Systems A system is a collection of related parts that interact in some organized way. Materials, energy and information that enter the system from outside are Inputs. Materials, energy, and information that leave are outputs

A system can be: made up of many sub-systems be part of a larger system. E.g. An automobile is a system made up many smaller systems like the engine system, brake system and a fuel system. Each of these systems are connected to one or more other systems. A change in one system will affect the others.

Earth Systems Earth-Universe Biosphere Cryosphere Atmosphere Hydrosphere Solid Earth

Biosphere: This is the area occupied by living organisms. In resent years this has expanded with the finding of life deep underground. The biosphere has played a major role in the shaping of our planet and still has a major impact on climate, erosion and weather patterns.

Ecology What is ecology? (oikos = house or place to life; logos = study of Ecology is the study of the way living things interact with each other and their physical surroundings. It looks at the ways an organism is molded by its surroundings, how they make use of these surroundings, and how the area is altered by the presence and activities of organisms. These interactions involve energy and matter, which must flow through the organism if it is to stay alive.

An is any form of life. Organisms can be classified into - groups of organisms that resemble one another in appearance, behavior, chemistry, and genetic code. They are the same species if they can reproduce sexually to produce live, fertile offspring. A consists of all the members of the same species living in a specific area at the same time. The place where a population lives is known as its . Populations of all the different species occupying and interacting in a particular place make up a . organism species population habitat community

An is a community of different species interacting with one another and their no-living environment of matter and energy. All the Earth’s ecosystems make up what is called the or Climate is the main factor that determines whether a given species will thrive in an area. Biologists have divided the terrestrial (land) portion of the biosphere into . These are large regions with a distinct climate and specific life forms. E.g. Desert, grassland. Each biome may have many ecosystems with communities adapted to the changes in soil, climate and other factors throughout the biome. The marine and freshwater portions of the biosphere are divided into aquatic life zones. ecosystem ecosphere biosphere biomes

Biodiversity is the genetic diversity, species diversity and ecological diversity that are so important to life on this planet. It is the result of adaptations that have evolved over billions of years due to environmental changes in the Earth’s past.

Energy flow in Ecosystems

Trophic Levels tertiary consumer secondary consumer Primary consumer Producer

Energy and the Food Chain If 10% of the energy can be transfered from one trophic level to the one above it, each trophic level must have 10x the energy as the one above it. The number of trophic levels depends upon the primary producers

Primary Producer plant/ algae autotrophs 99% Primary consumer herbivores heterotrophs Secondary consumer primary carnivore Tertiary consumer top carnivore Usually no more than 5 links in a food chain. Why? Detritivores, scavengers, and decomposers Detritivores: consume litter, debris, and dung Scavengers: clean-up dead carcasses Decomposers: microorganisms that complete final breakdown of organic matter

Energy Pyramid

Food Chain

Food Web

There is limit to the number of trophic levels in an ecosystem - maximum 3 or 4 because of this energy loss - a consequence of the 2nd law of thermodynamics. For example it takes a large population of zebras and wildebeests to support a small population of lions (1000 to 1!!!) Humans eat steak and hamburger at a great cost in energy.

Nutrient Cycles Again, nutrients (the basic chemical building blocks of all life) are recycled in a living system. The key nutrients are Carbon, Hydrogen, Oxygen, Nitrogen and Phosphorus. These constitute 95% of all living matter.

Carbon Cycle

Nitrogen Cycle

Phosphorus Cycle

Hydrogen and Oxygen (Water) Cycle

Click the image to play the video segment. Cycles in Nature Click the image to play the video segment. Video