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OGT Cram Session 2 Structure of Ecosystems/Levels of Organization Organism – individual living (biotic) thing Population – group of organisms, all of one species, which live in the same place and the same time Community – all the populations of different species, same place, same time Ecosystem – Populations of plant and animals that interact with each other in a given area and with the abiotic parts (non-living) Biosphere – The portion of Earth that supports life Levels of Organization (cont.) I. Ecosystems Biomes A. Tundra This fact has been on 3 OGT Extremely cold climate (-34 degrees C to 12 tests! degrees C) Low biotic diversity Simple vegetation structure Limitation of drainage Short season of growth and reproduction B. Marine Cover ¾ the planet 1. Oceans 2. Coral Reefs Largest of all ecosystems Very diverse Coral is dominant organism Ex. Great Barrier Reef Estuaries Where freshwater rivers meet the ocean. Fertile soil produces diversity C. Freshwater Biomes 1. Ponds, Lakes, Streams D. Taiga Stretches across Canada, Northern Europe and Asia Soil is acidic and has few nutrients The abundance of evergreen trees provide shelter for many large animals Lynx, elk, caribou, wolves E. Desert Hot days Cold nights Little precipitation Low biodiversity F. Rainforest Hot temps High precipitation High diversity Contain species not yet discovered Being destroyed by deforestation Kills animals Reduces amount of oxygen G. Deciduous Forest/Temperate 70-150 cm of rainfall Deciduous trees Leaves turn color in fall Leaves fall off in winter Squirrels, mice, bears Biome Locations Succession Primary Succession When organisms colonize barren land (rock) Secondary Succession Areas that previously contain life Soil already exists Pioneer species – lichen break down rock Small ferns, fungi, and insects appear after lichen die Example: after a fire has burned a forest Climax Community Stable mature community Density-dependent factors Disease Competition Parasites Food availability Larger and closer a group is the greater the effect. 1. Density-independent factors Most are abiotic Temperature Disasters: floods, storms, drought, pollution Check this out…….(turn on volume) http://www.geowords.org/ensci/imagesbook/04_ 03_succession.swf Food Webs/Food Chains Food webs show what all organisms eat. a. Increase in the owl population A. The mouse population has increased Food Webs/Food Chains Food Chain is a straight line and only show 1 possible path of the food web Food Web/Chain Key Points If you get rid of an animal from the food web/food chain, the animal that eats the lost animal will decline in numbers. If you introduce an animal/organism to the food chain all animals who eat the new animal/organism will increase in numbers. If you introduce a species that eats the same organisms as another already in the food chain, then the animal already in the food chain will decline in numbers. (The visa versa is also true.) Animal Relationships Mutualism = Both animals benefit Commensalisms = One animal benefits, the other is not harmed. Parasitism = One animal benefits, the other is harmed! Carnivore = eats meat Herbivore = eats plants Omnivore = eats both Producers = make their own food (green) Consumer = eat producers Mutualism = both organisms benefit Yellow-billed oxpeckers feed on ectoparasites on the hide of a grazing bull hippopotamus. Parasitism A parasite feeds on a host. Usually the parasite does not kill the host (not immediately) Ex) tics (endoparasites-inside the host) Energy Pyramid Commensalism One-sided relationship. One species benefits with out harming the other species Competition When 2 or more species share similar characteristics and require the same resources they compete. Alien species- non-native species, reproduce out of control because they have no natural predators Carrying Capacity The population of a species that an area will generally support Usually there is equilibrium-a balance among species Autotrophs “Automatically” make their own food Producers Plants-that can make their own food by photosynthesis Heterotrophs Cannot make their own food. Animals must obtain food Herbivores-plants Carnivores-meat Omnivores-Both Environmental Problems Pollution-rise of industry has led to increased air and water pollution Ozone Layer Ozone absorbs the suns UV rays Without ozone, the UV rays would lead to genetic mutations in all living cells CFC’s break down the ozone layer Pesticides Poisonous chemicals to help control insects, but they become part of the water and soil harming other living things Acid Rain Pollutants in the atmosphere get washed out of the air when it rains These pollutants endanger the environment Here’s What they (OGT) has asked in the last 4 years……… Cell Theory 1. All organisms are composed of one or more cells 2. The cell is the basic unit of organization of organisms 3.All cells come from preexisting cells Prokaryote 1. Prokaryotes: No membrane bound organelles (especially