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Ecology
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Ecology Ecology is the study of ecosystems
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Ecology Ecologists have organized the living world into levels, for example: *organism *population *community *ecosystem
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An Organism An individual living thing that is 1. made of cells
2. uses energy 3. reproduces 4. responds to the environment 5. grows and develops
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A Population A population is a group of organisms, all of the same species, which interbreed and live in the same area at the same time.
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A Community A community is made up of interacting populations in a certain area at a certain time.
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An Ecosystem An Ecosystem is a population of microorganisms, plants and animals that interact with each other in a given area and with the abiotic components of that area.
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Abiotic and Biotic Factors
Abiotic Factors – Anything that is nonliving Ex. Water, soil, weather conditions, nutrients and temperature Biotic Factors – living organisms Ex. All bacteria, protists, fungi, plants and animals
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An oak tree ecosystem composed of various communities of organisms
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What is Climate? Weather is the day to day condition of Earth’s atmosphere at a particular time and place
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What is Climate? Climate is the interplay of many factors including latitude, the transport of heat by winds and ocean currents, and the amount of precipitation that results. The shape and elevation of landmasses also contribute to global climate patterns.
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The Greenhouse Effect Temperatures on Earth remain within a range suitable for life because the atmosphere stabilizes it Carbon dioxide, water vapor, and a few other atmospheric gases trap heat energy and maintain Earth’s Temperature Range
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The Greenhouse Effect These days we have more carbon dioxide from cars: more greenhouse gasses means more heat is trapped Just like a magnifying glass
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The Effect of Latitude Because earth is tilted on a 23.5 degree axis, it receives varying amounts of solar radiation. This can be demonstrated with a flashlight on a globe.
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Heat Transport in the Biosphere
Winds form because warm air tends to rise and cool air tends to sink A similar process happens with water
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Wind Patterns
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Ocean Currents
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Review So Far: What is the difference between weather and Climate?
What is the Greenhouse effect and why is it good? Name 3 Greenhouse gases
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Ecological Succession
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Succession Primary succession is the sequence of communities forming in an originally lifeless habitat Primary = first Succession = series, chain, progression
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Primary Succession Going from rock to forest
For example: a cooled lava field or bare rock newly exposed by a retreating glacier
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Formation of Soil The acidic secretions from lichen and weathering cause the break down of rock and the formation of soil
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Primary succession Once soil is formed, small plants and grasses begin to grow from seeds carried to the habitat by wind or animals
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Primary Succession The grasses become so dense that the lichens can not get light and they are replaced by additional grasses
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Primary Succession After many generations non-woody plants like shrubs, with deeper roots appear, increasing competition for sunlight. Keep going until we get to mature forests
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Some communities that continually suffer from disturbances may never develop into a climax community. Example: grassland; frequent fires disrupt succession.
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Secondary Succession Secondary Succession –occurs where a disturbance eliminates most organisms but does not destroy the soil. Examples: fire, storms, human activities
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Secondary succession Follows the same pattern as the later steps of primary succession
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The phases of succession
A pioneer community is the first to colonize a new area. Many times this is lichen, a mutualistic relationship of a fungus and algae.
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Weeds and grasses Shrubs Smaller trees Large trees Pioneer Community
Climax Community
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Climax Community – a community that does not undergo further succession
These communities are usually highly diverse and often survive severe disturbances….like forest fires
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Food Webs Food webs demonstrate the energy flow within an ecosystem.
The main source of energy for all of life is the sun.
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Trophic Levels Trophic levels are each step in energy/matter transfer.
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Niche a term describing the way of life of a species. Describes how an organism or population responds to the distribution of resources and how it in turn alters those same factors
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Niches
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Producers Includes your autotrophic plants
Use energy from the sun and make their own food. Get eaten by consumers
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Consumers All consumers are heterotrophic – they eat to live, and include: Herbivores – eat plant material; examples are grasshoppers, mice, rabbits.
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Consumers Carnivores – eat other animals, examples are foxes, frogs, snakes Omnivores – eat both plants and other animals, examples are bears, turtles, etc.
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Decomposers Decomposers - break down the complex organic compounds into simple nutrients. Take care of breaking down (cleaning) dead materials.
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The more connections and complications a web has, the more stable it is
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Relationships Predator and Prey – population sizes are closely linked
Increases in the prey population causes an increase in the predator population and vice versa
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Symbiosis – any relationship where two species live closely together, can be a harmful, beneficial or neutral relationship 1.commensalism – relationship that benefits one species and neither helps or harms the other. example: barnacles on a whale
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2. Mutualism – relationship where both species benefit
Examples: pollinators and flowers Ants on an acacia tree
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3. Parasitism – a harmful relationship, where one organism feeds on the body fluids or tissue of another Host = organism that the parasite feeds on The parasite is harmful to the host and can even be fatal
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Competition Competition occurs when organisms try for the same food or living space.
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Population Growth A species’ growth is limited by abiotic and biotic factors. Called LIMITING FACTORS examples: food, water, shelter, predation
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Population Growth Without these limiting factors, a population would overpopulate itself, thereby increasing competition for resources.
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Every population has the potential to increase exponentially.
Exponential Growth - Growth in which the rate of growth in each generation is a multiple of the previous generation
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Population Growth This type of growth occurs in every population until it reaches it’s carrying capacity.
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Carrying Capacity Carrying Capacity- the limiting number of organisms that a given ecosystem can support. As a population grows, competition for resources increases.
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Carrying capacity This competition causes a rise in the death rate and a drop in the birth rate The carrying capacity is met when the # of births = # of deaths.
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As a population approaches it’s carrying capacity growth slows
Growth STOPS when the carrying capacity is reached
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Age Structure Histograms
These show the population of a given area at each age level. This type of chart can be useful in planning ahead in making accommodations for an increase in elderly or child care.
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