Chapter 3. Ecology: Ecosystems. User: Mikala14/Wikimedia Commons/CC BY-SA3.0

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1 Chapter 3 Ecology: Ecosystems User: Mikala14/Wikimedia Commons/CC BY-SA3.0

2 Ecology = study of living things, their distribution, and their interactions with one another and their non-living environment. > connections in nature > can look at different levels (hierarchy or organization of life) Which of the following levels include interactions of organisms of the same species? Of different species? Of biotic and abiotic factors? a) Biosphere b) Ecosystem c) Communities d) Populations e) Organisms

3 Four Spheres 1. Atmopshere > Troposphere (17-48 km, most of planet's air) > Stratosphere (ozone) > Mesosphere > Thermosphere > Exosphere

4 Four Spheres 2. Hydrosphere: Water > liquid water > ice (polar ice, icebergs, permafrost) > water vapor

5 Four Spheres Lithosphere 3. Lithosphere: Solid parts of the earth (part of Geosphere) > crust and upper mantle > fossil fuels and minerals > soils

6 Four Spheres 1. Biosphere: All of the ecosystems > global ecosystem > all ecosystems are linked to one another > Example: terrestrial ecosystems are connected by flow of water and migrating animals. Biomes Divide terrestrial parts of biosphere into biomes. =Regions characterized by distinct climates and vegetation. Aquatic life zones Divide aquatic parts of the biosophere into aquatic life zones.

7 Four Spheres 1. Biosphere: All of the ecosystems > global ecosystem > all ecosystems are linked to one another > Example: terrestrial ecosystems are connected by flow of water and migrating animals. Biodiversity = diversity of living things found in the natural world. Genetic diversity Ecological diversity Species diversity Functional diversity 5 causes of species decline: HIPPO H-Habitat destruction/degradation I-invasive species P-Pollution P-human population growth O-over exploitation Why should we care? -Natural services -Natural resources

8 Four Spheres What are 3 ways that the various spheres interact?

9 3 factors required for life on Earth 1. Flow of high-quality energy 2. cycling of matter/nutrients 3. gravity Where does this "high-quality" energy come from?

10 Solar Energy Energy from sun reaches Earth as electromagnetic waves. Energy from Sun reaching Earth = Heat energy Earth reflects or radiates back into space. Why must this be true? Energy from sun is needed: to warm atmosphere for photosynthesis for cycling of matter (most directly, water) to drive climate and weather systems (distributes heat and freshwater--winds, ocean currents)

11 80% of energy that reaches earth warms troposphere and drives water cycle. 1% generates winds 0.1% photosynthesis

12 Greenhouse effect Warms the Earth's atmosphere. Solar radiation absorbed by Earth's surface and is reradiated out as infrared radiation (longer wavelength). Infrared radiation is absorbed by greenhouse gases (H 2 O, CO 2, CH 4, NO, O 3 ). Is the greenhouse effect "bad"? Why or why not?

13 Environmental Factors

14 Biotic v. Abiotic factors Think of a terrestrial ecosystem. List 3 biotic and 3 aboitic factors. Biotic Factors Abiotic Factors

15 Organisms are adapted to specific environmental factors. (i.e. temperature, precipitation) Optimum: level at which organisms grow or survive the most (can be a range) Range of Tolerance: entire range that allows any growth or survival Limits of tolerance: high/low ends of range of tolerance. Zones of stress: Between range of tolerance and optimum ecosystem.htm

16 Organisms are adapted to specific environmental factors. Limits a species' distribution or range: where we can find a species ecosystem.htm

17 Limiting Factor A factor that limits growth. Examples: Sunlight, specific nutrients, water, DOC, salinity. Limiting factor principle or law of limiting factors or Leibig's Law of the Minimum states that: too much or too little of any one abioitic factor can limit or prevent growth. Even if many different species occupy the same habitat, competition Habitat may v. Niche be slight or nonexistent. Why?

18 Energy Energy can be either categorized as: kinetic energy: energy in action or motion Examples: light, heat, physical motion, electrical current. potential energy: energy in storage Examples: chemical energy, a stretched rubber band. Remember the two laws of thermodynamics first law of thermodynamics: Energy cannot be created o second law of thermodynamics: when energy changes fr

19 Energy Flow and Matter Recycling In Ecosystems Trophic levels Producers (autotrophs)-photosynthesis Consumers (heterotrophs) Primary consumers ( ) Secondary consumers ( ) Tertiary consumers Omnivores Decomposers Detritivores

20 How do consumers use the energy stored in the foods they eat? Aerobic respiration Anaerobic respiration (fermentation)

21 On your paper, please draw a food chain involving a producer, a primary consumer, and a secondary consumer. Now add another secondary consumer, a decomposer, and a scavenger to create a food web.

