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1. All organisms are made of cells Cells are the smallest unit of life 2. All organisms need energy Any living organism needs energy to live They take in and use energy. 3. All organisms respond to the environment What happens to an organism depends on the environment they are living in. 4. All organisms reproduce Living organisms can make more of themselves Two types: – asexual – sexual. 5. All organisms grow and develop Get bigger as they get older. 6. All organisms carry DNA Carry their own genetic code Traits are passed to offspring 7. Internal Balance (Homeostasis) Living things maintain stable internal conditions Examples – Temperature – Water Balance – Heart Beat Key Knowledge: 1. Matter Cycles, Energy Flows 2. Abiotic factors cause changes in Biotic factors in a ecosystem Abiotic: Non-living parts of the environment Soil Sunlight Climate Temperature Rainfall Nutrients Biotic: Living parts of the environment Plant Animals Decomposers (Bacteria and Fungus) General Organization Organism= any individual living thing Population= Individual organisms of a single species in one area. Community= more than one population living in the same area. Different species of fish Different species of corals (animals) Starfish (animal) Example of a Community Algae (microscopic plants) General Organization Ecosystem= All the populations and abiotic factors in an area. Habitat = the environment that a particular species prefers within an ecosystem Niche= the role that an organism fills “job” Biomes= Ecosystems with similar characteristics. Characteristics of a Biome No distinct boundaries Defined by types of plants Similar climate conditions, but may be located in a totally different part of the world ( Africa and Asia) –land biomes –water biomes (marine or freshwater) List the ecosystem structure from small to large.. Can make their own food through energy from the sun or inorganic substances AKA: Primary Producer Obtains energy by eating other organisms, AKA: Consumers Types of Consumers Primary consumers: eat producers (herbivores) Secondary consumers: eats both producers & consumers (omnivores) Tertiary consumers: top predator (carnivore) Trophic levels are a way of identifying what kinds of food an organism uses. 1st trophic level= primary producers 2nd trophic level= primary consumers 3rd trophic level= secondary consumers 4th trophic level= tertiary consumer Decomposers & Scavengers Decomposers feed on wastes & dead material from all trophic levels Ex: bacteria, fungi Scavengers are consumers that eat dead animals (like road kill) Ex: vulture Energy in an ecosystem is transferred (cycles) through the trophic levels of that ecosystem Biomass and Energy Transfer 1 hawk 10 snakes 100 mice feed 1000 plants feed ****Rule of 10**** Only 10% of the energy is transferred to the next organism Very few animals feed on only one food source, Food Webs are a more accurate picture of how animals feed. Biological Magnification The build-up of toxins in living organisms with movement up the trophic levels . Toxins collect in at the top of food web because top consumers eat so much. Examples: DDT: Dichloro Diphenyl Trichloroethane Developed during WWII as a pesticide Very high levels of DDT were found in top consumers. DDT is stored in fat. Organisms died or had reproductive problems Banned in US and Canada during the 70’s. Still found in almost all living things Developing countries are still use DDT Community Interactions In order to sustain an environment, organisms and abiotic factors interact EXAMPLES: –Symbiosis –Succession Forms of Species Interaction Symbiosis: relationships between two species (3 types) 1. Parasitism: one organism benefits at another’s expense ( Humans and tape worm) 2. Commensalism: one organism benefits while the other is unaffected (anemone and clown fish) 3. Mutualism: both organisms benefit from the interaction (rhino and bird) Forms of Species Interaction Continued Competition: two species are fighting for the same resources Predation: one species hunts the other Ecological succession: change in the types of species in a community observed over time Why does succession happen? Communities & environments change over time 1) Primary Succession When communities form in new areas – Ex: volcanoes, rocks, etc Steps of Primary Succession 1. Pioneer species appear lichens (grow on rock & turn it into soil) 2. 3. 4. 5. Pioneer Species: the first organisms occupy an area to Grass & small plants appear Weeds & shrubs Shallow trees (ex: pine trees) Climax community stable & final stage (ex: deciduous trees) Climax Community A community that has achieved stability and species diversity 2) Secondary Succession Occurs in areas that were cleared by disturbance (fire, etc) – faster than primary (soil already formed) Same as primary except pioneer species are grasses instead of lichens Succession leads to….. FACTORS THAT AFFECT POPULATION GROWTH 1.Birth Rate 2.Death Rate 3.Immigration (movement into an area) 4.Emigration (Movement, exiting an area) Exponential Growth J-shaped curve on a graph Population doubles every generation Humans are reproducing this way! Humans - Trouble ahead? Logistic Growth S–shaped curve on graph How real growth looks Populations grow fast early, then slow down, as we get closer to CARRYING CAPACITY Biomass and Energy Transfer at the lowest Trophic level determines the Carrying Capacity of the ecosystem. Carrying Capacity Maximum # of individuals a population can support – Populations will increase to Carrying Capacity, and they decrease again once they have reached it. Limits to Pop. Growth 1. Density-dependent limiting factors – Affect crowded populations – Disease – Competition (for shelter, food, water) – Predation (predator eats prey) How might the Bubonic Plague have been different if the Medieval populations didn’t live so close to each other? 