Ecology, ecosystems and food webs Chapter 3 Ecology, ecosystems and food webs

Ecology Groupings Organism – single living thing Species – several of same type of organism Population – several of same species interacting Community – several populations interacting in a certain area Ecosystem – community interacting with each other and the environment

Biosphere Biosphere Ecosystems Communities Populations Organisms Fig. 4.2, p. 72

Parts of the planet Planet as a solid – inner/outer core, mantle, crust Lithosphere is the crust and asthenosphere Hydrosphere is the water regions Atmosphere is the 5 layers of air Troposphere (11 miles) 78% N2, 21% O2, 1% Ar Stratosphere (11 – 30 mi) O3, blocks UV

core Mantle Crust Biosphere Atmosphere Hydrosphere Lithosphere Vegetation and animals Soil Crust Rock core Lithosphere Mantle Crust (soil and rock) Crust Biosphere (Living and dead organisms) Atmosphere (air) Hydrosphere (water) Lithosphere (crust, top of upper mantle) Fig. 4.6, p. 74

Incoming solar energy 34% reflected by clouds 42% heats earth and atmosphere 23% evaporates water 1% creates wind <1% photosynthesis

Solar radiation Energy in = Energy out Earth Reflected by atmosphere (34%) UV radiation Radiated by atmosphere as heat (66%) Lower Stratosphere (ozone layer) Visible light Greenhouse effect Absorbed by ozone Troposphere Heat Absorbed by the earth Heat radiated by the earth Earth Fig. 4.8, p. 75

Greenhouse effect Solar energy (light) that reaches the earth is converted into short wave radiation (heat) infrared. This infrared radiation has a hard time passing through the gasses in our atmosphere thereby trapping heat and keep the planet about 30 degrees (Celsius) warmer Important gasses – H2O, CO2, CH4, N2O, O3

Biomes Large regions characterized by a distinct climate and adapted vegetation Remember climate is weather patterns over a long period of time, usually several decades Because certain plants are adapted to a particular biome, so too are certain animals which depend on those plants for food

Biomes There are not distinct boundaries between biomes, rather there are ecotones. An ecotone is a blending of biomes and generally carries a greater quantity and variety of species

Components of Ecosystems Abiotic – nonliving Sunlight Temperature Precipitation Wind Latitude Soil Salinity (aquatic)

Terrestrial Ecosystems Aquatic Life Zones • Sunlight • Temperature • Precipitation • Wind • Latitude (distance from equator) • Altitude (distance above sea level) • Fire frequency • Soil • Light penetration • Water currents • Dissolved nutrient concentrations (especially N and P) • Suspended solids Fig. 4.13, p. 79

Components of Ecosystems Range of tolerance – how much of an abiotic factor can an organism withstand Limiting factor – the one factor that is holding back a population from reaching its biotic potential (max growth) Important limiting factors in aquatic systems Dissolved oxygen, salinity, temperature, light, nutrients, etc.

Abundance of organisms Population size Low High Temperature Zone of intolerance physiological stress Optimum range No organisms Few Lower limit of tolerance Abundance of organisms Upper limit Fig. 4.14, p. 79

Food webs (chains) Producers (autotrophs) plants Using chemosynthesis (some bacteria) Using photosynthesis (plants) 6 CO2 + 6 H2O + sun (yields) C6H12O6 + 6 O2 Plants convert only about 1-5% of the light they absorb into chemical energy, and absorb only about half the light that strikes them

Herbivores Primary consumers – eat producers (oh the humanity) Teeth designed for grinding

Carnivores Secondary consumers – meat eaters only Feed on primary consumers (herbivores) Teeth designed for tearing (large canines and sharp molars) cats for example

Omnivore Tertiary consumer – eat anything, feeding on other carnivores makes them tertiary We are omnivores, just look at our teeth, but we really should eat more veggies and less meat (in my opinion)

The other consumers Scavengers – feed on dead organism they did not kill, but found dead Detritivores – feed on parts of dead organisms Decomposers – bacteria and fungi, break down small detritus into raw nutrients Biodegradable means can be broken down by decomposers

Aerobic respiration Normal cellular process for most organisms Convert sugar and oxygen into energy leaving water and carbon dioxide as products C6H12O6 + 6O2 yields 6 CO2 + 6 H2O + energy

Anaerobic Respiration Also called fermentation The breakdown of glucose without oxygen present Produces: methane, ethyl alcohol, acetic acid, and hydrogen sulfide

Food chains Trophic level – feeding level First trophic level – plants Second trophic level – primary consumers Third trophic level – secondary consumers Fourth trophic level – tertiary consumers Remember heat is lost in every transfer between trophic levels

Pyramid of energy flow Only about 10% of the usable energy transfers between trophic levels (5-20%) For this reason we must rely on the transfer of solar energy from producers to consumers This is why it is so important to care for the plants of this planet

Biomass Organic matter produced by producers (photosynthesis) Total dry weight of organic matter in plants and animals in an ecosystem

Biomass Productivity Highest net biomass productivity per square meter is in wetlands, estuaries, and rain forests Highest gross (but lowest per sq. meter) is the open ocean. Because of its size it has a lot of algae that add up to high productivity

Nutrient cycles Atmospheric – Carbon and Nitrogen Sedimentary – Phosphorus and Sulfur Hydrologic cycle – water cycle helps to transport many nutrients

Hydrologic cycle Evaporation/transpiration Condensation Precipitation Infiltration Percolation Runoff Powered by the Sun and gravity

Carbon cycle Atmosphere Photosynthesis/respiration Fossil fuels Limestone Dissolved in the ocean

Nitrogen cycle (very important) Nitrogen in the air Nitrogen fixation by bacteria to ammonia Nitrification by bacteria to nitrite NO2- Nitrification by bacteria to nitrate NO3- Assimilation by plants Ammonification of dead organic material by bacteria and fungi Denitrification of nitrate by bacteria back to atmosphere

Phosphorus cycle Very slow Limited amount found in the soil Limiting factor for plant growth Excess causes prolific plant growth (algal blooms in water) We add phosphates to detergents/fertilizers

Sulfur cycle Passed as sulfates (salts) mostly Hydrogen sulfide (swamps/volcanoes) Sulfur dioxide (volcanoes) Ammonium sulfate (sea spray) Reacts in atmosphere to create hydrogen sulfate (H2SO4) sulfuric acid (acid rain)

Ecosystem services Waste removal pest control Soil formation biodiversity Water purification matter resources Air purification aesthetic pleasure Climate control Recycling vital chemicals Renewable energy

Achieve sustainability Use renewable energy (especially solar) Recycle chemical matter REALIZE WE LIVE IN A CLOSED SYSTEM! The END!!!