Download Ecology2

Ecology
Ecology Definition
• Study of the relationships between
organisms AND organism and their
environment
Levels of Organization
• Population
– All members of a species living in a given
location
What affects population size?
• Density Independent Factors
– Independent of # of individuals
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drought
freezes
hurricane
floods
forest fires
Tsunami
Volcano eruptions
What affects population size?
• Density Dependent Factors
– Dependent on the # of individuals
• Intraspecific competition
• Interspecific competition
– Compete for ecological niche (food, living space)
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Lower birth rate
Migration (high density forces people to move)
Predation (high density, easier to catch a member)
Parasitism (High density, easier transmission)
Population Growth
• Exponential Growth
– constant birth rate
– never limited by food or disease,
– birth rate alone controls how fast (or slow) the
population grows
Population Growth
• Logistic Growth
– food and disease as
“limiting factors”
– limit to the number of
individuals the
environment can
support. (“Carrying
Capacity”)
– Population shows
logistic growth.
Population Growth Strategies
• Population Growth
Population Growth Strategies
R Unstable environment, density
independent
K Stable environment, density
dependent interactions
• small size of organism
• energy used to make each individual is
low
• many offspring are produced
• early maturity
• short life expectancy
• each individual reproduces only once
• type III survivorship pattern
in which most of the individuals die
within a short time
but a few live much longer
•large size of organism
•energy used to make each
individual is high
•few offspring are produced
•late maturity, often after a prolonged
period of parental care
•long life expectancy
•individuals can reproduce more
than once in their lifetime
•type I or II survivorship pattern
in which most individuals live to near
the maximum life span
Back to levels of organization
• Community
– All interacting populations in a given location
• Ecosystem
– Community PLUS physical environment
• Biosphere
– Portion of Earth in which life exists
Requirements of Ecosystems
• Constant flow of energy into system
• Sun to plants to all others
• Cycle of materials between living
organisms and the environment
Components of Ecosystems
• Biotic Factors
– Plants, animals, fungi, bacteria, protozoa
• Abiotic Factors
– Light, temperature, water, minerals, oxygen,
Carbon dioxide, Nitrogen, pH
How do Biotic Factors Interact?
• Nutritional Relationships (the transfer of
nutrients from one organism to another)
– Autotrophs
– Heterotrophs
• Saprophytes=live of dead organism matter
(mushrooms & other Fungi, some bacteria)
• Herbivores
• Carnivore
– Scavenger (ex. Vulture, Laughing Hyena)
– Predator (ex. Lion)
• Omnivore
How do Biotic Factors Interact?
• Symbiotic Relationships (Living
Relationships between organisms)
– Commensalism
How do Biotic Factors Interact?
– Mutualism
How do Biotic Factors Interact?
– Parasitism
How do we depict Energy Flow?
• Food Chain
Decomposers
get everyone!
How do we depict Energy Flow?
• Food Webs
More realistic than food chain
Classification of “Eaters”
• Filter Feeders
• Herbivores
• Predators
• Parasites
• Detritivores
Energy Pyramid
Biomass Pyramid
Materials Cycles
• Carbon-Oxygen Cycle
CO2 also from
Burning and Decay
Materials Cycles
• Water Cycle
Transpiration
Respiration
Nitrogen Cycle
Nitrogen Cycle
• Decomposing Bacteria and Fungi
– Convert the dead to Ammonia (NH3)
• Nitrifying Bacteria
– Convert Ammonia to Nitrites (NO2) and then to Nitrates
(NO3)- (ie. Plant Fertilizer)
• Nitrogen-Fixing Bacteria (In roots of
legumes=peas, bean plants)
– Convert atmospheric N2 to Ammonia (NH3)
• Denitrifying Bacteria
– Convert Nitrates to atmospheric N2
How do Ecosystems Form?
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Ecological Succession
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Development of area with Pioneer Organisms (Lichen)
Gradual development of more complex ecosystem
Reach a stable Climax community or Biome
Biomes
• Aquatic Biomes
– Largest of all Earth’s Ecosystems
– 70% of Earth water
– Most stable-Why?
– Marine
– Freshwater
– Brackish
Marine Biome
Marine Intertidal Zone
Marine Photic to Aphotic Zones
• Deep sea fish
Freshwater Biomes
• River
• Stream
• Lake (large+deep)
• Pond (shallow)
Freshwater Biomes
• Marsh
– freq. flooding, shallow, few
trees
• Swamp
– low wetland, more open water
compared to marsh shrubs+trees
• Bogs
– shallow, moss, insectivorous
plants
Brackish Water
• Estuary
– Rivers meet
Ocean
– Osmoregulators
vs.
Osmoconformers
Terrestrial biomes
Terrestrial Biomes
• Tundra
– Permanent frozen subsoil
– Lichen, moss, grass
– Snowy owl, caribou
• Taiga
– Long bad winters
– Soil thaws in summer
– Conifers (Pine, Spruce, Fir)
– Moose, black bear
Terrestrial Biomes
• Temperate Deciduous
Forest
– Moderate precip., cold winters,
warm summers
– Deciduous trees (drop leavesmaple,oak,)
– Fox, deer, squirrel
• Tropical Rain Forest
(Extreme Biodiversity)
– Heavy rain, constant warmth
– Broad leaved plants
– Snakes, monkeys, leopards
Terrestrial Biomes
• Grassland
– Variable rainfall, variable temps,
prevailing winds
– Many grasses and wildflowers
– Pronghorn antelope, prairie dogs,
bison
• Desert
– Little rain, extreme temp
fluctuations
– Drought-resistant shrubs and
succulent plants
Terrestrial Biomes
• Savanna
– Grasses, few trees,
water conserving plants
– Warm all year
– Zebra, water buffalo,
lions, hyena
• Chaparral
– Mild winter, very hot
summers
– Prone to fires
– Drought resistant shrubs
Terrestrial Biomes (Latitude vs.
Altitude)
Human and the Environment
Negative Impact
• Urbanization
• Over-farming
resulting in soil
erosion
• Over grazing resulting
in soil erosion
• Use of pesticides
– DDT and the Bald
Eagles’ eggs
(Biomagnification)
• Pollution
Negative Impact
– Water
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PCBs and General Electric
Eutrophication
Thermal pollution
Oil spills
– Air
• Carbon dioxide and Global Warming
• CFCs and Ozone layer hole
• Acid Rain from sulfur and nitrogen compounds
with water vapor
• Ground level ozone from exhaust reacting with
sunlight
– Ground
• Dumps and landfills
• Lead and Mercury Waste Problem
• Nuclear Waste Problem
Negative Impact
• Technological Oversights
• Importation of Pests
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Rabbits in Australia
Lampreys in US
Gypsy Moth and Hardwood Trees
Killer Bees
Japanese Beetles and fruits,lawns and flowers
• Loss of Rainforest
– Affects climate
– Reduce Biodiversity
• Dams
Positive Things
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Recycling
Pollution Control Laws
Cover Crops
Crop Rotation
Windbreaks
Contour Farming
Reforestation
Conservation of Resources
Biological control
Terracing
Biomediation