Question

BIOL 1020 Homework Evolution & Natural Selection 4 NATURAL SELECTION: 1. In your OWN words, explain what natural selection is. What is required? What is the result? 2. True or false? For natural selection to work, a population must have genetic variation. Explain your answer. 3. List three sources of genetic variation in a population. Identify which sources are most important for asexually reproducing organisms. Which method is most important for sexually reproducing organisms? 4. List three mechanisms which cause allele (gene) frequency changes (evolution). Note: Questions 3 and 4 are often confused by students. One is sourd mechanisms for evolution. There is a difference. rces of genetic variation. One is 5. What is Hardy-Weinberg Equilibrium? Why is this idea important? What does it mean if a population is IN or OUT of H-W equilibrium? Explain in your OWN words. 6. What is a bottleneck effect? How do human activities, including habitat destruction, affect populations of wildlife? Explain. Homework Evoluti A Plant Life Cycle The plant life cycle demonstrates the alternation of generations. Note, this phenomenon does NOT occur in the animal life cycle. Members of kingdom Plantae alternate between HAPLOID and DIPLOID forms. The haploid generation has one copy of each chromosome (n), while the diploid generation has two copies of each chromosome (2n). In this life cycle, an unfertilized haploid cell (SPORE) grows into a multicellular haploid GAMETOPHYTE, The gametophyte produces gametes (sperm = male gamete & egg female gamete), which fuse at fertilization to produce a diploid zygote. The zygote eventually matures into the multicellular diploid SPOROPHYTE, which will later produce spores via meiosis Answer the following questions about the plant life cycle. 5. This multicellular form dominates the haploid generation: Gametophyte c. Zygote b. Gametophyte a. Sporophyte Egg Spermi Spore HAPLOID ( GAMETOPHYTE GENERATION fuse at fertilization to produce a diploid zygote. 6 c. Spores b. Diploid Gametes a. Haploid Gametes Fertlzation Melosis DIPLOID (2n SPOROPHYTE GENERATION 7. Spores develop into the multicellular haploid Zygote Gametophyte b. Sporophyte a. Embryo Embryo Sporophyte Access the following photosynthesis tutorial and answer the following questions. https://www.youtube.com/watch?v Gfgoni5i48 8. True or False? The process of photosynthesis requires sunlight, carbon dioxide, water and nutrients. 9. Complete the equation: 6CO26H2O>> sunlight >> 10. Which of the following prevent/s water loss? c. Cuticle b. Xylem a. Stomata 11. Tubes that carry water in plants are called 12. Tubes that carry food in plants are called 13 Structures that allow exchange of gases in leaves are called

Answer 1

1. Natural selection is the driving force that brings about evolution. It favors individuals with beneficial adaptative variations. Hence, the organisms with better-adapted traits that increase their reproductive fitness are able to leave more progeny. With time, the population evolves to have the number of individuals with better-adapted features. It is required when populations are exposed to any change in the surroundings. The result is the evolution of the population with better adaptive variations.
2. True, Natural selection chooses the beneficial adaptative variations from the gene pool. hence it required genetic variations to occur.