Unit 1 Review There will be multiple choice, fill in the blank, short answer and essay questions.

Hydrologic cycle Also called the water cycle Sunlight heats water causing evaporation Hot water molecules rise into the atmosphere As they cool they condense to form clouds When clouds become full the molecules fall as precipitation

Nitrogen cycle 78 % of earths atmosphere is nitrogen Nitrogen fixing bacteria convert nitrogen into ammonia and nitrates Plants absorb ammonia/nitrates through roots/ use to make amino acids/ proteins Animals eat plants for amino acids/ proteins Bacteria break down dead organisms and release the nitrogen back into atmosphere— denitrification Humans have added extra nitrogen thru artificial fertilizers

Oxygen cycle 21 % of atmosphere is oxygen Living organisms breathe in oxygen(O2) for cellular respiration After breaking down glucose, Carbon dioxide(CO2) and water are released Plants use the CO2 and H2O in photosynthesis to make glucose and O2 Air pollution traps O2 and forms ozone (O3)

Carbon Cycle CO2-carbon dioxide is in atmosphere Plants use CO2 in photosynthesis to make glucose Animals eat plants and break down the glucose with cellular respiration, releasing some CO2 back into air. The rest is used to make all parts of the body. When plants and animals die and are covered by layers of soil with pressure, they form fossil fuels which release CO2 when burned

Phosphorus cycle Limestone rock is weathered by rain and wind, releasing phosphorus into the soil and water Plants take phosphorus up through their roots Animals eat plants, drink water and get phosphorus Phosphorus is excreted in wastes of animals Humans add extra phosphorus with artificial fertilizers

All energy comes from the sun Food chain is 1 chain of organisms Food web is all the interconnected chains in an ecosystem Energy pyramid represents the different trophic levels and demonstrates how energy is lost as it moves up the levels

Food Chains

Food Web

Trophic Levels

Autotroph—makes own food-producer Heterotroph—eats something else-consumer –Herbivore—eats plants –Carnivore—eats other animals –Omnivore—eats both plants and animals –Detrivore—eats dead animals –Decomposer—breaks down organism to their basic nutrients

How can toxins move up a food chain? When toxins are taken up by plants, they may be small amounts As herbivores eat the plants the toxin levels increase slightly As carnivores eat the herbivores toxins become more intense As tertiary consumers eat carnivores, the toxins reach a deadly level and cause some type of harm--biomagnification

Human time line Hunter-gatherers: 10,000 ya; small nomadic tribes, ate berries, roots, small game, stalked large game; hunted many large mammals to extinction; burned prairies Agricultural Rev: 2000 ya to 1850s; farmers; grew crops; small towns; domesticated animals; large families; hand drawn plows and wagons; deforestation Industrial revolution: 1850’s to present; factories; large cities; mechanized equipment; steam engine; train; boat; car; smaller families; pollution

Developed vs Developing Developed countries have good health care, high incomes, high standard of living, slow or stable birth rates Developing countries have poor health conditions, low income, agricultural based economies, low standard of living, high birth rate, high death rate

Tragedy of the Commons When people have access to a “common” area, they abuse it They over fish, over hunt, pollute it, trash it, deplete the natural resources In order to have a public place, someone must create laws and police it. Set limits on things, fines for littering or polluting, etc. Sustainability is when everyone can have what they need to live comfortably and not deplete our natural resources

Decomposers Decomposers are necessary for all life to exist; They break down organic matter back to its original molecules so it can be recycled and used again

Laws Law of conservation of matter: matter can neither be created nor destroyed; it just changes form; chemical reactions—reactants equal products; matter is recycled through nutrient cycles. Law of conservation of energy: energy can neither be created nor destroyed; it just changes forms; radiant to chemical to mechanical, to physical; energy is not recycled but lost in the system as heat-- Entropy

Biotic vs Abiotic Biotic factors are any living or once living part of an ecosystem; plants animals, dead tree limbs, wood, leather, etc Abiotic factors include non living things such as air water, temperature, rocks, soil, nutrients, pH, etc

Good Luck