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Ecology Biology I The Hierarchy of Life • • • • • • • • • • • • • • Atoms Molecules Macromolecules (proteins, lipids, carbs, nucleic acids) Organelles Population: a group of same species all living together and Cells interacting (ex. A population of Tissues deer) Organs Community: all of the different Organ systems living things in the same area that interact (plants, deer, foxes, Organisms racoons, etc.) Populations Ecosystem: all of the living and Communities non-living things in an area Ecosystems Biome – like ecosystems found Biomes throughout the world (desert, bioshere forest, grasslands, etc.) Abiotic vs. Biotic Factors • Abiotic – non-living things • Biotic – living things Ecosystem Ecology • The study of the flow of matter and energy through ecosystems – Food Webs – Energy Pyramid – Carbon, Nitrogen, & Water Cycles Food Webs Food Webs – show the flow of Energy • All energy enters the food web by the producers (photosynthesis) • Energy Flows through the food web and is not recycled • Matter is recycled by the decomposers • Trophic Levels – feeding levels Food Webs Continued • Producers - synthesize organic molecules from inorganic molecules and the sun’s energy (produce about 170 billion tons or organic material/year) • Consumers – never more than 3-5 trophic levels since the producers can only support so many consumers – Primary Consumers – eat producers – Secondary Consumers – eat the primary consumers – Tertiary Consumers – eat secondary consumers • Decomposers – break dead things back down to inorganic materials Food Webs Continued • Autotrophs – make own food (producers) • Heterotrophs – must eat to get food (consumers and decomposers) • Herbivore – plant eater • Carnivore – only eat animals • Omnivore – eat either plants or animals Energy Pyramid • Maximum of 3-5 trophic levels • 5-20% of energy is transferred to the next trophic level – lose 80-90% of energy in the transfer to the next level • Why is Energy lost before getting to the next level? – – – – – Lost in CR (energy is used) Energy is lost as heat Energy is used to eat and get food Lost in feces Some of the molecules cannot be broken down and used for energy (cellulose, bone, etc.) Energy Pyramids Cycles Matter is recycled inorganic→organic→inorganic Cycles between: • Soil – abiotic reservoir for elements • Air – abiotic reservior for elements • Rocks – unusable abiotic reservoir, can be used after erosion • Living Organisms – reservoir for organic matter Water Cycle Water Cycle • Precipitation going into the soil of bodies of water is how water enters the food web • It leaves the living things by transpiration and cellular respiration and evaporation from the bodies of water to go back into the air Carbon Cycle Carbon Cycle • Carbon enters the food web from the air thru photosynthesis • Passed thru food web by eating • Returned to the air by cellular respiration, decomposition, and combustion Nitrogen Cycle Nitrogen Cycle • Nitrogen makes up most of the air but it is unusable since it is N2 and almost no living things have enzymes that can break that bond • Special Nitrogen fixing bacteria can turn N2 in the air into useable nitrogen that can be sucked up by plants and used to convert sugars to aa and nucleotides • Decomposition of dead things and feces and urine also puts nitrogen into the soil • Nitrogen enters the air by denitrifying bacteria Nitrogen Cycle Human Impact on Cycle • Acid rain is carried by the wind • Moving nutrients or removing them all together • Fertilizer can cause eutrophication of lakes (too much nutrients lead to too many photosynthetic organisms – clog lake) • Introduce toxins into the enviroment (biomagnification) • Ozone depletion • Urbanization • Introduction of exotic species • Genetically engineering plants to resist herbicide and weeds, fish engineered to resist cold temps. Community Ecology • The study of interactions and relationships among the organisms in an ecosystem (why are certain species found together, how do they adapt to one another?) Community Ecology Relationships 1. Symbiosis – close relationships where the organisms are interdependent – Mutualism – good for both (pollination, E-Coli in intestine, nitrogen fixing bacteria and plants, etc.) – Commensalism – good for one, doesn’t help or hurt the other (barnacles on whales) – Parasitism – good for one, hurts the other • Endo – tapeworms • Ecto – ticks, leeches Mutualism Commensalism Parasitism Relationships Continued 2.Predator/Prey – causes both behavioral and evolutionary adaptations Prey • Behavioral Adaptations – learn to hide, warn each other • Evolutionary Adaptations – make prey better at avoiding being found, captured, or consumed – selected