ECOLOGY Chapter 3 - The Biosphere

What is Ecology? It is the scientific study of interaction among organisms and between organisms and their environment It is the scientific study of interaction among organisms and between organisms and their environment

What is the Biosphere? The biosphere is the combined portions of the entire planet where life exists. The biosphere is the combined portions of the entire planet where life exists.

Levels of Organization To understand relationships within the biosphere ecologists ask questions abut events and organisms that range in complexity from a single individual to the entire biosphere To understand relationships within the biosphere ecologists ask questions abut events and organisms that range in complexity from a single individual to the entire biosphere

Levels, cont. Species: a group of organisms so similar to one another that they can breed and produce fertile offspring. Species: a group of organisms so similar to one another that they can breed and produce fertile offspring. Populations: a group of individuals that belong to the same species and live in the same area. Populations: a group of individuals that belong to the same species and live in the same area. Communities: different populations that live together in a defined area. Communities: different populations that live together in a defined area.

Levels, cont. Ecosystems: all the organisms that live in a particular place, together with their nonliving or physical environment. Ecosystems: all the organisms that live in a particular place, together with their nonliving or physical environment. Biomes: a group of ecosystems that have the same climate and dominant communities. Biomes: a group of ecosystems that have the same climate and dominant communities.

Levels of Organization

Ecological Methods Scientists use three basic approaches to conduct ecological research. They are: Observing Observing Experimenting Experimenting Modeling Modeling

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Energy Flow in the Ecosystem Living systems need a constant input of energy. Living systems need a constant input of energy. Identify the main source of energy for life on Earth Identify the main source of energy for life on Earth Some types of organisms rely on the energy stored in inorganic chemical compounds Some types of organisms rely on the energy stored in inorganic chemical compounds

Energy Flow, cont. Autotrophs Autotrophs Organisms that use energy from the environment to make complex organic compounds Organisms that use energy from the environment to make complex organic compounds Also known as producers Also known as producers Two types Two types Photosynthesis Photosynthesis Chemosynthesis Chemosynthesis Heterotrophs Rely on other organisms for their energy and food supply. Also known as consumers Types: Herbivores Carnivores Detritivores Decomposers

Feeding Relationships Energy flows through the ecosystem in one direction. Energy flows through the ecosystem in one direction.

Food Chain

Food Web

What is a trophic level? Each step in a food chain or food web is a trophic level Each step in a food chain or food web is a trophic level Each trophic level depends on the level below it for energy Each trophic level depends on the level below it for energy

Ecological Pyramids Can be used to represent energy, matter or number of individuals at each trophic level Can be used to represent energy, matter or number of individuals at each trophic level Energy Pyramid: only 10% of the energy available at one trophic level makes it to the next level Energy Pyramid: only 10% of the energy available at one trophic level makes it to the next level

Pyramids, cont. Biomass Pyramid: represents all the living tissue (food) at each trophic level. Biomass Pyramid: represents all the living tissue (food) at each trophic level. Pyramid of Numbers: the number of individual organisms at each trophic level usually decrease as you go up the pyramid of numbers. Pyramid of Numbers: the number of individual organisms at each trophic level usually decrease as you go up the pyramid of numbers.

Cycles of Matter Unlike the one-way flow of energy, matter is recycled in the biosphere Unlike the one-way flow of energy, matter is recycled in the biosphere Elements, chemical compounds and other forms of matter are passed from one organism to another through biogeochemical cycles Elements, chemical compounds and other forms of matter are passed from one organism to another through biogeochemical cycles

Water cycle

Other biogeochemical cycles Carbon Cycle - carbon is especially important because it is the key ingredient in all living organisms. Carbon is found in oceans, the air, and certain types of rock Carbon Cycle - carbon is especially important because it is the key ingredient in all living organisms. Carbon is found in oceans, the air, and certain types of rock Nitrogen Cycle - All organisms require nitrogen to make amino acids which are used to build proteins Nitrogen Cycle - All organisms require nitrogen to make amino acids which are used to build proteins

Phosphorous Cycle- Unlike carbon nitrogen and oxygen, phosphorous does not enter the air, it remains mostly in rock, soil minerals, and ocean sediments Phosphorous Cycle- Unlike carbon nitrogen and oxygen, phosphorous does not enter the air, it remains mostly in rock, soil minerals, and ocean sediments Phosphorus is of great biological importance for molecules like DNA and RNA Phosphorus is of great biological importance for molecules like DNA and RNA

Productivity Primary Productivity: the rate at which organic matter is created by a producer. Primary Productivity: the rate at which organic matter is created by a producer. Controlled by the availability of nutrients in the environment Controlled by the availability of nutrients in the environment Limiting nutrient: the one nutrient that when in short supply, will limit the primary productivity of the ecosystem. Limiting nutrient: the one nutrient that when in short supply, will limit the primary productivity of the ecosystem. Algal Bloom Algal Bloom