Chapter 5 Flashcards
- Explain the difference between abiotic and biotic factors. Habitat and niche.
Abiotic factors: Nonliving things that influence an organism (energy, nonliving matter, living space, and ecological processes). Biotic factors: All forms of life with which the organisms interact. Habitat: The space in which an organism lives; it’s defined by the biological requirements of each particular organism. Usually highlighted by prominent physical or biological features. Niche: The functional role (profession) the organism has in its surroundings. This term includes all the ways an organism affects the organisms with which it interacts as well as how it modifies its physical surroundings.
- What are limiting factors?
Limiting factors restricts species success if absent or there is a shortage of such entities. Scarcity of water or specific nutrients (plants). Climate, availability of specific food (animals).
- Explain Natural Selection.
Natural selection determines which individuals within a species will reproduce and pass their genes to the next generation. The changes seen in the genes and characteristics displayed by successive generations of a population of organisms over time is known as evolution. Several conditions and steps are involved in the process: 1. Individuals within a species show genetically determined variation. 2. Organisms within a species typically produce more offspring than are needed to replace the parents when they die. Most of the offspring die. 3. The excess number of individuals results in a shortage of specific resources. 4. Due to individual variation, some individuals have a greater chance of obtaining needed resources and therefore have a greater likelihood of surviving and reproducing than others. 5. As time passes, the percentage of individuals showing favorable variations will increase the percentage of showing unfavorable variations will decrease.
- Explain how competition can impact a population. How does the Competitive Exclusion Principal help us understand predator-prey relationships?
Competition is a kind of interaction in which two organisms strive to obtain the same limited resource. Intraspecific competition is competition between members of same species. Interspecific competition is competition between members of different species. The competitive exclusion principle holds that no two species can occupy the same ecological niche in the same place at the same time. Less-fit species must evolve into a slightly different niche.
- Explain symbiotic relationships…what types exist, how do they function?
Symbiosis is a close, long-lasting, physical relationship between two different species. At least one species derives benefit from the interaction. There are three categories of symbiotic relationships: Parasitism, Commensalism, Mutualism. Parasitism is a relationship in which one organism (parasite) lives in or on another organism (host), from which it derives nourishment. Ectoparasites live on the host’s surface. Endoparasites live inside the body of the host. Commensalism is a relationship in which one organism benefits while the other is not affected. Remoras and sharks. Mutualism is a relationship in which both species benefit. The relationship is obligatory in many cases, as neither can exist without the other. Mycorrhizae.
- What is keystone species?
Keystone species plays a critical role in the maintenance of specific ecosystems. When bison are present in American tallgrass prairie ecosystems, they increase the biodiversity of the site. Smaller plant species normally shaded by the tallgrasses are allowed to be successful. Bison wallows retain many species of plants that typically live in disturbed areas. Their feeding patterns affect the extent and impact of fire.
- Energy flows through organisms via carious paths. From this we can develop a food-web, food pyramid food chains etc. What is the relationship between energy flow and whether organisms are producers or decomposers?
The major roles played by organisms, the way energy is utilized within ecosystems, and the way atoms are cycled within ecosystems. Producers are organisms that can use sources of energy to make complex, organic molecules from the simple inorganic substances in their environment. Since producers are the only organisms in an ecosystem that can trap energy and make new organic material from inorganic material, all other organisms rely on producers as a source of food, either directly or indirectly. Consumers are organisms that require organic matter as a source of food. They consume organic matter to provide themselves with energy and the organic molecules necessary to build their own bodies. An important part of their role is the process of respiration in which they break down organic matter to obtain energy while they release inorganic matter. Decomposers could be considered another type of consumer because they cannot perform photosynthesis themselves, but we separate them into separate category because they use nonliving organic matter as a source of energy and raw materials to build their bodies. Since decomposers carry on respiration, they are extremely important in recycling matter by converting organic matter to inorganic material.
- Know the C,P, and N cycle. Explain how humans can impact each of these processes.
The carbon cycle involves the exchange of carbon dioxide between the atmosphere, plants through photosynthesis, animals through respiration, and the ocean through absorption. It also includes processes like decomposition and fossil fuel combustion, which release carbon dioxide back into the atmosphere. The phosphorus cycle focuses on the movement of phosphate, through the earths crust, water bodies, and living organisms. It involves weather of rocks, uptake by plants, consumption by animals, and the return of phosphorus to the environment through waste and decomposition. The nitrogen cycle involves conversion of atmospheric nitrogen gas into forms that can be used by living organisms, such as ammonia and nitrate. This process, know as nitrogen fixation, occurs through bacterial activity in the soil and in the roots of certain plants, Nitrogen is then taken up by plants, consumed by animals, and returned to the environment through waste and decomposition. Human impact: Burning of fossil fuels releases large amounts of carbon dioxide into the atmosphere. Fossil fuel burning also increases the amount of nitrogen available to plants. Converting forests (long-term carbon storage) to agricultural land (short-term carbon storage) has increased the amount of carbon dioxide I the atmosphere. If too much nitrogen or phosphorus is applied as fertilizer, or if it applied at the wrong time, much of the fertilizer is carried into aquatic ecosystems. The presence of these nutrients increases the growth rate of bacteria, algae, and aquatic plants. Toxic algae can kill fish and poison humans. An increase in the number of plants and algae results in lowered oxygen concentrations, creating “dead zones”.
