ecology, ecosystems, and population dynamics. ecology: the study of the interactions between living...
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Ecology, Ecosystems, and Population Dynamics
ECOLOGY: the study of the interactions between living things and their environments
Ecological Hierarchy
Population• A group of individuals that interbreed and
therefore share the same gene pool• A population can evolve as the individuals’
offspring undergo changes in phenotype and genotype
Community • A group of populations that live in a particular
environment that interact with one another in many different ways
Niche• The way an organism lives in its environment,
including its nesting behavior, what type of food it eats, and where it hunts
• Competition between populations in similar niches drives evolution
Community Roles• Producers: have all of the raw
building blocks to make their own food; convert light energy to chemical energy via photosynthesis
• Consumers: forced to find their energy sources in the outside world; digest the carbs of their prey to make organic substances
• Decomposers: break down organic matter into simple products; fungi and bacteria serve as the “garbage collectors” of the environment
• Ecosystem: Self contained region that include both living and nonliving factors; there is an exchange of materials between the components of an ecosystem
• Carbon Cycle: the way carbon is recycled through an ecosystem
Biomes• Massive areas that are classified on the basis
of their climates and plant life; usually arranged along particular latitudes
Types of Biomes
Tundra• Northernmost regions• Grasses/wildflowers; few trees• Contains permafrost• Arctic foxes, snowy owls, reindeer
Types of Biomes
Taiga• Northern forests• Wind blown conifers, stunted in growth with
spikes• Very cold long winters• Caribou, wolves, moose, bears, rabbits, and
lynx
Types of Biomes
Temperate Deciduous Forrest• Northeast and Mideast US, Western Europe• Deciduous trees that drop their leaves in
winter• Moderate precipitation, warm summers, cold
winters• Deer, wolves, bears, small mammals, birds
Types of Biomes
Grasslands• Midwest. US, Eurasia, Africa, South Africa• Grasses• Hot summers, cold winters; unpredictable rain• Prairie dogs, bison, ferrets, grouse, lizards
Types of Biomes
Deserts• Western US• Sparse, includes cacti, drought-resistant plants• Arid, low rainfall, extreme diurnal
temperature shifts• Owls, kangaroos, snakes
Types of Biomes
Tropical Rainforests• South America• High biomass, diverse plant life• High rain and temperatures, impoverished soil• Snakes, monkeys, birds, leopards, insects
Biosphere
• The entire part of the earth where living things exist, including soil, water, light and air
• Relatively small in comparison to overall mass of earth
Food Chain• Tertiary consumer- eat everything• Secondary consumer: feed on primary consumers and producers• Primary consumers: feed directly on producers• Producers (Autotrophs): produce all available food; possess the
highest biomass (total weight of all the organisms in an area) and the greatest numbers
• Decomposers are not considered part of food chain; can decompose ANY organism
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The 10% Rule• Only about ten percent of the energy is transferred
from one level to the next, with other 90 percent being used for respiration, digestion
• In an ecosystem, tertiary= least energy, producers = most energy
Ecological Pyramid: Represents the energy flow, biomass, and numbers of members within an ecosystem; higher up pyramid = less biomass and energy
Symbiotic Relationships
Mutualism: both organisms benefit
Commensalism: one organism lives off another with no harm to the host
Parasitism: the organism actually harms its host
Population Ecology: the study of how populations change, looking at size, density, distribution patterns, and age structure
Survivorship Curves
• Graphs showing number of individuals living to different ages, indicating probability of an individual living to an age
• R= (births – deaths)/ N, where R is the reproductive rate, N is population size
Life History StrategiesR-selected organisms: live in unstable
environments and multiply before competitors arrive to produce a lot of offspring; e.g. dandelions and mice
K-selection: stable environments; produce only a few offspring; equipped to deal with competition;
e.g. redwood trees and human beings
Exponential growth
Ideal, unrestricted growth because of unlimited resources
Logistic growth
In actuality, at some point the population size becomes restricted by limited resources
Carrying Capacity
The maximum population size that a particular environment can sustain
Li
miting
Factors:
a factor that control’s
a
populati
on
growth
• Density Independent: affects the population regardless of density of population; e.g. severe storms, extreme climates
• Density Dependent: depends on population density; e.g. resource competition/depletion and predation
Limiting Factors
ECOLOGICAL SUCCCESSION: The predictable procession of plant communities over a relatively short period of time
Primary Succession: the process of ecological succession where no organisms
previously existed
Sere: entire sequence of different plant communities
Pioneers: make the area more habitable, setting the stage for other organisms
Climax community: the final community
Secondary Succession: when a new community develops where another community has been destroyed or disrupted (e.g. after a fire)
HUMAN IMPACT ON ENVIRONMENT
Greenhouse Effect: increases atmospheric competition of carbon dioxide through burning of fossil fuels and forests; causes warming of earth
Acid Rain: burning of fossil fuels produces sulfur dioxide and nitrogen dioxide, which react with water in clouds to produce rain that lowers pH of aquatic ecosystems and soil
Desertification: when land is overgrazed by animals
HUMAN IMPACT ON ENVIRONMENT
Deforestation: clearing of forests causes erosion, floods, weather pattern changes
Pollution: as toxins move up tropic levels, they become more concentrated by biomagnification
Reduction in biodiversity: different habitats are destroyed, causing plants and animals to become extinct; ecosystem becomes more vulnerable to changes and threats
HUMAN IMPACT ON ENVIRONMENT
• http://www.tutorvista.com/content/biology/biology-iv/organisms-environment/organism-and-environment.php
• http://eo.ucar.edu/kids/green/cycles6.htm• http://vcebiology.edublogs.org/category/population/• http://en.wikipedia.org/wiki/File:Survivorship_Curves.jpg• http://worldslife-nisha.blogspot.com/2011_06_01_archive.html• http://www.greenbusgroup.com/human-ecology.html• http://ocw.tufts.edu/Course/21• http://laurenyoung3b.edublogs.org/2012/04/27/levels-of-organization-in-an-environment/• http://fitz6.wordpress.com/2012/01/09/producers-and-consumers/• http://cikgurozaini.blogspot.com/2011/09/ecosystem.html• http://www.marietta.edu/~biol/biomes/biome_main.htm• http://www.blueplanetbiomes.org/tundra.htm• http://www.plantsystematics.org/reveal/pbio/biome/lec35a.html• http://www.marietta.edu/~biol/biomes/tempded.htm• http://www.blueplanetbiomes.org/grasslands.htm• http://www.proprofs.com/quiz-school/story.php?title=identifying-biomes• http://solarsystem.nasa.gov/multimedia/display.cfm?Category=Planets&IM_ID=9683• http://www.kidsgeo.com/geography-for-kids/0162-food-chains.php• http://www.transtutors.com/homework-help/biology/living-organism-and-environment/
commensalism.aspx• http://www.cbu.edu/~seisen/ExamplesOfParasitism.htm• http://math.tutorvista.com/algebra/exponential-growth.html• hann1900.tripod.com• http://www.globalchange.umich.edu/globalchange1/current/lectures/competition/competition.html• http://www.icarda.org/HomePageStory/Desertification.htm• Princeton Review: AP Biology Exam 2012
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