Intro to Ecosystems and Ecology Monday, November 13th, 2017

These notes to should to cement the ideas you read about in Module 14 These notes to should to cement the ideas you read about in Module 14. Fill in your notes handout as you go along. You will not be able to access/watch the videos in class, but it is strongly recommended you go home and watch the videos that are found throughout the powerpoint. Don’t worry, there’s still puns  Miss Scott

This lecture will help you understand Feeding relationships Food Webs Trophic levels Energy flow Productivity ….. Ecology & the ecosystem

Deforestation in Haiti Deforestation is cutting down trees. People cut down trees for firewood – use to make charcoal. Deforestation disrupts ecosystem services Land is susceptible to erosion Rainwater runs down mountainside – lose topsoil (important for forest growth) Oversaturation of soil causes mudslides US Agency for International Development planted mango trees because they provide almost $150 annually – people won’t cut them down because they are more valuable growing/producing mangos

All the parts of an ecosystem are interrelated. Biotic (living): trees, animals, insects, bacteria & abiotic (nonliving): sunlight, temperature, soil, water, pH, nutrients Highly dependent on climate. Boundaries are important because they help distinguish ecosystems. Knowing boundaries help us identify components and trace energy/matter cycles.

Ecosystems interact with each other by exchanging energy and matter. Energy flows through ecosystems. Solar energy enters through plants Spreads to producers (autotrophs) & consumers (heterotrophs). 2nd law of thermodynamics says energy conversion is not 100% efficient –not all energy is transferred to consumer, some is lost as heat.

Nearly all energy that powers ecosystems is solar energy, a form of kinetic energy. Producers (autotrophs) use sun’s energy to produce usable forms of energy through photosynthesis. Copy the diagram/equation for photosynthesis.

Cellular respiration = unlocks chemical energy stored in food sources (like glucose). All organisms perform cellular respiration.

Photosynthesis & Cell Resp Review Video You don’t need to know all the crazy details about fermentation, etc. but you should know the chemical equations for both and how they relate to the Carbon Cycle specifically.

Heterotrophs = consumers Primary consumers – eat producers Secondary consumers – eat primary consumers tertiary consumers – eat secondary consumers Scavengers: carnivores that eat dead animals Detritivores: break down detritus (dead tissue/waste) into smaller particles – responsible for cycling matter Decomposers: Break down the particles from detritivores

Trophic levels: organism’s role/place/order in the food chain Food chain vs food web: Food chain: what eats what – producers to tertiary consumers Food web: a bunch of food chains interacting

The amount of energy available determines how much life can be supported. Gross Primary Productivity (GPP): total amount of solar energy captured by producers Net Primary Productivity (NPP): energy captured minus energy respired NPP = GPP – respiration by producers Determine the rate of photosynthesis by: measuring the compounds that participate in the reaction (example: CO2) NPP efficiency ranges from 25% to 50% of GPP. *measure NPP is a useful way to compare ecosystem productivity

The net primary productivity of an ecosystem is 10 kg C/m2/year The net primary productivity of an ecosystem is 10 kg C/m2/year. The energy needed by the producers for their own respiration is 1.5 kg C/m2/year. What is the GPP of the ecosystem?

Energy flow in ecosystems

Biomass: total mass of all living matter in an area Rate of production determined by NPP Standing crop: amount of biomass present at a particular time Ecological efficiency: Proportion of consumed energy that can be passed up the trophic levels (5-20%) What is the 10% Rule? Only 10% of biomass can be passed up to the next level. For example, producers get 100J of energy, primary consumers would only get 10J.

Trophic pyramid: diagram to represent the distribution of biomass (using the 10% rule)

Biomass pyramid is measure of the total dry mass of organisms in a given area while the Pyramid of numbers shows the number of Individual organism at each trophic level in an ecosystem Energy Pyramid: Diagram that compares energy used by producer primary consumers and other trophic levels