PLANT EVOLUTION DISPLAY Handout

Transcription

1 PLANT EVOLUTION DISPLAY Handout Name: TA and Section time Welcome to UCSC Greenhouses. This sheet explains a few botanical facts about plant reproduction that will help you through the display and handout. UCSC Greenhouses is open to the campus community every weekday from 9-3 and you can visit us on our website. Plant reproduction is very different from animal reproduction. In animal reproduction the product of meiosis is a gamete and in plant reproduction the product is a spore. This spore will grow into a haploid (1n) plant called a gametophyte. When this gametophyte is mature, the gametophyte will produce gametes. The gametes (egg and sperm) will fuse to form a zygote that grows into a mature diploid (2n) organism called a sporophyte. The sporophyte will undergo meiosis in some region of the plant and (1n) spores will be produced. This alternation between gametophyte generation and sporophyte generation is called the alternation of generations and is found in all plants. At the evolutionary beginning of multi-cellular plant life the gametophyte was the dominant generation. This means the sporophyte generation was very small and usually physically attached to, and dependent on the gametophyte. As plants evolved the gametophyte generation became smaller and less dominant and the sporophyte generation became larger and more dominant. In the most evolutionarily advanced plants, the flowering plants, the sporophyte generation is dominant and meiosis takes place in two locations. At the tip of the anther of a flower meiosis takes place and spores are produced. These spores grow into pollen grains, which are mature male gametophytes. The second location is inside the ovary of the flower where meiosis takes place and spores are produced. These spores grow into embryo sacs, which are the mature female gametophytes of flowering plants.

2 ALTERNATION OF GENERATIONS 1. What do sporophytes make after meiosis is complete? 2. What reproductive cells do gametophtes make? 3. What is formed by the union of male and female gametes? NONVASCULAR PLANTS: MARCHANTIA- LIVERWORT 4. Splashing rain water is important for this plants sexual reproduction compared to more ancestral plants which needed to be submerged in water to reproduce sexually? Which statement below is false? A. Being able to reproduce out of water enabled plants to become established on land. B. Being able to reproduce out of water increased their ability to survive changing environmental conditions such as droughts that may have lowered global water levels. C. Being able to reproduce out of water evolved due to natural selection. D. This was not an evolutionary advantage. FUNARIA-MOSS 5. Which sentence is correct? A. The gametophyte depend on the sporophyte for water and nutrients. B. The sporophyte depend on the gametophyte for water and nutrients. 6. The sporangium(plant organ that produces spores) produces a spore (diploid/haploid). VASCULAR PLANTS: PSILOTUM 7. What is not a competitive advantage of having vascular tissue? A. Raises sporangia higher for better dispersal of spores. B. Plant can grow taller and better compete for light. C. Plants with vascular systems can grow in areas where the water is deep in the soil D. Plants with vascular tissue reproduce more offspring.

3 SELAGINELLA 8. Heterosporous plants produce (one/two) type of spores ; Homosporous plants produce (one/two) type of spores. 9. Which define of evolution is correct and complete. A. Evolution is the survival of the fittest over generations. B. Evolution is the change in fitness of a species. C. Evolution is the change allele frequencies of a population over generations. D. Evolution is natural selection within a species. 10. What evolutionary advantage would be recognized by separating the gametes as heterosporous plants do? A. Greater chance of cross fertilization. B. Higher percentage of reproduction. C. More gametes being produced. D. Less chance of mixing allele frequency within a population. POLYPODIUM-FERN 11. Ferns are homosporous, How does this increase the survival advantage? A. Homosporous species do not have much genetic variation in the population. This can be advantageous in unchanging environments. B. Homosporous species evolve slowly and therefore have no survival advantage. C. Homosporous species can adapt best to radically changing environments. D. If the parent plant thrives in a location its offspring may be at a disadvantage with a very similar genotype. 12. If the environment changes which species has more of an advantage homosporous or heterosporous species? SEED PLANTS 13. The pollen grain is a male gametophyte. In Gymnosperms it travels to the female by water or wind?

4 14. What is not a morphological adaptation gymnosperms have undergone to reduce water loss. A. Developed a thick cuticle, B. Reduced size of leaves, C. Stomata are in sunken pits D. They grow closer to water sources. 15. Seed plants (Angiosperms and Gymnosperms) all have non-motile sperm. Is this trait Synapomorphic or Symplesiomorphic when looking at ALL ancestral plants. 16. Is this trait Synapomorphic or Symplesiomorphic when looking at just the Angiosperm group? 17. Seed development was an adaptation that increased survival rates for the gymnosperms and angiosperms. What was not a factor? A. Megagametophyte or endosperm provides food for the developing embryo, B. Seeds can germinate when conditions are advantageous, C. Seed coats add protection to embryo D. Seed development increased natural selection. ANGIOSPERMS-FLOWERING PLANTS 18. Why is endosperm important? A. It is the first step in plant reproduction. B. It is how the sperm is produced. C. It is a source of food for the embryo D. It increases genetic diversity. 19. What is not an advantage of flower fragrance, color, or nectaries? A. They attract (or help attract) pollinators. B. Colors can guide the insects to land on the flowers in a way that helps attach pollen to the insect. C. They can trap insects such as carnivorous plants do. D. Different fragrances, colors and nectaries between plant species will attract specific insects to that specific species therefore less pollen needs to be made.

5 20. Presently flowering plants make up the majority of species of plants on the earth. One reason for their success is that they have coevolved with what group of animals? (Hint: These animals disperse the flowering plants male gametophtes to other flowers.) 21. Many flowering plant species produce a swollen ovary (fruit). How does this benefit the species? A. Attracting animals that feed on the fruit and disperse seed, B. Fruit benefits the species as it reduces the need for the plant to produce sugar. C. Fruit is a major part of the asexual reproduction process D. Fruit is always the best way for any plant to spread its seed.