Heredity and Evolution
Short Questions
1. What is heredity?
Answer: Heredity is the transfer of biological characters from parents to offspring via genes.
2. Who is considered the pioneer of modern genetics?
Answer: Gregor Johann Mendel.
3. What did Hugo de Vries contribute to genetics?
Answer: He proposed the mutational theory explaining sudden hereditary changes.
4. What did Oswald Avery, Mclyn McCarty, and Colin McLeod prove in 1944?
Answer: DNA is the genetic material in most living organisms except viruses.
5. What is the process of RNA synthesis called?
Answer: Transcription.
6. What is a triplet codon?
Answer: A sequence of three nucleotides on mRNA coding for an amino acid.
7. Who discovered triplet codons for amino acids?
Answer: Dr. Har Govind Khorana.
8. What is a mutation?
Answer: A sudden change in a gene due to a nucleotide’s position change.
9. What is evolution?
Answer: The gradual change in living organisms over a long period.
10. What is the time duration of evolutionary changes mentioned in the document?
Answer: Approximately 300 crore years.
11. What are vestigial organs?
Answer: Degenerated or underdeveloped useless organs in organisms.
12. Name one vestigial organ in humans.
Answer: Appendix.
13. What are fossils?
Answer: Preserved remnants or impressions of organisms buried underground.
14. What is carbon dating used for?
Answer: Determining the age of fossils by measuring C-14 radioactivity.
15. What is a connecting link?
Answer: An organism with characters relating to two different groups.
16. Name one connecting link mentioned in the document.
Answer: Peripatus.
17. What does Darwin’s theory of natural selection emphasize?
Answer: Survival of the fittest organisms in a competitive environment.
18. What is Lamarckism based on?
Answer: The principle of use or disuse of organs causing morphological changes.
19. What is speciation?
Answer: Formation of new species due to genetic, geographical, or reproductive changes.
20. When did the Cro-Magnon man evolve?
Answer: About 50,000 years ago.
Long Questions
1. What is the role of DNA in the process of protein synthesis?
Answer: DNA stores the information needed to make proteins and starts the process by producing mRNA through transcription. The mRNA carries this information to the cytoplasm, where proteins are formed. This process ensures the body functions properly by creating necessary proteins.
2. How does the process of transcription work in cells?
Answer: Transcription involves synthesizing mRNA using one strand of DNA as a template. The mRNA sequence is complementary to the DNA strand, with uracil replacing thymine. This mRNA then moves to the cytoplasm to guide protein synthesis.
3. Why are translation and translocation important in protein synthesis?
Answer: Translation allows tRNA to bring amino acids that match mRNA codons to form proteins. Translocation is the ribosome’s movement along mRNA to read each codon in sequence. Together, they ensure accurate and continuous protein production in cells.
4. How do mutations impact living organisms and evolution?
Answer: Mutations are sudden gene changes that can be minor or cause serious disorders like sickle cell anaemia. Some mutations lead to new traits that may help organisms survive better. Over time, these changes can contribute to the evolution of new species.
5. What are morphological evidences, and how do they support evolution?
Answer: Morphological evidences are similarities in structures like the mouth or leaf shape among different organisms. These similarities suggest that the organisms share a common ancestor. This supports the idea that evolution occurred from a shared origin over time.
6. How do vestigial organs provide evidence for evolution?
Answer: Vestigial organs, such as the tailbone in humans, are useless but functional in other animals like monkeys. Their presence shows that humans evolved from ancestors with these functional organs. This supports the theory of gradual evolutionary changes.
7. Why are fossils significant in the study of evolution?
Answer: Fossils are remains of ancient organisms preserved in the Earth, showing their structures and lifestyles. Carbon dating helps determine their age, revealing when they lived. This information helps scientists understand how species evolved over millions of years.
8. What are connecting links, and how do they demonstrate evolution?
Answer: Connecting links, like lungfish, have traits of two groups, such as fish and amphibians. These organisms show how one group could evolve into another over time. They provide evidence of evolutionary transitions between different species.
9. What is Darwin’s theory of natural selection, and how does it work?
Answer: Darwin’s theory explains that organisms compete for survival, and only those with beneficial traits survive. Nature selects these fit organisms, allowing them to reproduce and pass on their traits. Over generations, this process leads to the formation of new species.
10. How did human evolution occur according to the document?
Answer: Human evolution started about 7 crore years ago from lemur-like ancestors, leading to ape-like animals like Ramapithecus. Over millions of years, these apes developed larger brains and erect posture, becoming skilled humans. By 50,000 years ago, modern Homo sapiens, like Cro-Magnon man, had evolved.
Leave a Reply