Chapter 3

Ecology= study of living organisms and how they interact with one another as well as with the non-living world Abiotic= Non-living factors that support an ecosystem (air, water, soil) Biotic = living factor that support an ecosystem (anything that contains cells)\

Earth’s Life Support Systems There are 3 basic processes that make it possible for life not only to exist, but to flourish One way flow of energy from the sun Cycling of nutrients A consistent force of gravity

One Way Flow of Energy from the Sun Energy from sun arrives at the earth in the form of solar radiation Half of solar radiation is in the form visible light 40 % arrives as infrared radiation that is largely responsible for planetary heating The rest of the energy helps to keep the earth warm

Solar energy flowing through the biosphere warms the atmosphere, evaporates and recycles water, generates winds and supports plant growth.

Cycling of Nutrients The Earth acts as a closed system for matter. There is a fixed supply of nutrients on the planet that must be continually recycled to support life

Falling leaves and twigs Soluble mineral nutrients Oxygen (O2) Sun Producer Carbon dioxide (CO2) Secondary consumer (fox) Primary consumer (rabbit) Precipitation Producers Falling leaves and twigs Figure 3.10 Natural capital: major components of an ecosystem in a field. Soil decomposers Water Soluble mineral nutrients Fig. 3-10, p. 57

4 major systems that regulate and support life in biosphere Atmosphere= Most of its mass exists within the first two layers Troposphere= layer where weather occurs 78 % nitrogen, 21 % oxygen Also includes our greenhouse gases that are responsible for warming the surface of the earth

Greenhouse gases Gases include= water vapor, carbon dioxide, and methane Gases absorb radiation emitted by earth’s surface Molecules gain kinetic energy and vibrate they release even longer wavelength infrared radiation which warms the earth’s surface

Stratosphere= contains our ozone layer Responsible for filtering out 95 % of the harmful ultraviolet light.

Hydrosphere Consists of all the water available on the planet. Water is found in many various forms on the planet Liquid= surface and underground Ice= polar ice, permafrost, and icebergs Water vapor

Geosphere Consists of earth’s crust, mantle, and core Crust and mantle contain the soil and rock system that house nonrenewable fossil fuels and minerals

Ecosystem Structure Each organism can only live within a specific range of tolerance Physical & Chemical variations that exist within their environment Range of tolerance may vary Optimum Range= range in which growth of a population is maximized Certain abiotic factors like water, temperature, dissolved oxygen, or salinity will influence what the optimum range will be for a species.

Optimum Range

Energy flow in ecosystems Organisms in the ecosystems are organized into a hierarchy of feeding orders or (trophic levels) Trophic levels are assigned based on the organisms method for acquiring energy and nutrients from the ecosystem Energy passes from one trophic level to the next and organisms are either producing energy for the ecosystem or consuming energy from it.

Producers These organisms are self feeders, or often referred to as primary producers (autotrophs) Acquire nutrients by converting compounds or energy from their environment They represent the first trophic level in the ecosystem Most of producers acquire nutrients by photosynthesis

On land dominant producers are = green plants Ocean= phytoplankton (single celled algae) There are communities that thrive without the sun for energy Hydrothermal vent communities

Bacteria are the producers Convert sulfur compounds escaping from vents into organic compounds for consumers Chemosynthesis

Consumers: Eating and Recycling to Survive Consumers (heterotrophs) get their food by eating or breaking down all or parts of other organisms or their remains. Herbivores Primary consumers that eat producers Carnivores Primary consumers eat primary consumers Third and higher level consumers: carnivores that eat carnivores. Omnivores Feed on both plant and animals. All use the process of cellular respiration

Types of Consumers

Decomposers & Detrivores Bacteria & Fungi Breakdown organic compounds without the use of oxygen known as anaerobic respiration or fermentation

Decomposers recycle organic material that support the growth and development of primary producers Detritivores= Insects or other scavengers that feed on wastes or dead bodies