Download Ecology

Ecology
The study of relationships
between biotic and abiotic parts
the environment.
1969: EARTHRISE
Big Idea: Biosphere
• Thin life supporting layer on surface of
Earth.
– Hydrosphere: upper
– Atmosphere: lower
– Soil: agrosphere?
Big Idea
• Ecosystems: Life supporting systems
are in nature with biotic and abiotic parts.
– Biotic: LIVING THINGS
– ABIOTIC: NON LIVING THINGS
Big idea
– Carrying capacity: population of critters that an
ecosystem can support
• Abiotic and biotic factors in an ecosystem can affect
the carrying capacity of the environment.
– Example:
• Climate change will affect what populations are
found in different areas--we can measure these
changes happening already
• Introduced species, flying Asian carp displace
native species by reducing the food supply
Big idea
• Energy moves through the environment
– Food chains and food webs model energy
movement in ecosystems
– Energy input--the sun
– Sun producers(plants) consumers(herbivores,
carnivores and decomposers)
– Energy is lost from the system because of
movement, body heat, etc
Big Idea
• Ecologist study
organisms at various
levels of organization:
– Species
– Population
– Community
– Ecosystem
– Biome
– Biosphere
Big Idea
• Biome: Climate region that supports
certain ecosystems
– Determined by: Latitude, altitude, rainfall
– Rainforest, temperate forest, boreal
forest/tiaga, tundra, desert, prairie/steppe,
marine, freshwater, many more.
World Biomes
Ecosystem
• Part of the environment with particular
characteristics.
• Type of environment (DEPENDS ON BIOME)
– Pond (Tundra, Tiaga, temperate, prairie, even
desert!)
– Swamp
– Forest
– Lake
– Desert
– Etc.
Understanding Ecosystems
• Population interrelationships
– Competition
– Predation…
– Mutualism…
• Food chains and food webs
– Producers--consumers--decomposers
• Pyramid graphs of
– Biomass
– Energy
– Population
• Abiotic cycles
– Water
– Carbon
– nitrogen
Why are elements important ?
• Every living organism
needs nutrients to
build tissues and
carry out essential
life functions.
95% of your body is made of…
1)
OXYGEN
2)
CARBON
3)
HYDROGEN
4)
NITROGEN
Many of these cycle in nature.
hydrologic cycle: transfers water and
heat
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Evaporation: liquid to gas
Condensation: gas to liquid (clouds)
Precipitation: rain, snow, dew, frost, fog
Runoff: enters streams, lakes, and
rivers of drainage basins
• Groundwater: water in soil and
underground
• Water table: depth of aquifer
• Aquifer: groundwater storage
Carbon cycle: O2/CO2
• COMBUSTION: BURNING
– CH4 + O2
HEAT + H2O + CO2
• RESPIRATION: ENERGY FOR CELLS
– C6H12O6 + O2
HEAT + H2O + CO2
• PHOTOSYNTHESIS (STORES ENERGY)
– LIGHT + H2O + CO2
C6H12O6 + O2
Nitrogen cycle
• Nitrogen is necessary for DNA and
proteins
• Lots of N2 in the air. Plants can’t use it.
• Nitrification: Nitrogen is added to soil by
decomposition, lightning, and bacteria on
the roots of some plants (legumes and
nitrogen fixing bacteria)
PHOSPHORUS CYCLE
PHOSPHORUS FORMS PART OF IMPORTANT LIFE-SUSTAINING
MOLECULES (ex. DNA & RNA)
Pyramids: 10% rule
• Graphs showing location of energy and
mass in ecosystems.
• Each level is a “trophic” level. Only
10 % of energy moves up each level.
Top carnivore
Secondary consumers: carnivores and omnivores
Primary consumers: herbivores
Producers: plants store energy
TROPHIC PYRAMID
Second law of thermodynamics (entropy)
HIGHER LEVEL PREDATOR (1 KG)
CARNIVORES (10KG)
HERBIVORES (100 KG)
PRIMARY PRODUCERS (1,000 KG)
Ecological Pyramids
• Moving up a food chain, you generally
find fewer individuals at each
successive trophic level.
Food chains and food webs
• Show how energy and biomass moves
through an ecosystem
• Food webs include interrelated food chains
• Trophic levels (energy levels) in food chains
– Sun/energy input
– Producers: make food
– Consumers
• Primary: herbivore
• Secondary: carnivore/omnivore
– Animals use energy for living. So there can’t be
too many levels.
Food Web
Ecosystem: ecological system
• Abiotic parts: energy, H2O, O2, air,
minerals, pollutants, sand, rock…
• Biotic parts: energy, plants, animals,
decomposers
• Community: all the populations in an ecosystem.
Different populations play different roles in the
community--niche.
• Population: members of one species in a
community. Populations affect each other. What
is bad for an individual may be good for the
population.
– Wolf eats a deer
• Habitat: where an organism lives. What part of
the ecosystem supplies the needs of a
population.
• Niche: how an organism lives--its role or job: the
animal that eats spruce cones…
SUCCESSION
• How a community changes or matures
• Depends on biome: limited by climate
• Climax community: most advanced
community in a biome
– Ours is coniferous forest
– South west Minnesota is prairie
• Pioneer species are first plants to grow
• Primary succession: from nuttin’
– Following volcano eruption or flood that leaves no
soil behind
• Secondary succession: after logging or
farming or fire.
Terrestrial Primary Succession
Population dynamics
• Population counts
– Direct count
– Estimate: count a sample
• Sample size matters
• Selection: is the sample representative
• accuracy
• Limits to growth
– Carrying capacity: maximum sustainable population
– Limiting factors
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Predator
Parasites
Competition
Habitat--food, water, etc.
Fluctuations in Populations
HUMAN POPULATION
• CENSUS?
• LIMITING FACTORS?
• CARRYING CAPACITY? Current pop is over 6
billion. 9 BILLION + is the new predicted
maximum maybe 30 years from now.
• BIRTH RATE VS. DEATH RATE
• ZPG: ZERO POPULATION GROWTH
– 2 KIDS/FAMILY: should this be legislated?
– family size is related to affluence and education
LOGISTIC VS. EXPONENTIAL GROWTH
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Population dynamics
Competition
Predator/prey
Parasite/host
Symbiosis -- co-evolution (really close
relationship--dependence)
– Mutualism: both benefit
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Flower and bee
Algae and fungi in lichen
Shark and cleaner wrase (dentist fish)
Sea anemone and clown fish
– Commensalism: one benefits and one doesn’t
know or care…
• Bird nest and tree
• Shark and remora
Competition: species need same
stuff. Nature only tolerates limited
competition.
– Exclusion: “out-compete”--force a species out of a
niche--Asian carp in Mississippi R. and our fish,
humans and every other species on Earth.
– Character displacement: make a species modify
or change it’s niche-- raccoons in your garbage.
• Niches can be fundamental (preferred--what you want),
or realized (what you get).
– Exotic or introduced species create competitive
pressures and lack limiting factors like predators.
Niches: species won’t share
Competition
Review
• Biosphere
• Biome
• Ecosystem
– Biotic
– abiotic
• Community
• Population
• Relationships
– Symbiosis
• Mutualism
• Commensalism
• parasitism
– Predation
– competition
• Cycles
– Oxygen
– Nitrogen
– water
• succession