There are 9 questions. Please help me answer these questions because I’m struggl
ID: 272026 • Letter: T
Question
There are 9 questions. Please help me answer these questions because I’m struggling a bit!Thank you! Possible Essay Questions Ch 22.2 and 22.3: How do homologies support the concept of evolution? Include convergent evolution in your discussion. Ch 22.2, 22.3: Discuss 2 different lines of evidence that support the theory of evolution. Ch 22: Explain what it means to share a common ancestor. Argue the point that we do not come from Monkeys, but rather share a common ancestor Ch 23: Of all the mechanisms of evolution, natural selection is adaptive while the others are not. Explain. Ch 23: How does sexual selection sometimes lead to sexual dimorphism? Ch 23: Some organisms seem poorly designed: ostriches can't fly, whales spend most of their life under water but they can't breathe in water, etc. How do "poor designs" found in nature support the theory of evolution? Ch. 24: Discuss two means of sexual isolation and how they arrest gene flow Ch 28: Briefly describe the life cycle of a fern. Include key points like gametophyte, diploid, etc. Include a dlagram (s) to make your point clear. I don't need good artistry-just clarity Ch 28: Compare and contrast a moss and a conifer or flowering plant. Both are plants and therefore similar, but they are also different Be able to explain how each of the following supports the idea that species change through time: artificial selection; extinction; vestigial traits antiblotic resistance.
Explanation / Answer
Bryophytes are generally called as non-vascular plants. These plants lack vascular tissue that helps in the transport of water and minerals to the plant. They mainly consist of mosses, liverworts and hornworts. Life history includes a dominant gametophyte (haploid) stage. The haploid gametophyte (produces gametes for sexual reproduction) alternates with diploid sporophyte (producing spores for asexual reproduction). For sexual reproduction, the moss gametophyte produces gametangia. The male and female gametangia may be on the same thallus or on separate thallus. This means that gametophytes can be homothallic or heterothallic. The female sex organ is the archegonium and the male sex organs are antheridia. Both the antheridium and archegonium have a sterile jacket of cells which protects gametes. Archegonium contains ovum, while antheridium produces spermatozoids. These spermatozoids swim to reach archaegonia via chemotaxis. Sexual reproduction is oogamous type. After fusion, zygote is formed inside archaegonia which is diploid in nature. The fusion of sperm and egg fuse is called syngamy. The sporophyte grows and nutrients for the developing sporophyte are provided by the gametophyte. It acts as a parasite on the gametophyte. The sporophyte usually consists of a basal foot, an elevating seta and sporangium called the capsule. Spores are produced as a result of meiosis. When spores mature, the lid of the capsule, called the operculum breaks open and spores are released. The gametophyte plant is produced by the germination of a haploid spore. The spore germinates to produce a branched filament of photosynthetic cells called a protonema. This structure develops into a leafy moss gametophyte which is haploid. The life cycle continues.
Mosses
Conifers
Flowering plants
Mostly found in moist shady habitats.
Do not prefer moist shady habitats.
Do not prefer moist shady habitats.
Non-vascular
Vascular
Vascular
Roots are not well developed. Rhizoids are found.
Roots are present.
Well developed roots are present
Do not produce seeds
Seeds are produced
Seeds are produced
Seeds are not produced
Seeds are not enclosed in fruit
Seeds are enclosed in fruit
Scaly leaves are not present
Scaly or needle like leaves are present
Scaly leaves are not present
Include small plants
Include tall trees
Include herbs, shrubs and trees
Non-flowering plants
Non-flowering plants
Flowering plants
Commonly called as mosses
Called as gymnosperms
Called as angiosperms
Certain reproductive characteristics prevent species from fusing or mating. This could be due to various reasons. Two types of isolating mechanisms between species include pre-mating and post mating isolating mechanisms. Some factors make the species to mate with their own kind. In certain cases individuals of different species do not mate because they are active at different times of day or in different seasons. In post mating mechanisms genomic incompatibility, inviable hybrids, sterility does not allow mating to take place. All these factors prevent the populations of the same species to exchange genetic material or gene flow is blocked resulting in formation of allopatric species.
The difference in appearance of males and females of the same species is referred as sexual dimorphism. The differences can be in color, shape, size, and structure. These changes can be caused by inheritance of one or the other sexual pattern in the genetic material. A form of natural selection is the selection of traits that got apparently selected through time because they increased the reproductive success/capacity of their bearers is called as sexual selection.
Mosses
Conifers
Flowering plants
Mostly found in moist shady habitats.
Do not prefer moist shady habitats.
Do not prefer moist shady habitats.
Non-vascular
Vascular
Vascular
Roots are not well developed. Rhizoids are found.
Roots are present.
Well developed roots are present
Do not produce seeds
Seeds are produced
Seeds are produced
Seeds are not produced
Seeds are not enclosed in fruit
Seeds are enclosed in fruit
Scaly leaves are not present
Scaly or needle like leaves are present
Scaly leaves are not present
Include small plants
Include tall trees
Include herbs, shrubs and trees
Non-flowering plants
Non-flowering plants
Flowering plants
Commonly called as mosses
Called as gymnosperms
Called as angiosperms
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