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Transcript
ECOLOGICAL PRINCIPLES Concept 1 Ecology BIOSPHERE a thin blanket of life surrounding the earth which arises when atmosphere, land and sea meet – most fragile layer of the earth – 10 miles thick (5 miles up into atmosphere, 5 miles down into ocean) – ecosystems exist within the biosphere Arrangement of the Biosphere COMPONENTS OF A BIOME Biomes are large geographic areas defined by: -climate (temp, rainfall…) -soil type -type of plants ? (plants determine animals) Which division of the biosphere contains all other divisions? Question? From looking at the diagram, formulate your own definition of community! …hint…Think about what is included and what is not included Ten Major Biomes Biome Precipitation Temperature Soil Diversity Trees Grasses Tropical Rain Forest high hot poor high dense sparse Tropical Dry Forest mild rich moderate medium medium mild variable summer hot clay poor rich moderate moderate moderate sparse sparse absent dense sparse dense Temperate woodland summer low, summer hot and Shrubland winter moderate poor low medium medium variable Tropical Savanna variable Desert low Temperate Grassland moderate Temperate Forest moderate summer moderate, rich winter cold high dense sparse Northwestern Coniferous Forest Boreal Forest high rocky, acidic low dense sparse poor, acidic moderate dense sparse Tundra low summer mild, winter cold summer mild, winter cool summer mild, winter cold poor low absent medium moderate This is not in your notes because it would not copy well!!! Biome terms • Diversity-number of different kinds of living and non-living “things” • Temperate-distinct seasons • Tropical-consistently warm • Deciduous-plants shed leaves • Coniferous-leaves are year round Question? What is the biome description here at Central Dauphin? • ECOSYSTEM: a place where relationships between biotic and abiotic factors are affected by geology and climate – energy is processed through the biotic components – interrelationships create stability – populations are the basis of ecosystems • BIOTIC: living organisms (plants and animals) • ABIOTIC: non-living (water, minerals, soil…) • POPULATION: the number of organisms of the same species • SPECIES: organisms that can interbreed and produce fertile offspring ? Microclimates HABITATS • small subdivisions of an ecosystem where biotic components live and acquire the basic requirements of life • must include essential abiotic components • BASIC REQIREMENTS: food, shelter, water, space, air Habitat is the ADDRESS • varies in size • habitats overlap between different species • varieties of habitats increase diversity • BIODIVERSITY: number of different kinds of organisms within the ecosystem DIVERSITY = STABILITY • survival of the ecosystem is dependent on its diversity ? • the greater the diversity, the more likely an ecosystem could survive a cataclysmic event (like an extinction, volcano…) EDGES ARE VERY STABLE • the edge habitat (place where 2 habitats overlap) has the greatest diversity of plants and animals • edge is usually more stable than either of the 2 habitats it divides • edge shares species from both habitats as well as supporting edge only species This is not in your notes! This is not in your notes! Concept 2 Population Dynamics POPULATION DYNAMICS • Explains how wild populations control and maintain themselves • Based on the idea that resources are limited (CARRYING CAPACITY) • All species (plants and animals) must have the BASIC REQUIREMENTS OF LIFE – -FOOD, SHELTER, WATER, SPACE, AIR – AND OF COURSE THE RIGHT CLIMATE POPULATIONS • Members of the same species • Populations are limited in “range” by habitat, geology, climate and limiting factors within their habitat • Tends to be maintained within the carrying capacity and critical number LIMITING FACTORS • something that maintains population size within the habitats carrying capacity 1. 2. 3. 4. 5. 6. Food 7. Climate Competition 8. Disease Predation Geology/geography/topography Human influences Lack of any requirement of life Carrying Capacity • CARRYING CAPACITY: the number of organisms of a species that a habitat can support (provide basic requirements) Example: The pond can support 25 frogs. What may limit the number of frogs? Consequences • breaking the carrying capacity will cause collapse of the population • may lead to extinction • may reduce gene pool • may just reduce numbers long enough for the habitat to recover Can Carrying Capacity Change? • Yes • Increases with habitat improvement – Decrease in abusive population – Better weather promoting good food • Decreases with habitat destruction – Increase in populations above carrying capacity – Cataclysmic event (volcano) – Changes in climate (global warming?) Critical Number • The lowest number a species can drop to in an ecosystem and still recover – Set by nature to maintain genetic diversity – Prevents in-breeding and passing on “bad genes” Populations may stabilize • Stable populations will fluctuate between the carrying capacity and the critical number. • Most species with proper limiting factors will function along these lines • This is called DYNAMIC EQUILIBRIUM • These are called S-Curve populations Draw your own in your notes!!! S-curve Populations NUMBER Carrying Capacity Critical Number TIME causes of stabilization • • • • • • Emigration Immigration Death birth predator-prey disease These are limiting factors! J-curve Populations • Are not stable populations • Usually crash after they break carrying capacity • Due to lack of limiting factors or it has a special reproductive strategy – -many young with lack of parental care such as fish • May be an invasive species (gypsy moth) Draw your own in your notes!!! J-curve Populations NUMBER Carrying Capacity Recovery Critical Number TIME Extinction Species Interact with each other to maintain energy and population balances • Predator-Prey relationships Predators and Prey regulate each others populations ? • Competition -attempt to use the same limited resources -limits population size between competitors Categories of Competition • Interspecific: • Intraspecific: competition between 2 or more species for a single resource competition between members of the same species -usually for mates or nesting habitat or territory Interspecific competition shows competition can be Figure 4-5 Threehow Species of and(RESOURCE Their NichesPARTITIONING). avoided by sharingWarblers resources Section 4-2 This guarantees that all species survive and increase diversity Cape May Warbler Feeds at the tips of branches near the top of the tree Bay-Breasted Warbler Feeds in the middle part of the tree Spruce tree Go to Section: Yellow-Rumped Warbler Feeds in the lower part of the tree and at the bases of the middle branches • Parasitism -lives on or in a host species -often host specific -generally causes harm or death of host in extreme situations • Mutualism -both organisms will benefit from the arrangement -symbiosis arises through coevolution • Commensalism – one member of the relationship benefits – one member of the relationship gains nothing, but is not harmed example: lichens growing on the tree benefit from the tree, but the tree is not harmed or helped by the lichen Concept 3 Flow of Energy FLOW OF ENERGY Energy is processed Feedback input energy ecosystem output energy -this allows the ecosystem to maintain an energy balance NICHE = JOB • the way an organism makes a living in their habitat • niche describes how the organism gets it energy – producer (autotrophs and herbivores) – consumer (carnivores, scavengers) – decomposers NICHE WHAT THEY EAT TYPES OF ORGANISMS Autotroph Sunshine—these organisms make their own food Plants (the green guys) Herbivore Plants Bunnies, deer, bees Carnivore other animals-general term Lions, anteaters, fox, bass Predator Hunts, kills, eats other animals Lions, anteaters, fox, bass Parasite Lives on or in living organisms, on their body materials Ticks, tapeworms, fleas Omnivore Both plants and animals Bears, people, skunks Scavenger Dead or dying animals Vultures, crows, crayfish Detritivore Dead plants and leaves Beetles, fungus Decomposer Small particles and dead portions of other organisms Bacteria, fungus THE SUN IS THE SOURCE OF ENERGY FOR ALL LIVING THINGS (almost) – photosynthesis in autotrophic organisms converts sunlight energy into carbohydrates (BIOMASS) – they use oxygen to accomplish this – organisms are called photosynthetic autotrophs (plants and algae) • BIOMASS: the total weight of living matter in an ecosystem • It accumulates in the food chain as processed energy • Energy can be “lost” ? exception to the rule • CHEMOSYNTHESIS – organisms make carbohydrates out of carbon dioxide, water and inorganic compounds (like sulfur and nitrates) – organisms are called chemosynthetic autotrophs (deep ocean bacteria) Chemosynthetic organisms Deep Ocean Ecosystems FOOD CHAINS • a series of organisms which pass energy from one feeding level to the next • This process coverts one form of biomass to another • these levels are called TROPHIC LEVELS TROPHIC LEVELS • Primary Producer • Primary Consumer • Secondary Consumer • After secondary you can call them “higher consumers” by referring to their trophic level (3rd consumer, 4th consumer…..) Food Chains • always contain: sun, primary producer, decomposer – primary producer are autotrophs • the arrow points in the direction the energy is