2. Density-independent limiting factors – Affect all populations (crowded or not) – Weather – Natural Disasters (fire, etc) – Human activities New Orleans, LA Gulf Port , MS Would the physical effects of Hurricane Katrina be any different in a Town of 100, then in a town of 100,000? All matter essential for life moves in cycles between living things & the environment Examples of cycles: carbon cycle water cycle nitrogen cycle What is Carbon The basic building block of organic compounds essential for life. Why is carbon important to us? 1) Carbon is used to make hair, muscle, & skin 2) Carbon stores energy so living things can think, move, etc 3) Fossil fuels (gas, coal, oil) are made from carbon Where is carbon found in the environment? 1. 2. 3. atmospheric gas (CO2) rocks (limestone, diamonds) fossil fuels (oil, coal, etc.) How does carbon enter living things? 1) CO2 gas enters plants 2) Photosynthesis allows plants to change CO2 into a sugar 3) Animals then get carbon by eating the sugar found in plants How does carbon get back into the environment? 1. Plants & animals release CO2 during respiration 2. Burning of wood & fossil fuels 3. Using electricity, (most power plants use fossil fuels) 4. Cow farts (seriously) 5. Decomposition when bacteria and fungus break down tissue of dead things How are fossil fuels formed? 1. 2. When living things die & fall to the bottom of water, they are buried & compressed They eventually form coal, petroleum, or natural gas So what’s the cycle? the 2 main steps are photosynthesis & respiration! The Carbon Cycle The movement of carbon through the environment 2 major driving forces 1. Photosynthesis- plants and algae take up CO2 from the air or water to make sugar 2. Cellular Respiration- consumers use sugar for energy and release CO2 into the air or water Future Predictions Due to humans using more fossil fuels, more CO2 is released each year this may result in global warming since CO2 traps heat (remember the greenhouse effect) What is global warming? Facts about Nitrogen 78% of air is nitrogen gas (N2) Living things can’t use nitrogen when it’s a gas (N2) Why do living things need Nitrogen? To make amino acids & proteins To make DNA The Nitrogen Cycle Step #1 Nitrogen gas (N2) is found in the atmosphere Step #2 ”Nitrogen Fixation”: Bacteria living at the roots change the N2 gas into a usable form like ammonia or nitrates Lightning also “fixes” nitrogen Step #3 Plants then use the ammonia or nitrates in the soil Step #4 Animals get nitrogen from plants by eating them Step #5 When plants & animals die, the nitrogen in them is released back into the atmosphere as a gas (N2) This is done by denitrifying bacteria Step #6 Nitrogen gas is released back into the atmosphere What are the two process that are responsible; for cycling Carbon in the environment? What things add carbon? Which things take it away? Photosynthesis and Cellular Respiration Photosynthesis : take it away Cellular Respiration, Fossil Fuels and Decaying organisms add it. Breaking the Water Cycle The only way for water to get back to the atmosphere is through transpiration (plant sweating) When we cut down trees they no longer transpire So water does not get into the air to become rain The area becomes a desert in a very short time period – Really bad in rainforest regions, because the soil is so shallow HUMAN IMPACT A Sad True Story Invasive Species A species that is brought by HUMANS into a new environment and outcompetes the ones already there. Example: Africanized Honey Bees, which will take over the hive of the honey bees. An Ecological Mystery Long term study of sea otter population along the Alaskan and Aleutian Islands 1970: Sea Otters healthy and populations growing 1990: Sea Otter #’s declining – Maybe due to emigration, not deaths 1993: 800 km area in Aleutian Islands studied – Sea Otter #’s reduced by 50% Vanishing Sea Otters 1997: Study of area repeated Sea Otter pop. had declined by 90% – 1970: > 53,000 Otters in the study area – 1997: < 6000 Why? – Reproductive issues – Starvation, Pollution, Disease? Cause of the Decline 1991: one researcher observed an Orca whale eating a sea otter. Sea lions or seals are the normal prey of Orcas. Decline in usual prey led to feeding shift. Single Orca could consume 1,825 otters/year. Clam Lagoon (CONTROL GROUP), which was not accessible to Orcas, had no decline in otter population No Big Deal.. Right? Declines in ocean fish due to over fishing and climatic changes led to a reduction in food for sea lions & seals, so their #’s decreased This forced the orcas to enter into the coastal waters where they consumed sea otters. Sea otters normally feed on sea urchins. As sea otters decreased, the urchins numbers increased. Urchins eat kelp, and the large numbers of urchins damaged kelp forests. The decline in the kelp forests has had an impact on many others species because of the decrease of oxygen and an increase in carbon dioxide in the water. Other Species Affected Bald Eagle Mussel Sea Stars Seagulls