2.1 Ecology & Ecosystem Structure

Transcription

1 2.1 Ecology & Ecosystem Structure Learning Goals: 1. Explain how biotic and abiotic factors influence 2. Explain how the flow of energy through ecosystems obeys the 2nd law of thermodynamics. 3. Calculate net primary productivity. A. Ecology study of living organisms and how they interact with one another and with the nonliving world. 1. Biotic factors any living component that affects another organism, including organisms themselves and the food that the organism consumes a. Cell basic unit of life b. Prokaryotes and Eukaryotes c. Unicellular and multicellular 2. Abiotic factors - non-living chemical and physical parts of the environment that affect living organisms and the functioning of ecosystems 3. Biosphere part of the earth where living organisms interact. A. Ecology 4. Population a group of individuals of the same species that live in the same place at the same time. 5. Community all the populations of different species that lice in one place at one time. 6. Ecosystem a community interacting with the abiotic factors in their environment. 1

2 B. Earth s Life Support Processes 1. Energy Flow energy from the sun flows one-way through the biosphere; not recycled because of 2 nd law of thermodynamics a. Only 0.1% of solar radiation is captured by primary producers b. Rest is used warm earth s surface causing atmospheric circulation and evaporation of water. 2. Nutrient Cycling nutrients cycle because earth is a closed system 3. Gravity holds the atmosphere and facilitates the flow of nutrients and water C. Earth s Life Support Systems 1. Atmosphere a. Troposphere bottom layer where weather occurs (17km) b. 78% nitrogen, 21% oxygen, 1% mostly argon and greenhouse gases (water vapor, CO 2, methane) c. Greenhouse Effect - process by which thermal radiation from Earth s surface is absorbed by atmospheric greenhouse gases, warming the atmosphere. d. Ozone layer Layer of O 3 in the stratosphere that filters 95% of UV radiation. C. Earth s Life Support Systems 2. Hydrosphere consists of all the water on our planet. a. Liquid surface and groundwater b. Solid polar ice, permafrost, and icebergs c. Gas water vapor 3. Geosphere consists of the crust, mantle, and core. 4. Biosphere portion of planet that supports life a. Biomes portion of the terrestrial biosphere that have distinct climates that dictate their unique flora and fauna. b. Marine zones salt water biomes c. Aquatic zones freshwater biomes 2

3 A. Range of Tolerance range of abiotic and biotic factors that certain organism can tolerate in an ecosystem 1. Optimum Range Allows for the greatest growth of a population in an ecosystem. 2. Limiting Factors Limit the population in a given ecosystem 1. Trophic Levels feeding orders a. Producers acquire nutrients by converting compounds or energy from their environment (autotrophs) i. Photosynthesis converts solar energy into carbohydrates ii. Chemosynthesis converts chemical compounds (H 2 S) into organic compounds. b. Consumers cannot produce their own energy and rely on cellular respiration to break down organic compounds that are consumed (heterotrophs) i. Primary consumers (herbivores) eat only producers ii. Secondary consumers (carnivores and omnivores) feed on other consumers iii. Tertiary consumers predators at the top of food chain iv. Detritovores feed on detritus (parts of dead organisms and fragments of waste) v. Decomposers bacteria and fungi that recycle organic material from dead organisms 3

4 2. Food Chain shows the movement of energy from one trophic level to the next 3. Food Web shows the more complex interrelationships of energy flow within a diverse community C. Productivity 1. Biomass dry weight of all organic matter contained in the organism; measure of energy available to the next trophic level. 2. Ecological Efficiency percent of usable chemical energy that is transferred as biomass from one trophic level to the next. a. 10% for most ecosystems (on average) b. 90% is lost as heat (2 nd law of thermodynamics) C. Productivity 3. Gross Primary Productivity rate at which producers convert solar energy into chemical energy through photosynthesis 4. Net Primary Productivity accounts for the loss of biomass through respiration in autotrophs. 4

5 1. Explain how biotic and abiotic factors influence I can identify the unique biotic and abiotic factors present in biomes and aquatic life zones. I can explain how biotic and abiotic factors influence I can contrast biotic and abiotic factors. I can identify the five levels of ecological hierarchy. 2. Explain how the flow of energy through ecosystems obeys the 2nd law of thermodynamics. I can calculate the efficiency of energy transfer from one trophic level to the next. I can explain how the flow of energy through ecosystems obeys the 2 nd law of thermodynamics. I can identify trophic levels in a food web. I can identify trophic levels in a food chain. 3. Calculate net primary productivity. I can explain why all ecosystems depend on net primary productivity. I can calculate net primary productivity. I can contrast gross primary productivity and net primary productivity. I can define primary productivity. 5