for over many generations! – – – – – Warning colors Mimicry Camoflage Defensive postures speed Predator/Prey Relationships Continued Predator • Evolutionary Adaptations – makes the predator better at finding, capturing, and eating prey – – – – – – Teeth Camoflage Speed Heated pits Lateral lines Spider webs Population Cycles Amt. of prey controls amount of predator and vice versa •as rabbits go up – lag and then predators increase because get more to eat more energy to reproduce •too many predators – eat too much prey – predators start to die off because not enough food •Less predators, more prey survives - #’s increase etc. etc. 3. Plant/Herbivore Interactions – Relationships Continued • Evolutionary – plants develop defenses – – – – – Prickles Thorns Tough leaves Stick hairs Toxic chemicals (nicotine, strychnine, etc.) Co-Evolution – plant better defends, herbivore overcomes defense, plant develops new defense, etc. etc. 4. Competition – Still Relationships • Several species competing for homes, food • Usually this is not really a relationship because it causes behavioral and evolutionary adaptations that eliminate the competition • Behavior Adaptation – niche switching – animals change niches (roles) so no longer competing – ex. Birds competing for homes in a tree – some live high in the tree, other species lives lower • Evolutionary Adaptations (slow gradual change over time to organisms best suited – competition dies off) – Ex. Plants that release toxins in soil that kill surrounding plants like mesquite in the desert – Ex. Characteristics that allow them to get food better – finches beak – Killer bee queen killing other queens at birth so there will only be killer bees. Succession • Succession – a slow gradual change in a community over time – not evolutionary adaptations to environment – due to the # and type of organisms that live in an area based on things moving in and others dying out • When some plants move in they make it more hospitable to other plants enabling them to move in and they choke off the plants that were originally there Succession Continued • Primary Succession – on land that previously contained no life – ex. New islands, rock, area of a retreating glacier • Secondary Succession – replacement of species after a major disruption (fire, flood, volcano, tsunami, over grazing • In both the land is colonized by species which are gradually replaced Succession Continued 1. Pioneer Plants (weeds, herbs, tiny shrubs, moss, lichens Good at colonizing – small, fast growing, fast reproducing, good seed dispersal 2. Grasses – trap soil and moisture making it better for trees to grow 3. Trees – usually more competitive and will eventually take over – shade out smaller plants Climax Community – stable community – succession has stopped – no more species can fit Succession – gradual change in species over time due to new things moving in Population Ecology • The study of what affects the numbers and make-up of organisms in a population • Factors that affect population growth – Competition within species for same resources – more organisms, decrease in food and survival – Predation (more deaths as population increases) – Build up of toxins – Stress (high density induces stress and makes hormonal changes to animals, reproduce less and die quicker – Climate – Natural Disasters – Disease Population Ecology Continued • Population cycles – populations vary with regularity caused by: – Stress due to overcrowding – population gets too big and then declines – Inability to find food, homes, shelter, etc. when population gets large – Build up of toxins in a large population – Build up of prey, followed by a build up of predators which eat more prey making them decrease, which causes death of predators since they don’t have enough food Organismal Biology • Study of how organisms are adapted to their environment • Abiotic Factors determine what things can live in an area • Types of Adaptations: – Behavioral (animals only) – migration, hiding under a rock, burrowing into the ground – Physiological (reversible) – takes minutes to weeks – ex. Ability to constrict blood vessels to respond to the cold, making more RBC’s when go to high elevations that are lower in oxygen Organismal Ecology Continued • Morphological Adaptations – change form or anatomy (grow fur, change coat color, change leaf shape) • Evolutionary Adaptations – cactus having spiny leaves and super thick cuticles Biomes – areas with similar environments and also similar living things • Aquatic – oceans, freshwater, wetlands, estuaries • Terrestrial – tropical rainforest, temperate rain forest, deciduous forest, coniferous forest (taiga), temperate grassland, tropical grasslands (Savanna), chaparral, tundra, desert