Chapter 3: The Biosphere What is ecology?

Ecology Ecology – the study of interactions among organisms and between organisms and their environment Interdependence – dependence of every form of life on other living things and natural resources (air, water, land) in its environment

Levels of Organization Biosphere – largest, portions of planet where life exists (land, H2O, air) 8 km above to 11 km below Biome – group of ecosystems with same climate (temp. and rainfall) Ecosystem – collection of all organisms in a particular place together with the abiotic (physical) environment.

Levels of Organization Community – groups of different populations that live together in a defined area. Population – groups of individuals of same species in same area. Species – group of organisms so similar that they can mate and produce fertile offspring.

Levels of Organization

Biotic and Abiotic Factors Biotic – living Plants, Animals ,Mold, Fungi, Bacteria, Protist Abiotic – Nonliving Sunlight, soil, wind, water, temperature Habitat – the area where an organism lives; includes both biotic and abiotic factors.

Ecological Methods Observation – 1st step to designing an experiment Experiment – test hypotheses; imitate & manipulate Modeling – make models based on observation & experiment Helps make future predictions

3.2 ENERGY FLOW (Autotrophs and Heterotrophs) One of the most important factors to determine capacity to sustain life is Energy Flow

Autotrophs (producers) Can trap light energy to produce food (organic molecules) Plants Some protists Some bacteria Photosynthesis – captures solar energy and converts it to chemical energy 6CO2 + 6H2O C6H12O6 + 6O2 Chemosynthesis – Chemical energy used to produce carbohydrates SUN

Heterotrophs (consumers) Can’t trap energy directly; must acquire it from other organisms Herbivores – plants Carnivores – animals Omnivores – both Detritivores – remains of dead plants & animals Decomposers – break down organic matter

3.2 Energy Flow in Ecosystems Food Chains and Food Webs

Food Chains and Food Webs SUN Autotrophs Heterotroph Food Chain – energy trapped by producers passed on when organisms eat and are eaten Food Web – relationship more complex than a chain

Trophic Levels and Ecological Pyramids Trophic Levels – each step in a food chain/web Ex: producers, then consumers Ecological Pyramids – shows relative amount of energy at each level (10% rule) Biomass – total amount of living tissue within a trophic level

Trophic Levels and Ecological Pyramids

3.4 Cycles of Matter *Recycle Matter*

Carbon Cycle Photosynthesis – uses CO2 from atmosphere Happens in the CHLOROPLAST 6CO2 + 6H2O C6H12O6 + 6O2 Respiration – returns CO2 to atmosphere Happens in the MITOCHONDRIA C6H12O6 + O2 H2O + CO2

Carbon Cycle

The Carbon Cycle Volcanoes, respiration, fossil fuels, and decomposition add CO2 to atmosphere. Plants take CO2 and make carbohydrates Plants are eaten by animals and carbohydrates are passed through the food chain. As the animal breathes and eventually dies and decomposes CO2 is return to atmosphere. Decomposing Fox

Water Cycle

Water Cycle Water enters the atmosphere by: Evaporation – water changes from a liquid to a gas Transpiration – Evaporation through leaves As water rises it cools condenses into tiny droplets that form clouds. Droplets return to Earth as precipitation. Water enters the rivers, ground water, ocean or plant roots to restart cycle. Making Clouds

Nitrogen Cycle

Nitrogen Cycle Nitrogen gas makes up 78% of atmosphere Nitrogen Fixation: bacteria take nitrogen gases and turn it into ammonia, nitrite, and nitrate. Plants and animals use nitrate to make amino acids. Animal dies and decomposes returning nitrates to the soil. Denitrification: other bacteria convert nitrates into nitrogen gas. Fertilizer Runoff

Nutrient Limitation Primary Productivity – the rate at which organic molecules are created by producers If nutrients are in short supply, they are called LIMITING NUTRIENTS Ex: Nitrogen is often limiting in water; if there is suddenly as input of N (fertilizer runoff), organisms can grow rapidly (Algal Bloom)

Human Impacts Look at each of the cycles in your notes. In each cycle there is at least one to two ways that imbalance can occur. Identify the sources of imbalance and in particular how human activities upset the cycles. Explain how this imbalance impacts the cycle and potential ecological problems that could result. You should identify at least one imbalance for each cycle (water, nitrogen, and carbon)? Each table group will turn in one paper with your answers.