being transferred to • always flows in one direction • reads as “is eaten by” examples sun carrot rabbit sun acorns squirrel sun grass deer energy bacteria hawk bear human bacteria bacteria Primary consumer Primary producer Decomposer some general rules • Large carnivores do not eat large carnivores • herbivores do not eat carnivores • organisms within an ecosystem may compete for food sources • interacting food chains are called FOOD WEBS ? WHATS MISSING? ? ENERGY PYRAMID or PYRAMID OF BIOMASS Energy lost 10% to next level 90% used/lost at each level -biomass decreases at each step in a food chain -energy is lost at each step: bones not used, fur, energy expended in eating and metabolism, feces…. • larger organisms require more energy so there will be fewer at the upper levels • the shorter the food chain, the more organisms you can feed at the upper levels 1 human 300 trout 90, 000 frogs 27, 000,000 grasshoppers 1000 tons of grass 900 human 27, 000,000 grasshoppers 1000 tons of grass ? ? IV. MATERIALS CYCLE • MATERIALS CYCLE IN ECOSYSTEMS – water cycle – carbon cycle – nitrogen cycle All elements will cycle because the earth will run out of material if it does not! WATER CYCLE Water Goes Up Evaporation- heat causes the conversion of liquid water into gaseous water (water vapor) Transpiration- the evaporation of water from the surfaces of leaves -water is produced during photosynthesis Water changes form Condensation- due to cooling, gaseous water forms liquid water on the surface of a condensation nuclei Condensation nuclei- a small solid particle of matter in the atmosphere on which water will condense Water comes down Precipitation-the falling of a condensed form of water from the atmosphere -could be solid or liquid -occurs because the amount of water on the condensation nuclei becomes heavy and gravity causes the drop to fall 3 places water goes 1. Runs off into rivers, lakes, streams, wetlands 2. Percolates into the soil and is absorbed into plants 3. Percolates into the aquifer Percolate: to move into an area occupied by air and fill the molecular space The Aquifer •Aquifers are underground layers of porous rock or sand that allows the movement of water between layers of non-porous rock (sandstone, gravel, or fractured limestone or granite). • Water infiltrates into the soil through pores, cracks, and other spaces until it reaches the zone of saturation where all of the spaces are filled with water (rather than air). • The zone of saturation occurs because water infiltrating the soil reaches an impermeable layer of rocks which it can not penetrate any further into the earth • Water held in aquifers is know as GROUNDWATER • The top of the zone of saturation is known as the WATER TABLE. –. -The water table typically follows the form of the above ground topography. -The water table levels can change Drier =deeper wet areas =at or near surface • Two main forces drive the movement of groundwater – First water moves from higher elevations to lower elevation due to the effect of gravity – Second, water moves from areas of higher pressure to areas of lower pressure – Third, water moves at a rate and amount related to the size and amount of spaces in the rock layer Movement of ground water takes time—how much is variable, depending on the material it moves through and how deep you go. CARBON CYCLE Carbon Cycles through A. Food chains and Food Webs as biomass B. Decomposers release carbon as both a gas and an element C. Respiration of plants and animals Natural Sources of Carbon include: plants and animals, soil, fossil fuel deposits, atmosphere, humus….. -any form of biomass will be a place of carbon storage Man-made Sources of Carbon include: burning of fossil fuels and other organic materials Carbon Sinks Carbon Sink -long term storage of carbon 3 long term carbon sinks -deep ocean waters -deep ocean sediments -fossil fuel deposits Short term carbon sinks -plants and animals -atmosphere NITROGEN CYCLE Nitrogen cycles through A. Food chains and food webs B. Decomposition of biomass C. Water Natural Sources of nitrogen: biomass, decomposition, lightning, volcanoes Man-made Sources of nitrogen: fertilizers, industry, combustion of fossil fuels Nitrogen must be “fixed” Nitrogen is made in nature in an elemental form N2 -most living things can not use this form Nitrogen fixation -the process in which nitrogen fixing organisms convert N2 into useable forms -Nitrogen fixing Bacteria and Legumes are symbiotic organisms which fix N2 -fixed forms include Nitrates NO3-, Nitrites (NO2-) and Ammonia (NH4+) V. ECOSYSTEMS CHANGE • SUCCESSION CAUSES CHANGES IN ECOSYSTEMS – ecosystems are never static – ecosystems tend to move from less diverse to more diverse