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From Wikipedia

Pedogenesis

Pedogenesis or soil evolution (formation) is the process by which soil is created. It is the major topic of the science of pedology, whose other aspects include the soil morphology, classification (taxonomy) of soils, and their distribution in nature, present and past (soil geography and paleopedology).

Climate

Climate regulates soil formation. Soils are more developed in areas with higher rainfall and more warmth. The rate of chemical weathering increases by 2-3 times when the temperature increases by 10 degrees Celsius. Climate also affects which organisms are present, affecting the soil chemically and physically (movement of roots).

Organisms

The organisms living in and on the soil form distinct soil types. Coniferous forests have acidic leaf litter and form what are known as inceptisols. Mixed or deciduous forests leave a larger layer of humus, changing the elements leeched and accumulated in the soil, forming alfisols. Prairies have very high humus accumulation, creating a dark, thick A horizon characteristic of mollisols.

For example three species of land snails in the genus Euchondrusin theNegev desert are noted for eating lichens growing under the surface limestone rocks and slabs (endolithic lichens). They disrupt and eat the limestone. Their grazing resulting in the weathering of the stones, and the subsequent formation of soil. They have a significant effect on the region: the total population of snails is estimated to process between 0.7 and 1.1 metric ton per hectare per year of limestone in the Negev desert.

Parent Material

The rock from which soil is formed is called parent material. The main types are: aeolian, glacial till, glacial outwash, alluvium, lacustrine parent material and residual parent material, or bedrock.

Pedologists use the following generic functional relationship for understanding soil formation:

s = f (cl, o, r, p, t, ...)

where s - soil properties; cl - regional climate; o - potential biota; r - topography; p - parent material; t - time; ... - additional variables.

Examples

A variety of mechanisms contribute to soil formation, including siltation, erosion, overpressure and lakebed succession. A specific example of the evolution of soils in prehistoric lake beds is in the Makgadikgadi Pans of the Kalahari Desert, where change in an ancient river course led to millennia of salinity buildup and formation of calcretes and silcretes.



From Yahoo Answers

Question:18. List the characteristics common to all animals. Name at least three 19. How do structures of the digestive tracts of a flatworm and an earthworm differ? 20. How is a sponge s food-gathering technique adapted to its sessile lifestyle? 21. A biologist places a single, living sponge in a saltwater tank. After several weeks, the biologist observes other small sponges living in the tank. Because the biologist is certain that no other sponge was introduced into the tank, what other explanation could you provide to explain the observation? 22. Describe the body of a leech. In what way do the leech s adaptations make it suited for its niche?

Answers:18. they all respire, grow and excrete 19. an earthworm has a larger surface area and is more complex, flatworm does not digest almost 20. a lot of volume to be able to create more suction 21. binary fission, hermaphrodity, natural cloning, budding 22. large mouth relative to body, large storage capacity, sticky

Question:18. List the characteristics common to all animals. Name at least three 19. How do structures of the digestive tracts of a flatworm and an earthworm differ? 20. How is a sponge s food-gathering technique adapted to its sessile lifestyle? 21. A biologist places a single, living sponge in a saltwater tank. After several weeks, the biologist observes other small sponges living in the tank. Because the biologist is certain that no other sponge was introduced into the tank, what other explanation could you provide to explain the observation? 22. Describe the body of a leech. In what way do the leech s adaptations make it suited for its niche?

Answers:18. All animals are made up of eukaryotic cells, they're all heterotrophs, and they all have a soft cell membrane. 19. flatworm's ingest food and then waste material is forced back out of the mouth where as a roundworm ingest food via the mouth and excretes waste out of the anus. 20. It filters the water that passes by it and extracts the nutrients. 21. Pieces of the sponge may have broken off during handling and they reattached themselves in another area and grew into a new sponge. 22. It has an anterior (head region) sucker which secretes an anesthetic so the host isn't aware of it's presence, and it draws in blood. It also secretes an anti-clotting enzyme.

Question:Which is NOT a major evolutionary trend observed in invertebrate animals? (Points : 1) a change from radial symmetry to bilateral symmetry the development of a head with sensory organs the formation of a digestive tube inside a tubular body a change from a segmented body to a sac-like body 6. The four-stage life cycle of an insect such as a bee is called __________. (Points : 1) alternation of generations complete metamorphosis incomplete metamorphosis sexual regeneration 7. Which of these are adaptations of sponges for filter feeding? (Points : 1) tentacles, nematocysts, and polyps madreporite, tube feet, and canals ostia, osculum, and collar cells mouth, pharynx, and stomach 8. Which of these structures is a characteristic of the phylum Cnidaria? (Points : 1) medusa radula coelum tail 9. Which phylum is NOT entirely composed of aquatic invertebrates? (Points : 1) Annelida Cnidaria Echinodermata Porifera 10. Which type of invertebrate has many organ systems and a body plan with radial symmetry? (Points : 1) annelids cnidarians echinoderms flatworms 11. Which phylum is made up of invertebrates with the most advanced stage of cephalization? (Points : 1) Arthropoda Mollusca Nematoda Porifera 12. Which characteristic do all invertebrates share? (Points : 1) no cells no backbone no nerves no skeleton 13. Which list shows invertebrates in order of INCREASING complexity of tissue and body development? (Points : 1) sea stars, leeches, hookworms, corals corals, hookworms, sponges, planarians earthworms, hydras, sea stars, leeches sponges, hydras, flatworms, earthworms 14. For gathering food, mollusks have a rasping and scraping organ called a __________. (Points : 1) mantle nephridium pharynx radula 15. Which of the following is NOT a class of mollusks? (Points : 1) Gastropoda Crustacea Bivalva Cephalopoda 16. Which of the following animals displays bilateral symmetry? (Points : 1) sponge coral squid sea star 17. All of these groups of invertebrates have a coelom EXCEPT __________. (Points : 1) echinoderms nematodes mollusks annelids 18. Which of the following is NOT part of the phylum Arthropoda? (Points : 1) insects spiders worms crustaceans 19. Which of the following is NOT a phylum of worms? (Points : 1) Porifera Nematoda Platyhelminthes Annelida 20. The exoskeletons of arthropods contain __________. (Points : 1) radula collar cells book lungs chitin 21. Match each phylum name with its examples. (Points : 5) Answer Potential Matches: : 1.Arthropoda 1 : sea slugs and garden snails : 2.Annelida 2 : leeches and polychaete worms : 3.Cnidaria 3 : lobsters and centipedes : 4.Echinodermata 4 : corals and sea anemones : 5.Mollusca 5 : brittle stars and sea cucumbers

