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ECOLOGY- the branch of biology that studies the interactions between organisms and their environment. Ecological studies reveal interrelationships between living and non-living parts of the world.
Components of a Biosphere
1) population: * includes all the members of a species in a given area ex. all of the white tail deer in the Honey Island Swamp is a population 2) community: * all of the populations in a given area ex. all of the organisms in the Honey Island Swamp-- deer, palmetto bushes, rabbits, cypress trees, squirrels, raccoons, birds blackberries, etc... is a community
Cont… 3) ecosystem: * the living (biotic) community and the nonliving (abiotic) physical environment functioning together is an ecosystem ex. the swamp ECOSYSTEM is made up of the BIOTIC community and the ABIOTIC factors-- weather, rocks, water, soil 4) biosphere: * the biosphere is the portion of the earth in which LIFE exists * is made up of many complex ecosystems * ALL OF THE ECOSYSTEMS COMBINED MAKE UP THE BIOSPHERE!
Write in notes as a flow map
ALL ABOUT ECOSYSTEMS * the ecosystem is the structural and functional unit that is studied in ecology * they involve important interactions between biotic and abiotic factors * an ecosystem can support itself and is stable (not much change) when three conditions are met...the E.A.R. conditions...
E.A.R Conditions 1) there must be a constant supply of Energy (the sun is this source for all life on earth) 2) there must be living organisms that can convert the energy into organic compounds (plants--Autotrophs--photosynthesis) 3) there must be a Recycling of materials between organisms and the environment. A balanced aquarium is an example of a very small ecosystem. It is self-supporting because the requirements for a stable ecosystem are present:
Cont.. ENERGY (1) is supplied to the ecosystem by light. There are PLANTS (2) to change the light energy into the organic molecule of energy (glucose). RECYCLING (3) of materials occurs during photosynthesis and respiration.
During photosynthesis, plants use light energy and carbon dioxide to form glucose. They give off oxygen. Animals release the carbon dioxide that is used by plants.
PARTS OF AN ECOSYSTEM
A) ABIOTIC FACTORS * the non-living parts of the environment (water, air soil, rocks etc.) * they directly affect the ability of organisms to live and reproduce * abiotic factors can vary from place to place * abiotic factors can act as LIMITING FACTORS that keep a population at a certain level ex. desert environment -- hot temperature and little water are examples of limiting factors -- different species living in the desert are LIMITED mainly to those types of plants and animals that need very little water and can survive extreme temperatures
B) BIOTIC FACTORS * all the living things that directly or indirectly affect the ecosystem (all living components-plants animals, microorganisms) * biotic factors interact with other living organisms and the physical environment * can also be LIMITING FACTORS ex. disease (bacteria), predators, food resources
1) Nutritional Relationships:
* involves the transfer of nutrients from one organism to another within an ecosystem a) AUTOTROPHS-- * organisms that can synthesize organic molecules from inorganic molecules * also called producers * can be either photosynthetic or chemosynthetic
b) HETEROTROPHS--. organisms that cannot manufacture organic molecules
b) HETEROTROPHS-- * organisms that cannot manufacture organic molecules * there are 5 types of heterotrophs i. HERBIVORES-- * organisms that eat only producers (plants) * also called a primary or first-level consumer ex. cows, elephants, goats ii. CARNIVORES-- * organisms that eat only other animals * also called a secondary (or tertiary--3) consumer ex. tigers, lions, wolves
iii. OMNIVORES--. organisms that eat everything
iii. OMNIVORES-- * organisms that eat everything * can be a 1st, 2nd, or 3rd level consumer ex. bears, humans iv. SCAVENGERS-- * organisms that eat only other animals after they are already killed * usually a 2nd or 3rd level consumer ex. vultures, hyenas v. DECOMPOSERS-- * organisms that live on DEAD matter * also called saprophytes ex. include heterotrophic plants, fungi, and bacteria
FOOD CHAIN- * always starts with producers * shows the pathway of energy from one organism to the next in a direct line of organisms.
FOOD WEB * shows the interactions and interconnections among the different food chains of a community.
Food web in an ecosystem
2) Symbiotic Relationships:
* an interaction among different species in an ecosystem that where they live in a close association with each other * called SYMBIOSIS; at least one member of the association benefits (gains) by the association
a) MUTUALISM (+ , +) * a symbiotic relationship in which both organisms BENEFIT ex. nitrogen fixing bacteria that live in nodes (lumps) on the roots of certain plants (legumes)...the bacteria have a nice place to live (+), and the plants benefit from getting the nitrogen they need from the bacteria (+)
b) COMMENSALISM (+ , 0) * a symbiotic relationship where one organism benefits (+) and the other organism is not harmed (0) ex. the remora (a small fish) attaches itself to the underside of a shark...when the shark feeds, the remora disconnects and eats scraps that are left over (+) ... the shark is not affected (0)
c) PARASITISM (+ , -) * a symbiotic relationship where one organism, the parasite, benefits (+), while the other organism, the host, is harmed (-) ex. athlete's foot, a fungus, grows on human feet for nutrients (+), while the human doesn't like it (-); tapeworms (+) in humans (-); heartworms (+) in dogs (-) d) PREDATOR-PREY (+, -) * a symbiotic relationship where one organism eats another! ex. predator--lions (+), prey--gazelles (-)
ENERGY AND MATERIAL CYCLES IN AN ECOSYSTEM
in order for an ecosystem to be self-sustaining, it must have a continuous flow of energy and be able to recycle materials
A) energy pyramid: * at each step of the food web, energy is transferred to the next higher level * sun--->plant-->rabbit--->snake--->hawk * this energy transfer is NOT EFFICIENT! * only 10% of the energy is passed to the next generation to be used; most energy is lost in maintaining homeostasis and as the production of heat * the amount of usable energy decreases at each higher feeding level
B) biomass pyramid: * the amount of organic matter in an ecosystem is its BIOMASS (producers make biomass) * the biomass pyramid shows the total amount of biomass at each feeding level * the higher the level, the less the biomass...which is because there is less energy at this level
C) material cycles 1) CARBON-OXYGEN CYCLE * involves the processes of photosynthesis (uses CO2 and produces O2) and respiration (uses O2 and produces CO2)
WATER CYCLE * involves the processes of photosynthesis, transpiration (movement of water through a plant), evaporation and condensation, respiration, and excretion
3) NITROGEN CYCLE * involves decomposers and other soil bacteria which break down and convert nitrogenous wastes and the remains of dead organisms into material that is usable by autotrophs (nitrates)
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