SHORT ANSWER (points as noted 20.Briefly explain why parasites are important to
ID: 220221 • Letter: S
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SHORT ANSWER (points as noted 20.Briefly explain why parasites are important to the health of the ecosystem as a whole.(2 pts) 21. How does the feeding mechanism of sponges differ from that of jellyfishes? (In your answer, be sure to mention the specific cell types that are unique to each group.) (2 pts) 22. Write a brief summary (~4 sentences) of the evolutionary history of animals. (4 pts) 23. In lecture, we identified three main differences between protostomes and deuterostomes. List two of those differences. (2 pts) 24. A body plan of an animal is a set of distinct morphological and developmental traits. In lecture, we identified four main ways of categorizing animals based on their body plans; one of these ways was body symmetry. What are the other three ways? (3 pts)Explanation / Answer
Answer No. 20: The effects of parasitism on ecological communities can be particularly pronounced when the hosts are keystone or dominant species with important functions in an ecosystem. As an Example, our immune systems have evolved to cope with a certain amount of infections. So if we aren't exposed to parasites and other diseases when we're young, our immune systems don't develop properly and can start attacking our own bodies. This may cause allergies and autoimmune diseases. On the other hand, parasites keep down the numbers of plant-eating insects and other animals we consider pests. Within months, these species would increase in numbers and cause serious damage to food crops, As a result, we would have to use even more pesticides, which would affect wildlife.
Answer No. 21: Sponges have a unique feeding system among animals. Instead of mouths, they have tiny pores (ostia) in their outer walls through which water is drawn. Cells in the sponge walls filter food from the water as the water is pumped through the body and the osculum. The flow of water through the sponge is in one direction only.
Jellyfishes eat a wide range of crustaceans and fish, which they capture using their nematocysts. The nematocysts are located throughout the tentacles that spread downward from the edge of the umbrella dome, and also cover the four or eight oral arms that hang down from the central mouth.Food and waste must be passed in and out through the same opening since like other Cnidarians, they have no digestive tract. Cilia within the digestive cavity transport water, food, and gases around.
Answer No. 22: Early animal life, termed Ediacaran biota, evolved from protists at Pre-Cambrian Era, as they were only tiny, sessile, soft-bodied sea creatures. The Cambrian period marks the most rapid evolution of new animal phyla and animal diversity in Earth’s history. It is believed that most of the animal phyla in existence today had their origins during this time, often referred to as the Cambrian explosion. Echinoderms, mollusks, worms, arthropods, and chordates arose during this period. One of the most dominant species during the Cambrian period was the trilobite, an arthropod that was among the first animals to exhibit a sense of vision. In Post-Cambrian Evolution, Continual changes in temperature and moisture encouraged the development of new adaptations to terrestrial existence in animals, such as limbed appendages in amphibians and epidermal scales in reptiles. The disappearance of some dominant species of Permian reptiles made it possible for a new line of reptiles to emerge, the dinosaurs. The warm and stable climatic conditions of the ensuing Mesozoic Era promoted an explosive diversification of dinosaurs into every conceivable niche in the land, air, and water.
Answer No. 23: The majority of coelomate invertebrates develop as protostomes in which the oral end of the animal develops from the first developmental opening, the blastopore. In the deuterostomes, including Echinodermata and the ancestors of the Chordata, the oral end of the animal develops from the second opening on the dorsal surface of the animal; the blastopore becomes the anus. At The time of the Eight-cell stage, the cleavage of protostomes is spiral and determinate, whereas the cleavage of deuterostomes is radial and indeterminate.
Answer No. 24: The other ways are: 1) Presence of true body cavity, called a coelom. This is a space between the body tissues and internal organs, and it allows for independent movement and growth of those organs.
2) By their Digestive System. How it works, What are the openings, How they take up food?
3) Location of Animals Body Structures.
4) Embryological Development.
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