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Explore the study of relationships between organisms and their environment, including the levels of organization in ecosystems and the flow of energy. Learn about producers, consumers, food chains, food webs, and energy pyramids.
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Ecology • the study of the relationships between organisms and their physical environment
Ecosystem ABIOTIC FACTORS BIOTIC FACTORS Consists of BOTH BIOTIC AND ABIOTIC FACTORS
Levels of Organization • Species- group of individuals so similar that they can reproduce together and produce fertile offspring. • Population- group of organisms of the same species living in the same area. • Community- groups of populations living together in a defined area.
Ecosystem- collection of all the organisms that live together in a particular place, together with their non-living environment. • All ecosystems need a constant source of energy and recycling of materials. • Energy does NOT get recycled, it is continuously added.
Biome- group of ecosystems with the same climate. • Biosphere- highest level of organization- portion of the earth in which life exists of numerous complex ecosystems.
Ex. Earth Ex. Desert, Tundra Ex. African Plains, Coral Reefs Ex. All living things in African plains Ex. All the giraffes Ex. One giraffe
Requirements of All Ecosystems • Energy must be constantly added (usually from the sun). Energy cannot be recycled!
Energy Flow • Sunlight is the main energy source.
1. Producers (Autotrophs) • Plants, algae and certain bacteria can capture energy from sunlight and use it to make food. • More of them than any other organism in an ecosystem! • Ex. Trees, algae, grass, phytoplankton
2. Consumers (Heterotrophs) • Must obtain their energy from eating other organisms.
Types of Consumers Herbivores Feed only on autotrophs like plants, leaves, grass, or seeds
CarnivoresFeed only on other animals • Predator: kill & eat their prey • Prey: killed by predators • Scavengers: feed on dead animals they have not killed themselves.
Omnivores Feed on producers as well as consumers (plants and animals)
Detrivores/Decomposers • obtain nutrients from “detritus” - the remains of dead or decaying organisms • Recycle nutrients back into the earth
ENERGY FLOW IN AN ECOSYSTEM The flow of energy between producers and consumers can be organized in a number of ways… • Food Chain • Food Web • Energy Pyramid
Food Chains • Diagram showing one chain of energy existing between organisms in an ecosystem • Arrows point in the direction of energy flow! • Ex.
Food Webs The mouse population would most likely decrease if there were (1) an increase in the frog and tree populations(2) a decrease in the snake and hawk populations(3) an increase in the number of decomposers in the area (4) a decrease in the amount of available sunlight Identify two producers in this food web. • All of the interconnected food chains in an ecosystem
Which organisms feed on both producers and decomposers? (1) amphipods (2) crayfish (3) catfish (4) protozoa Which organism is a producer in this food web? (1) algae (2) amphipod (3) snail (4) catfish What would happen to the diving beetle population if there were fewer snails? Justify your response.
Energy Pyramids -Part of the energy that is stored in one trophic (feeding) level is passed onto the next -organisms use much of the energy for themselves and some remaining energy is released into the environment. A food pyramid is represented by the diagram. Which statement best describes one of the levels of this pyramid? (1.) The organisms in level B obtain food directly from level A. (2.) Level D contains the greatest number of heterotrophs in the pyramid. (3.) level C contains the largest group of consumers in the pyramid. (4.) Level A contains the largest producers in the pyramid.The secondary consumers in this pyramid would be found at level (1.) A (2.) B (3.) C (4.) D
Which organisms would contain the greatest amount of available energy? (1.) rabbits and deer (2.) grasses and shrubs (3.) hawks (4.) lice The primary consumers include (1.) insects and seed-eating birds (2.) rabbits and snakes (3.) rats and frogs (4.) spiders and coyotes Which group of organisms is missing from this food web? (1.) decomposers (2.) omnivores (3.) producers (4.) heterotrophs
Information concerning nests built in the same tree by 2 different bird species over a 10-year period is shown in the table below. Which inference best describes these 2 bird species? 1)They most likely do not compete for nesting sites because they occupy different niches 2) They do not compete for nesting sites because they have the same reproductive behavior 3) They compete for nesting sites because they build the same type of nest 4) They compete for nesting sites because they nest in the same tree at the same time
Controls on Population Growth • Limiting Factors • Factors that cause the growth of a population to decrease. • Ex: competition, predation, parasitism and disease, climate extremes, human disturbances.
Carrying Capacity • Occurs when the environment can support its maximum number of individuals.
Competition • When populations become crowded , organisms must struggle and compete with one another for food, water, space and other resources. • Over time, species may evolve to occupy separate niches. (role the organism plays in its environment)
Predation • Controls populations in an oscillating manner. • Ex- wolf and moose populations
Parasitism and Disease • Parasites take nourishment at the expense of their host, often weakening them greatly or causing death.
Symbiotic Relationships Organisms living in close association with each other • Mutualism (+/+) both organisms benefit from their association with each other. Ex. Cleaning associations
Commensalism (+/0) one organism benefits, but the other is NOT affected at all Ex. Barnacles on a whale, anemone and clown fish
Parasitism (+/-) one organism benefits (parasite) while the other is harmed (host) Ex. Athlete’s Foot fungus and humans! Ex. Ticks on deer/dogs symbiosis video
Ecological Succession • The series of changes by which one habitat changes into another. • In the process of ecological succession, each community causes modifications to its environment.
Steps: • Lichens- as they grow, they help break up the rocks. When they die, they add organic material to help form soil for plants to grow in. “Pioneer organism” • Grasses • Shrubs and bushes • Trees • Climax community
Over a period of many years, these gradual changes may result in the formation of a stable ecosystem. • Climax community- plants and animals exist in balance with each other and the environment. • Biodiversity- presence of a wide range of different species of organisms living and interacting with one another and their non living environment.
An ecosystem, such as an aquarium, is self-sustaining if it involves the interaction between organisms, a flow of energy, and the presence of 1. equal numbers of plants and animals 2. more animals than plants 3. materials cycles 4. pioneer organisms Brainpop
Material Cycles • Water Cycle • Carbon Oxygen Cycle • Nitrogen Cycle
Material Cycles • Although ENERGY must be CONSTANTLY ADDED by the sun, many materials are used over and over again by organisms in a food web • Carbon: components of living organisms (carbs, lipids, proteins), also CO2 • Oxygen: needed for cell respiration, produced by plants • Water: used for transport within all organisms • Nitrogen: important part of proteins (amino acids), released as waste from dead organisms
Involves the evaporation of water from the surface of the earth and the condensation of rain, dew, snow, etc. • Water vapor is also given off by transpiration in plants and as a waste product of respiration. • During evaporation- water is changed into water vapor and during condensation, water vapor is changed back into water.
Involves the processes of cellular respiration and photosynthesis. • During photosynthesis- water and carbon dioxide are used to produce carbohydrates and oxygen is released as a by-product. • During respiration, oxygen is used and carbon dioxide and water are released.
Nitrogenous wastes and the remains of dead organisms are converted by decomposers and soil bacteria into compounds that can be used by autotrophs.