4.1 Species , communities and ecosystems Topic 4: Ecology 4.1 Species , communities and ecosystems 4.2 Energy Flow I am the Lorax. I speak for the trees. I speak for the trees, for the trees have no tongues.

Ecology The study of relationships between living organisms and between organisms and their environment Components: abiotic~ nonliving chemical & physical factors biotic~ living factors

4.1 Species, communities and ecosystems Essential idea: The continued survival of living organisms including humans depends on sustainable communities. Discuss: what does it mean for a community to be sustainable? Discuss: Why is sustainability in human activities important and how can this be promoted?

What is a Species? Species: a group of organisms that can interbreed to produce fertile offspring Members of a species may be reproductively isolated in separate populations.

Levels of Organization Organism- an individual living thing Population~group of individuals of the same species who live in the same area at the same time. Community~a group of populations of different species that interact. Ecosystem~ a community and its abiotic environment Biosphere– the part of the earth contains all ecosystems

Methods of Nutrition Autotroph: an organism that synthesizes its organic molecules from simple inorganic nutrients in the abiotic environment. Ex. _____ Heterotroph: an organism that obtains organic molecules from other organisms. Consumer: feeds on living (or recently killed ) organisms by ingestion. Detritivores~ organism that ingests (and internally digests) non-living organic matter (detritus) ex. Earthworms, maggots. Saprotrophs -- or decomposers- organisms that live in or on non-living organic matter, secreting digestive enzymes and absorbing the resulting products of digestion. Notice: External Digestion Ex. bacteria and fungi.

Trophic Levels Trophic level~ the position that an organism occupies in a food chain - what it eats, and what eats it. Primary producers~ the trophic level that supports all others; autotrophs Primary consumers~ herbivores Secondary, tertiary… consumers~ carnivores Food chain~ trophic level food pathway

4.2 Energy Flow Essential idea: Ecosystems require a continuous supply of energy to fuel life processes and to replace energy lost as heat.

Most ecosystems rely on a supply of energy from ______. Light energy is converted to chemical energy in carbon compounds by photosynthesis. A solar prominence erupts in August 2012, as captured by SDO

Chemical energy in carbon compounds flows through food chains (and food webs) by means of feeding. Discuss: what are examples of carbon compounds that have chemical energy?

Nature of science Use theories to explain natural phenomena—the concept of energy flow explains the limited length of food chains. (2.2)

Energy released from carbon compounds by respiration is used in living organisms and converted to heat. Living organisms cannot convert heat to other forms of energy. Heat is lost from ecosystems. Energy losses between trophic levels restrict the length of food chains and the biomass of higher trophic levels.

Energy Pyramid Quantitative representation of energy flow Explain shape of the pyramid and be able to draw Energy transformations = never 100% efficient Roughly 10% passed to next level The rest is lost as heat, or not consumed/assimilated (IB Preferred units: kJ m-2 yr -1)

Biomass in terrestrial ecosystems diminishes with energy along food chains due to loss of carbon dioxide, water and other waste products, such as urea.

International-mindedness: The energetics of food chains is a factor in the efficiency of food production for the alleviation of world hunger. Discuss: What types of organisms should be used for food in order to feed the most people?

Flow of Energy vs. Cycling of Matter Energy enters and leaves ecosystems Nutrients = recycled (by saprotrophic bacteria and fungi) The supply of inorganic nutrients is finite and limited but is maintained by nutrient cycling. Ecosystems have the potential to be sustainable over long periods of time.

Skill: Setting up sealed mesocosms to try to establish sustainability Skill: Setting up sealed mesocosms to try to establish sustainability. (Practical 5) Mesocosm: small experimental areas set up as an ecological experiment. Guidance: • Mesocosms can be set up in open tanks, but sealed glass vessels are preferable because entry and exit of matter can be prevented but light can enter and heat can leave. Aquatic systems are likely to be more successful than terrestrial ones. • http://www.magzinr.com/user/D_Faure/mesocosm Many mesocosm ideas Succession in Pond water lab

Skill: Testing for association between two species using the chi-squared test with data obtained by quadrat sampling. Skill: Recognizing and interpreting statistical significance. To obtain data for the chi-squared test, an ecosystem should be chosen in which one or more factors affecting the distribution of the chosen species varies. Sampling should be based on random numbers. In each quadrat the presence or absence of the chosen species should be recorded. http://ibworld.me/Ecology.html

Take notes on this type of chi-squared test application from: http://ibworld.me/Ecology.html

End of IB stuff

Food Chain Be able to describe what is meant by a food chain, giving three examples, each with at least three linkages (four organisms) Hints: Arrows indicate direction of energy flow Include producer and consumers Name organisms at species or genus level: ex. Atlantic salmon (not “fish”) Use real examples from nature.

Food Chain Example

Food webs~ More realistic than a food chain Shows interconnected feeding relationships in an ecosystem Be able to construct a food web with up to 10 appropriate organisms

Some good links on BIOMES and Ecology in general http://www.thewildclassroom.com/biomes/biomes/grasslands.html http://www.thewildclassroom.com/home/nav/podastingscience.html http://mbgnet.mobot.org/sets/

Global climate Seasons • Precipitation & Winds

Biosphere~the sum of all the planet’s ecosystems Biome~ areas of predominant flora and fauna Abiotic factors Temperature Water Sunlight Wind Rocks & Soil Periodic disturbances

Terrestrial biomes Tropical forests~ equator; most complex; constant temperature and rainfall; canopy Savanna~ tropical grassland with scattered trees; occasional fire and drought; large herbivores Desert~ sparse rainfall (<30cm/yr) Chaparral~ spiny evergreens at midlatitudes along coasts Temperate grassland~ all grasses; seasonal drought, occasional fires; large mammals Temperate deciduous forest~ midlatitude regions; broad-leaf deciduous trees Coniferous forest/ taiga~ cone-bearing trees Tundra~ permafrost; very little precipitation

Lake stratification & turnover (SKIP) Thermal stratification~ vertical temperature layering Biannual mixing~ spring and summer Turnover~ changing water temperature profiles; brings oxygenated water from the surface to the bottom and nutrient rich water form the bottom to the surface

Marine biomes (SKIP) Intertidal zone~ area where land meets water Neritic zone~ shallow regions over continental shelves Oceanic zone~ very deep water past the continental shelves Pelagic zone~ open water of any depth Benthic zone~ seafloor bottom Abyssal zone~ benthic region in deep oceans

Aquatic biomes Vertical stratification: •photic zone~ photosynthetic light •aphotic zone~ little light •thermocline~ narrow stratum of rapid temperature change •benthic zone~ bottom substrate Benthos~ community of benthic organisms Detritus~ dead organic matter; food for benthic organisms

Freshwater biomes Littoral zone~ shallow, well-lit waters close to shore Limnetic zone~ well-lit, open water farther from shore Profundal zone~ deep, aphotic waters Lake classification: •oligotrophic~ deep, nutrient poor •eutrophic~ shallow, high nutrient content •mesotrophic~ moderate productivity Wetland~ area covered with water Estuary~ area where freshwater merges with ocean