22 Energy flows through the ecosystem as organisms eat and extract energy from the food. How does matter get recycled? What types of organisms are crucial to matter recycling?

23 Energy Flow and Matter Recycling In Ecosystems Trophic levels Producers (autotrophs)-photosynthesis Consumers (heterotrophs) Primary consumers ( ) Secondary consumers ( ) Tertiary consumers Omnivores Decomposers Detritivores *eats organic waste and parts of dead and/ or decaying organisms. Examples: Worms, termites Scavengers *eat dead organisms. Examples: Vultures, ants

24 Pyramids Graphical models of the quantitative difference between trophic levels. Different pyramids provide different information: Pyramid of numbers: Shows you the number of organisms at each trophic level. It usually takes a large number of producers (at the bottom) to feed the consumers. Exceptions: add_gateway_pre_2011/ greenworld/energyflowrev1.shtml add_gateway_pre_2011/ greenworld/energyflowrev1.shtml

25 Pyramids Pyramid of Biomass: Shows you the amount of biomass available at each trophic level. Biomass = dry mass of living organisms. (How would you calculate the biomass at each trophic level?) More accurate indication of how much energy is passed on at each trophic level. About 10% of the energy contained in one trophic level is incorporated into the bodies of the next trophic level. add_gateway_pre_2011/ greenworld/energyflowrev1.shtml add_gateway_pre_2011/ greenworld/energyflowrev1.shtml *In aquatic ecosystem, the pyramid of biomass is often inverted due to the high turnover rate of lower trophic level organisms.

26 Pyramids Pyramid of productivity: Shows the energy flow through trophic levels by showing production of biomass at each trophic level. Takes into account productivity over time. Illustrates ecological efficiency. Ecological efficiency: percentage of usable energy transferred as biomass from one trophic level to the next. What happens to the ~90% of the energy at each trophic level as it is transferred to the next trophic level? 1) Much of mass of preceding trophic level is not consumed. (Death, decay) 2) What is consumed is used as energy to fuel cells/tissues. (Respiration, lost as heat) 3) Some of what is consumed is undigested (feces). Only~ 10% of the energy is incorporated into the biomass of the next trophic level. (growth and reproduction)

27 GPP and NPP It is important to understand the rate at which an ecosystem's producers convert solar energy into chemical energy (as biomass). The total amount of productivity in a ecosystem is the gross primary productivity (GPP). Plants also respire (R). The net primary productivity (NPP)= GPP - R. This translates into how fast producers can provide food for consumers. *NPP limits the number of consumers.

28 Soil A thin covering over most land that is a mixture of eroded rock, mineral nutrients, decaying organic matter, water, air, and microorganisms (yeay!) Formation of soil: 1) weathering of bedrock -Physical -Chemical -Biological 2) Addition of decaying organic matter -Lichen -succession!

29 Ecological services provided by soil Retains and delivers nutrients and water for producers. Physical support for plants. Water storage. Water purification. Water percolates through soil. (Gravity!) Decompose and recycle biodegradable wastes. (Nutrient cycling) Removes CO2 from atmosphere, stores as organic C compounds.

30 Mature soils are arranged in soil horizons -Horizontal layers -Soil profile is a crosssection of horizons. User: Zwiadowca21/Wikimedia Commons/CC BY-SA3.0

31 Soil Profile User: Zwiadowca21/Wikimedia Commons/CC BY-SA3.0 O/A horizon contains most or organic matter. For "healthy" O/A horizon, want plant roots to anchor to store water and release as needed. *Contains microorganisms (bacteria fungi), earthworms, insects *decomposers -->break down organic compounds. Make inorganic compounds available to plants. B/C horizon contains most of inorganic matter

32 Other soil fun facts: Spaces/pores between particles contain air (nitrogen and oxygen) and water. Why do plants need oxygen? Infiltration = movement of water into the soil surface Percolation =downward movement of water through soil matrix. > leaching = infiltration dissolves minerals and organic matter, carries to lower layers Soil is a mixture of 3 kinds of particles: 1. clay (very small) --> sticky 2. silt (medium) --> smooth, like flour 3. sand (large) --> Gritty > Determines soil texture > Loam is ideal soil for plant growth. Mixture of all three--crumbly, spongy, with clumps of particles.

33 Biotic v. Abiotic Abiotic = SWATS Sunlight Water Air Temperature Soil*

34 Ecological footprint 1) environmental impact of individuals in a given country or area 2) amount of biologically productive land and water USED (your book uses needed) to supply an area with resources and to absorb the wastes and pollution produced by such resource use 3) amount of land and water area required to sustain your consumption pattern 4) measure of human demand on Earth's ecosystem *standardized measure of demand for natural capital

35 Biosphere -global ecosystem where all life is interconnected > ecosystem = community of different species interacting with one another and non-living environment. -all living things -all living things and factors needed to sustain life

36 Image References

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