Biology 20

1. Biology 20 Equilibrium in the Biosphere

2. Ecology • explain the one-way flow of energy through the biosphere and how stored biological energy in the biosphere is eventually “lost” as thermal energy • explain how biological energy in the biosphere can be perceived as a balance between both photosynthetic and chemosynthetic, and cellular respiratory activities

3. Ecology • Study of the interactions between organisms and their physical environment and with each other. • includes aspects of both the living (biotic) and non-living (abiotic) components of the physical environment.

4. Biosphere • Biosphere • the part of the earth that is inhabited by organisms. 3 parts: • Lithosphere • Land • Hydrosphere • water • Atmosphere • The gasses that surround the Earth.

5. Living vs. Non-living • There are two factors which make up the biosphere. • Biotic Factors • Living components of the biosphere • plants and animals… • Abiotic Factors • Non-living components of the biosphere • minerals, water, weather...

6. Interactions Within the Biosphere • Abiotic vs Biotic • When a non-living factor affects a living factor. • i.e. The weather affecting a living organism • Biotic vs. Biotic • When a living factor affects another living factor. • i.e. Two organisms fighting for the same food. • Biotic vs. Abiotic • Abiotic vs. Abiotic

7. Levels of Organization

8. Levels of organization Cell Tissue Organ System Organism Population Community Ecosystem Biome Biosphere

9. Levels of Organization

10. Hierarchical Levels within the Biosphere Biosphere Ecosystem Community Population Organism World Lake or River Lots of different species of organisms Lots of same species of fish Fish

11. Important Definitions • Population: group of individuals of the same: species,place & time • Community:populations of all species in an area • Ecosystem: community and its biotic and abiotic factors • interactions • Biome: large scale ecosystems • Can be found around the world  tundra, grassland

13. Food Chain • a linear illustration that represents the step sequence of who eats whom in the biosphere. • used to show: • energy transfers • cycling of matter through the biosphere • Two types: • Grazer: plant, herbivore, carnivore • Detritus: organic waste • Waste – scavengers – decomposers

14. Assignment 1.1 • Use your text book and define the following Terms • Biodiversity • Producer • Consumer Read pages 8-10 (new text only) Do Questions 1-7 section 1.1 page 10

15. Equilibrium Unbalanced

16. Autotrophs • “self feeders” • Require energy from sun – photosynthesis • Convert energy from sun into a form of energy that other living things can use • Provides O2 – required by all living things • Provide basic molecules for life • Carbohydrates, proteins, fats, and nucleic acids • PRODUCERS!

17. Heterotrophs • Require a source of chemical energy and basic organic molecules • NO photosynthesis • Feed on plants OR other heterotrophs • CONSUMERS! • A primary consumer eats a producer • A secondary consumer eats a primary consumer • A tertiary consumer eats a secondary consumer…

19. General Terms • Herbivore • An organism that only eats plants. • Rabbit, squirrel • Carnivore • An organism that only eats animals. • Wolf, Lion, Tyrannosaurus Rex • Omnivore • An organism that eats both plants and animals. • Bear, Human

20. More General Terms • Scavenger • An organism that feeds on dead organisms or the wastes of organisms. • Vulture, Seagull, • Decomposer • An organism that breaks down organic wastes and the remains of dead organisms into simpler compounds such as: • carbon dioxide • ammonia • Water

21. Species At-Risk Species At-Risk

22. Species At-Risk • Indicator Species – A species sensitive to small changes in environmental conditions

23. Describe why frogs and other amphibians are important indicator species: • Frogs live in two different ecosystems • Water as a tadpole • In forest and grassland as adults Any hazards in either ecosystem will have an effect on the frogs. • Also frogs occupy two different food chains.

24. Why Are Frogs Disappearing? • The worldwide disappearance of frogs is puzzling scientists around the globe. - Loss of Habitat • Frogs need wetlands, ponds, or lakes with clean water to breed and lay their eggs. • They need a place where they can catch insects such as forest and fields.

25. - Air and Water Quality • Frogs can breath through their skin, pollutants can also pass through their skin. • Acid of water also has an ability to reproduce. - Climate Change • Climate change can cause important changes in local ecosystems. • If the climate becomes drier frogs populations will decline.

26. 4. Ultraviolet Radiation • The thin skin of the frog is susceptible to ultraviolet radiation. • The amount to UV radiation reaching Earth's surface is increasing because of damage to the protective ozone layer surrounding Earth.

27. Biology 20 Ecology Energy and Matter Exchange

28. General Terms • Ecosystem • A community of organisms interacting with each other and with their nonliving surroundings. • Autotrophs –Producers • Heterotrophs - Consumers

30. Biogeochemical Cycles Input energy Ecosystems are OPEN SYSTEMS. Energy and matter can flow in and out of system Energy Lost

31. Ecosystem Models Explain the structure of ecosystem trophic levels, using models such as food chains and food webs

32. Food chains • Food Chain • step sequence of who eats whom in the biosphere. • used to show: • energy transfers • Characteristics: • Energy is transferred from organism to organism • Each time energy is transferred about 90% is lost as heat or used for life processes

33. Food Chain • Note that: • the arrow points at the eater • the arrows separate trophic (eating) levels

34. Trophic Levels • Trophic level: how far an organism is from the original energy source • Plants – first trophic level • Original energy is from the sun • When an organism is ingested by another, energy is transferred • Plant – mouse – owl • Producer – primary consumer – secondary consumer (top carnivore) • T1 – T2 – T3

36. Food Webs • What would happen if we relied on deer for our food? • In reality, a consumer relies on more than one food source • If one source is scarce, consumer can eat more of something else • Food web: • a series of interlocking food chains • more accurately represents energy pathways • who eats whom… really

37. Food Web • ABCD represent different trophic levels. • Level D represents the decomposers

41. Laws of Thermodynamics • Biosphere requires a constant flow of energy • Energy flows one way through the biosphere following basic scientific principles called the laws of thermodynamics

42. Laws of Thermodynamics First Law Energy can be changed in form, but not created or destroyed. (Law of conservation of energy) Energy input = Energy Output

43. Second Law Any energy change results in loss of energy as heat Energy input  desired energy + waste energy

44. Energy Flow • About 10% of the energy is transferred from one trophic level to the next.

45. During any change, some of the energy is lost as waste energy or heat. • Applied to an ecosystem, as energy flows through the community there is energy loss at each trophic level. • Much of this loss is in the form of heat which is lost when food molecules are broken down in the cells. • There would be less energy loss in the community if only herbivores fed on the producers

47. Energy Flow in the Ecosystem explain quantitatively, energy exchange in ecosystems, using models such as pyramids of energy , biomass, and numbers explain the interrelationship of energy, matter and ecosystem productivity (biomass production)

48. Ecological Pyramids • Ecological pyramids illustrate the energy loss through the trophic levels • Solar radiation transformed in plants • Plants create chemical energy • Plant eaten by consumer • Energy lost at each transformation • Higher trophic level = less energy available • Number of trophic levels limited b/c of loss of energy

49. Ecological Pyramids • In ecological pyramids, • Base -the producer populations • Next Level - the primary consumers • Higher levels and above -the secondary, tertiary etc.