Answers:6. Complete Metamorphosis 7. ostia, osculum, and collar cells 8. medusa 9. Annelida 11. Nematoda 12. No backbone. 15. Cephalopoda 16. Squid 17. Nematodes (fairly sure ~80%) 18. worms 19. Porifera 20. Chitin 21. Arthropoda - lobsters and centi Annelida - Leeches and polychaete worms Cnidaria - corals, sea anemones (and jellyfish) Echinodermata - brittle stars & sea cucumbers Mollusca - sea slugs and garden snails. Make sure you know why on all of these, as Yahoo will not be able to help you on your test.

Question:A. niche. B. habitat. C.community. D.behavior. 2.The idea that two species cannot occupy the same niche is known as A. ecological equivalence. B. niche partitioning. C. evolutionary response. D. competitive exclusion. 3. Ecological equivalents are species that occupy similar niches A. in different geographical regions. B. with plenty of food. C. in different types of habitats. D. after niche partitioning. 4.Predation is best described as A.one organism capturing and eating another. B. two organisms competing for limited resources. C. an interaction in which two species benefit from each other. D. an interaction in which one species benefits and the other is not affected. 5. An oak tree provides a sparrow a place to build a nest. The nest neither benefits nor harms the tree. What is the name for this type of relationship? A.mutualism B. commensalism C. predation D. parasitism 6. The movement of a single caribou into a herd is an example of A. immigration. B. emigration. C. population. D. competition. 7. The carrying capacity is most likely to change A. if emigration takes place. B. when resources remain the same. C. for all species at the same time. D. after a fire or flood. 8. Which of the following is an example of a density-independent limiting factor? A. a parasite B. a decrease in prey C. a food shortage D. a natural disaster 9. Which Earth system includes all the other Earth systems? A. geosphere B. biosphere C. hydrosphere D. atmosphere 10. Which of the following is an example of a connection between Earth systems? A. deer drinking from a stream B. ice melting on a lake C. minerals forming under Earth's surface D. a robin hatching from an egg 11.A biome is defined by its A.wetland. B. mountainside. C. African savannah. D. tropical rain forest. 12. Which biome has hot summers, cold winters, and precipitation spread over the whole year? A. mountainous coniferous forest B. Mediterranean shrubland C. temperate deciduous forest D. tropical rain forest 13. Which two areas are not considered to be biomes? A. polar ice caps and chaparral B. mountains and tundra C. polar ice caps and mountains D. chaparral and grassland 14. Lions eat zebras. Zebras are part of the lion's A. abiotic factors. B. ecological niche. C. distant habitat. D. predators. 15. When two species compete for the same resource, they sometimes divide this resource. This is an example of A. niche partitioning. B. niche consolidation. C. evolutionary response. D. ecological equivalence. 16. Hawks and foxes compete to eat field mice. This is a form of A. interspecific competition. B. competitive exclusion. C. intraspecific predation. D. random dispersion. 17. (no help needed) 18. Which of these is an example of parasitism? A. A lion defends its territory. B. A squirrel stores food in a tree hole. C. A leech feeds on a host's blood. D. A polar bear kills and eats a seal. 19. (no help needed) 20. Which of the following is a density-dependent limiting factor? A. unusual weather B. normal weather C. human activities D. competition 21. All of the living things in the bioshpere are called the A. biota B. biome C. abiota D. biomic component 22. The geosphere is one of four interconnected systems, and includes A. continents, rocks, and sea floor only. B. the features on and below Earth's surface. C. all nonliving parts of Earth. D. every living thing on Earth. 23. The hypothesis that suggests that Earth s systems interact to produce abundant life in the biosphere is called the _____ hypothesis. A. Gaia B. Biome C. Grays D. Abiotic 24. Which of the following is a characteristic of tropical rain forests? A. a distinct rainy season B. few organisms living in trees C. extreme heat fluctuations D. thin soil that is low in nutrients 25. (no help needed) Before you tell me to do my homework, I've been working on this assignment for awhile. I'm not just being lazy. I've never even asked for help with homework here...but the end of the semester is coming up, and I'm desperate. Any help is appreciated. Also, I don't expect anyone to do this entire assignment for me. Just some help would be nice.

Answers:Some more that I can do. 2. D 12. C 14. B 18. C 21. A 22. B 24. C I agree on Nevermore's answers except 10, I'd say it's A (the deer being part of the biosphere, i.e. living organisms, and the stream being part of the hydrosphere, i.e. water systems).