Ch. 4

1. Ecosystems and Energy Ch. 4

2. Levels of biological organization

3. “eco-” = house The study of the interactions among organisms and between organisms and their abiotic environment Abiotic factors: sunlight, wind, living space, precipitation, temperature, soil, wind Studies levels of biology above the individual Ecology

4. Populations: groups of species (members breed naturally to produce fertile offspring) Communities: all the populations in an area Ecosystem: the community including the abiotic factors.

5. Biosphere – layer of earth containing all living things. A study would include the air, water, land and organisms. • Atmosphere: gaseous layer surrounding Earth • Hydrosphere: Earth’s water– frozen and liquid • Lithosphere: soil and rock of Earth’s crust

6. Energy • Essential for life • The capacity/ability to do work • Units: Joules (J) – units of work - or calories (cal) – units of heat energy • Forms: chemical, radiant/solar, heat, mechanical, nuclear, and electrical • Can be stored – potential energy – or as moving energy – kinetic energy.

7. A plant that a meadow vole (rodent) eats contains chemical potential energy and is converted to kinetic energy and heat as the vole moves. Biological example

8. thermodynamics • Study of energy and its transformations • Closed system – an object being studied that exchanges energy, but not matter with its surrounding. • Open system – an object studied that can exchange energy/matter with its surroundings.

9. Energy cannot be created or destroyed. It can transform from one form to another. • Ex: absorb energy from the sun or give off energy to surroundings. It changes, but wasn’t created or destroyed. • All living things need energy and can’t create it. They must get it from their environment. Plants get solar energy and convert to chemical energy in the bonds of sugar. Animals get energy (chemical) from eating plants/animals and convert energy to mechanical energy for movement. First law of thermodynamics

10. When energy transforms, some usable energy degrades into heat, a less-usable form of energy. • Usable energy for biological work decreases through an ecosystem. • Entropy: a measure of disorganized, less-usable energy. • If all energy were heat, life would cease to exist. • Entropy increases through an ecosystem. Second law of thermodynamics

11. Energy conversion is never 100% efficient, some energy is always “lost” as heat. And automobile is about 25% efficient converting chemical energy of gas to mechanical energy Cellular metabolism is about 50% efficient. Efficiency of energy conversion

12. Producers are essential for getting energy into organisms  photosynthesis and chemosynthesis (from hydrogen sulfide – H2S @ hydrothermal vents) • Biological process by which energy from the sun (radiant energy) is transformed into chemical energy of sugar molecules 6 CO2 + 12 H2O + radiant energy  • Energy captured by plants via photosynthesis is transferred to the organisms that eat the plants Photosynthesis C6H12O6 + 6 H2O + 6 O2

13. The process where the chemical energy captured in photosynthesis is released within cells of plants and animals • This energy is then used for biological work • Creating new cells, reproduction, movement, etc. Cellular Respiration C6H12O6 + 6O2 + 6 H2O  6 CO2 + 12 H2O + energy

15. Producers/autotrophs: land – mainly plants; water – algae, phytoplankton • Consumers/heterotrophs: primary, secondary, tertiary and herbivores, carnivores, omnivores, detritus feeders/detrivores • Decomposers/saprotrophs– microbial, return inorganic molecules (carbon dioxide, salts) to environment Producers, consumers, decomposers

16. One way; once energy has been used biologically, it becomes unusable Follows food chain Trophic levels Food webs – realistic model Energy Flow through an Ecosystem 10 % rule!!!

17. Food web

18. NOTE: ARROW DIRECTION, LOCATION OF PRODUCERS

19. Pictures to represent available energy Ecological pyramids

20. Pyramid of numbers • # of organisms with appropriate area according to size. • Inverted pyramids do exist: decomposers, parasites

21. Pyramid of biomass • Biomass= measure of total amount of living material

22. Pyramid of energy • Units typically kilocalories per square meter per year • Less energy available at each successive trophic level. • 10% rule

23. Gross primary productivity (GPP): • Total amount of energy captured during photosynthesis (for a given time period) • Net primary productivity (NPP): • The amount of energy left after cellular respiration in the plant; plant growth per unit area per unit time) • NPP = GPP – plant respiration • NPP is the energy available to consumers primary productivity

24. CHECK FOR UNDERSTANDING • If a forest nets 1500 g/m2/yr and uses 1000 g/m2/yr. How much energy does that forest capture annually? • 4 – I feel extremely confident about any calculations regarding primary productivity • 3 – I feel confident about primary productivity calculations • 2 – With a bit more help I could do these calculations • 1 – I really don’t get this

25. What abiotic factors effect productivity? Know the most/least productive environments and why they are/are not productive.