nucleus) a. Bacteria (Kingdom Monera) b. DNA is just “floating” around along with ribosomes c. Mostly unicellular organisms Eukaryote 1. Eukaryotic: cells containing membrane-bound organelles a. mostly multicellular b. some unicellular (algae, yeast) C. have organelles: structures with special functions in the cell D. Nucleus: largest in animal cells Has Nucleus Ribosomes and DNA No Nuclear Membrane Cell Structure Cell Structures 1. Cell wall: rigid layer of nonliving material that surrounds the cells of plants Made of cellulose Protects and supports the cells 2. Cell membrane: Boundary that protects the cell from the environment & controls what comes in and out All cells have Like a screen door 3. Nucleus: control center for the cell 4. Ribosomes: grain like bodies on the ER & in the cytoplasm 5.Endoplasmic Reticulum: (called ER) carry proteins and materials within the cell 6. Golgi Body: receives and packages proteins from ER and distributes around cell and body (mailroom) 7. Cytoplasm: clear gelatinous fluid inside a cell 8. Vacuoles: storage area of the cell Plant has one large vacuole Stores food, waste, & enzymes 9. Mitochondria = powerhouse of the cell; where cell energy comes from. 10. Chloroplasts: ONLY IN PLANTS captures sunlight and produces food for the cell 11. Flagella = used for movement 12. Cilia = used for movement; tiny hair-like structures; found on cells that need to move mucus D. Absence of a nuclear membrane B. Viruses require a host cell to reproduce. C. flagellum B. flagella Questions they (OGT) has asked the last 4 years. D. Place the rabbit in a cage with a heated floor. B. D. Evolution Charles Darwin (1809-1882) 1. Natural Selection a. 2. 3. “Only the strongest survive” Darwin hypothesized that when animals had traits that helped them live, they would pass them on to their offspring. Animals who did not possess these traits died. Darwin’s Example 1. 2. Darwin noted the different beak structures of finches depended on the island they came from. Finches who lived on islands plentiful in nuts and berries had different beaks than finches who lived on islands plentiful in insects. Even though all these birds are finches they developed different beaks depending on the plentiful food source of specific islands. Examples of Natural Selection Galapagos Iguanas 1. a. b. c. d. e. Some iguanas have evolved to eat algae. Some iguanas have developed large claws to help them cling to rock. These iguanas evolved from other iguanas because they need those two traits to survive. The algae eating, long clawed iguanas passed these trait on to their young. Iguanas not having that trait. Everyday green iguana Galapagos marine iguana Other adaptations 1. Camaflouge a. Enables species to blend in with their surroundings. Can you find the snake’s head? 2. Mimicry – enables a species to look like other species What part of the plant is this? It’s not part of the plant at all, it’s an insect. Darwin Hypothetical 1. 2. 3. Let’s say there was a new “killer” virus that affected dogs. This flu bug only affected dogs with long hair. So, if a dog had long hair (more than ¾ inch long) it would get the virus and die. In 20 years, will all dogs have long or short hair? WHY? All dogs would have short hair because all the long hair dogs have died from the virus. There would only be short haired dogs mating with short hair dogs. You could say all dogs with short hair were “naturally selected” to live. The dog species has evolved from having both short and long hair to having only short hair. 1. Populations evolve not individuals. B. C. Had a higher survival rate than light moths in the same area One last thing the OGT might get you on…… Jean Baptiste Lamarck (1744-1821) Came before Darwin Had some of the same ideas as Darwin No one ever believed him. Died in obscurity and poverty. Genetics 1. The dominant trait will always be visible 2. Dominant-always masks the recessive; represented by uppercase letter (T, H, D, R) 3. Recessive-will be masked by dominant; represented by lowercase letter (t, h, d, r) -For a recessive trait to be visible, there must be two (tt, hh, dd, rr) DD dd Dd Punnet Squares Cross a homozygous dominant with a homozygous recessive. HH x hh h H H h h H H h h h H Hh Hh H Hh Hh OGT Tricks Sometimes they give you a recessive allele like c this: C c C is the same as a “c” A. O% D. 100% SEX alleles Males – XY Females – XX Recessive diseases Diseases that are recessive on the X chromosome INFO: Sex inherited diseases Females can not get diseases that appear on Y chromosome Males are more likely to get a recessive disease If the recessive allele appears on the X males get disease Females are less likely to get a recessive disease If recessive allele appears on one X chromosome the other X chromosome can cover it with a dominant allele How to Read Pedigrees Affected male Unaffected male Unaffected female Female carrier, She does not have Disease but can pass it on to her kids. Pedigrees = a chart that shows you the family history of passing traits