systems low species diversity high species diversity more energy available less energy available less biomass more biomass Primary Succession • occurs where no ecosystem has occurred before • uses pioneer species (lichens, moss) to form soils • begins on rock • often accompanies a cataclysmic event Pioneer Species • small plant organisms like lichens and mosses • their “roots” will gradually break off small chips of rocks • as they grow and die, the organic material mixes with the chips of rocks • soils begin to form (200 years = 1 inch of top soil) Secondary Succession • occurs in areas of disturbance of existing ecosystems • species who are opportunistic will begin process • opportunistic species are generally fast growing and have a high reproductive rate There are natural patterns of succession. -fields become forests -ponds become fields -forests will change types of vegetation until maturity Maturity • ecosystems will become more complex • complexity slows rates of change • the higher the maturity, the longer the ecosystem will stay in that state • in general--fields become shrub lands -- shrub lands become forests -- ponds will become grasslands • as the ecosystem changes, the species composition changes Fire Maintained Ecosystems • tends to halt/slow succession • maintains a particular successional state • some species require fire for reproduction • fire is used as a management tool to maintain ecosystems Climax Communities • all ecosystems tend to move toward an idealistic end state called a climax community • arguments occur about its existence • climax allows for very little change Concept 6 Invasive Keystone Native Invasive, Endangered, and Keystone Species • Invasive: a species that did not evolve in the habitat, it was released on purpose or by accident • Endangered: a species which are so close to the critical number that it may become extinct in the near future • Keystone: a species which is critical to the survival of an ecosystem-they are tied to many other species Invasive Species Gypsy Moths introduced into this country in 1869 have devastated much of the eastern oak forests. Non-native species do not have limiting factors to control their populations. This causes elimination of native species. Rabbits introduced into Australia have devastated the native grasslands and endangered kangaroos and other native wildlife. Endangered California Condor The largest bird of North America was brought to the brink of extinction due to: -over hunting -habitat destruction -egg collecting -DDT (pesticide) • In 1987, the last wild condors were removed and placed with the remaining population in captivitythere were 26 • A captive breeding program is in effect and as of 2012 there were 405 birds (226 in wild, rest in zoos) • Scientists question if they had reached the critical number as all 27 of the first breeding population had originated from 14 birds KEYSTONE SPECIESorganisms which are important in shaping the total ecology of an ecosystem Cray fish and Beaver are both keystone species in Pennsylvania. It is because they form habitats (like beaver) or are a major food source for many organisms. Either way they have major influence over their ecosystems. Loss of these species would result in ecosystem collapse. The Endangered Species Act • The law requires federal agencies, to ensure that actions they authorize, fund, or carry out are not likely to jeopardize the continued existence of any listed species or result in the destruction or adverse modification of designated critical habitat of such species. • The law also prohibits any action that causes a "taking" of any listed species of endangered fish or wildlife. Likewise, import, export, interstate, and foreign commerce of listed species are all generally prohibited. Trophic Cascade https://connect.usu.edu/p24408776/ • Occur when an organism has a key role in the balance of the ecosystem -removal causes changes throughout the entire ecosystem -can be top down or bottom up -often found after the removal of a top level predator • In Minnesota wolves suppress coyote populations, which in turn releases foxes from top-down control by coyote • The fox then control the intermediate prey species (bunnies and squirrels) • This allows the competition between the herbivores to produce dynamic equilibrium in populations of herbivores Remove the top predator • • • • Removal of Wolves releases the coyote Coyote control more fox Less fox, more bunnies and squirrels More bunnies and squirrels, greater competition between herbivores • Damage to autotrophic levels • Decline of herbivores and then their predators • Complete ecosystem collapse http://forestry.usu.edu/htm/video/conferences/rtw-2010/billripple/