?
Ans. Any remain, impressions or traces of organisms of a formal geological age.
Q 13. Define embryology.
Ans. Study of animal development from fertilized egg to formation of all major organs.
Q 14. What is molecular biology?
Ans. The study of biochemical structures and function of organisms at molecular level.
Q 15. What does evolution refer?
Ans. Evolution refers to the processes that have transformed life on earth from its earliest forms to the vast diversity that is observed today.
Q 16. What is the concept of special creation?
Ans. According to the theory of special creation all living things came into existence in their present forms especially and specifically created by nature. Among the scientists who believed in divine creation was Carolus Linnaeus.
Q 17. What is the concept of Evolution.
Ans. The idea that organisms might evolve through time, with one type of organism giving rise to another type of organism is called evolution.
Q 18. What Darwin said about Finches of Galapagos?
Ans. Among the birds Darwin collected 13 types of finches that, although quite similar, seemed to be different species. Some were unique to individual islands, while other species were distributed on two or more islands that were close together.
Q 19. What did Lamarck said about the use and disuse of organs?
Ans. Lamarck argued that those parts of the body used extensively to cope with the environment become larger and stronger, while those that are not used deteriorate.
Q 20. What was Darwin's idea of Origin of Species?
Ans. A new species would arise from an ancestral form by the gradual accumulation for adaptations to different environment, separated from original habitat by geographical barriers. Over many generations, the two population could become dissimilar enough to be designated separate species.
Q 21. What was the contribution of Wallace in the development of theory of natural selection?
Ans. Alfred Wallace developed a theory of natural selection essentially identical to Darwin's. Wallace's paper, along with extracts from Darwin's unpublished 1844 essay, were presented to the Linnaean society of London on July 1, 1858.
Q 22. Define the theory of natural selection.
Ans. Nature will select the organism whose inherited characteristics fit them best to their environment and eliminate others.
Q 23. What is Neodarwinism?
Ans. According to neodarwinism the new species evolve due to extensive genetic variation within populations and natural selection.
Q 24. What does indicate that prokaryotes are ancestors of all life?
Ans. Evidence from biochemistry, molecular biology, and cell biology places prokaryotes as the ancestors of all life, and predicts that bacteria should precede all eukaryotic life in the fossil record.
Q 25. What are homologous structures?
Ans. Similarity in characteristics resulting from common ancestry is known as homology, and such anatomical signs of evolution are called homologous structures. For example: the forelegs(cat etc.), wings(bat), flippers(whale), and arms(man).
Q 26. What are vestigial organs?
Ans. Vestigial organs are historical remnants of structures that had important functions in ancestors but are no longer essential. For instance: vermiform appendix in carnivores and man.
Q 27. Name some vestigial structures in man.
Ans. Ear muscles, nictitating membrane, vermiform appendix and coccyx in man are vestigial structures.
Q 28. Differentiate between homologous and analogous organs.
Ans. Homologous organs are functionally different but structurally alike e.g., forelimbs of man, bat, horse, whale, etc., are example of divergent evolution. Analogous organs are functionally alike but structurally different e.g., wings of bat, birds and insects are examples of convergent evolution.
Q 29. Differentiate between natural selection and artificial selection.
Ans. Natural selection occurs through an interaction between the environment and the variability inherent in any population, while the selective breeding of domesticated plants and animals by man is called artificial selection.
Q 30. What is population?
Ans. Population is a group of inter-breeding individuals belonging to a particular species and sharing a common geographic area or a population is a localized group of individuals belongings to the same species.
Q 31. Define species.
Ans. A species is a group of individuals that have the potential to interbreed in nature.
Q 32. What is gene pool?
Ans. The total aggregate of genes in a population at one time is called the population's gene pool. It consists of all alleles at all gene loci in all individuals of the population.
Q 33. Define the Hardy-Weinberg theorem.
Ans. It states that the frequencies of alleles and genotypes in a population's gene pool remain constant over the generation unless acted upon by agents other than sexual recombination.
Q 34. What is Hardy-Weinberg equation used for?
Ans. A general formula, called the Hardy-Weinberg equation is used for calculating the frequencies of alleles and genotypes in populations at equilibrium.
Q 35. What factors affect the gene frequency?
Ans. Factors that affect that gene frequency:
- Mutation
- Migration
- Genetic drift
- Non-random mating
- Selection
Q 36. Differentiate between endangered and threatened species.
Ans. A species which is in imminent danger of extinction throughout its range is called endangered species. A threatened species is likely to become endangered in the near future.
Q 37. What are hydrothermal vents?
Ans. Hydrothermal vents are hot springs deep in the oceans, in underwater where life may have begun.
Q 38. Name any five species, declared extinct in Pakistan.
Ans. Cheetah, Tiger, Asian lion, Indian rhino, Crocodile, Cheer pheasant.
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