Topic 1: What is Ecology?
• Defined: Studying how life interacts within the biosphere is called Ecology
• All life interacts within the biosphere– Area within the deepest ocean trenches to the
highest mountains
• Defined: Group of one species living in the same area• Population changes based on:
– Births, Deaths, Immigration, Emigration, Available resources
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Populations
Limiting Factors• Defined: Factors
that control population sizes– Disease, food,
predators, climate, space, mates
• Carrying Capacity: greatest number of individuals that a population can sustain
• What stage is the human population in?
Communities
• Defined: Populations of many species living in the same area at the same time
• Each organism has it own HABITAT– Habitat: Place where an organism lives
• Each species has its own NICHE– Niche: The role/needs of a species– Ex: Termites return nutrients to the soil
Ecosystems
• Defined: Community of species interacting with the living & non-living
• Desert Biotic Factors:– Animals: Mice, Reptiles, Insects– Plants: Cactus, Flowers, Shrubs
• Desert Abiotic Factors: Sand, rocks, sunlight• Ecosystem changes affect biodiversity
– Keystone species greatly alter ecosystems
What is a Biome?• Defined:
Large area with distinct climate, plant, and animal life
• Climate factors: sun, rain, topography
• Climate determines life
Part 2: Ecosystem Components• Producers
– Basis of an ecosystem’s energy
– Autotrophs: perform photosynthesis to make sugars
– Chemotrophs: Bacteria which use minerals from deep-sea vents to make energy
• Consumers– Heterotrophs: Consumes
others for energy– Omnivores, herbivores,
carnivores, decomposers
• Defined: Feeding level of an ecosystem
• Trophic levels consist of producers, consumers, and decomposers
• ~10% of energy is passed to the next level– Few trophic levels45,897 kcal
4589.7 kcal
458.97 kcal
45.897 kcal
4.5897 kcal
• Defined: Organisms that create their energy through photosynthesis–AKA: Autotrophs–Convert sunlight into
glucose (sugar)• Bottom of food chain
(1st trophic level)• Ex: Plants, Algae,
Cyanobacteria
• Primary Consumers– Feed directly on
producers– Herbivores
• Secondary Consumers– Feed on primary
consumers– Carnivores & omnivores
• Tertiary Consumers– Feed on secondary
consumers– Carnivores & omnivores
• Quaternary Consumers– Feed on tertiary
consumers– Carnivores & omnivores
• Decomposers: break down dead matter into simpler substances
• Returns nutrients to the soil
• Feed on any trophic level
Name the tropic levels in this food pyramid
• Defined: Group of interrelated food chains
• Arrows show direction energy (nutrients) travel
producer
Primary consumer
Secondary consumer
Tertiary consumer
producer
Primary consumer
Secondary consumer
Tertiary consumer
Quaternary consumer
Topic 3: Succession
Primary Succession
• Defined: Establishment and development of an ecosystem in an uninhabited environment
• Volcanic lava creates new land• Glaciers retreating exposing new land
Bare Rock
• Lava cools and hardens into rock
Pioneer Species
• Defined: First organisms to inhabit new land• Moss and lichen grow on bare rock• Dead matter accumulates with rock pieces
– Thin soil layer begins to accumulate
The Process Continues
• Seeds enter the area and grow• Small flowers & shrubs accumulate more
organic matter• With new plants, small animals inhabit the
area
The Process Continues
• Small trees take root in the accumulated organic matter
• More animals use the trees as a habitat
Climax Community
• Large trees take root– Overcrowd and out-compete original trees
• New animals inhabit new forests
Secondary Succession
• Changes that take place after a disturbance occurs in an established ecosystem– Forest fires, floods, tree falls…
• Faster scale (soil preexists)
Topic 4: Biogeochemical Cycles
Oxygen Cycle
• Autotrophs: Release O2 into atmosphere via photosynthesis• All life: Absorbs O2 to be used during cellular respiration
– Respiration: creates ATP energy for cells
O2
O2
Carbon Cycle
• Carbon = (organic molecules) carbohydrates, proteins, lipids, nucleic acids
• Plants & autotrophs:– Intake: Absorb CO2 from atmosphere– Output: Create carbohydrates by photosynthesis
CO2
CO2
sugars
Carbon Cycle
• Consumers– Intake: Carbon moves up the food chain as 1 feeds on another– Output: Release CO2 during respiration
CO2
CO2
sugars
Carbon Cycle
• Decomposers– Input: Feed on dead organic matter– Output: Release CO2 during respiration– Output: Organic molecules returned to soil during decomposition
C C
C
sugars
Carbon Cycle
• Human Industry– Output: Release CO2 into atmosphere when fossil fuels
(coal, oil, natural gas) are burned
CO2
Nitrogen Cycle
• N = 78% atmosphere (most unusable)• Soil Bacteria
– Nitrogen fixation: convert atmospheric nitrogen into ammonia– Nitrification: ammonia converted into nitrates
N2
Ammonia Nitrates
Nitrogen Cycle
• Plants– Absorb nitrates through their roots
Nitrates
Nitrogen Cycle
• Animals– Ingest nitrates through the food chain (plants eaten)
Nitrates
Nitrogen Cycle
• Decomposers– Feed on dead organisms– Return ammonia to soil by feeding on dead matter
Ammonia
Ammonia
Ammonia
NitratesNitrates
Phosphorus (P) Cycle• No
phosphorus in atmosphere
• Rocks– Phosphorus
released by weathering of rocksPP
Phosphorus (P) Cycle
• Plants– Absorb P
into their roots
P
Phosphorus (P) Cycle
• Animals– Ingest P
when plants eaten
– P continues to move up food chain
P
Phosphorus (P) Cycle• Decomposers
– Breakdown dead matter and release P into soil
PP
Phosphorus (P) Cycle
• Human Contribution– Adding
excess P from fertilizers
– P washes into lakes, etc…
– Excess P causes extreme algae growth
PP
P P
PP
Topic 5: Community Interactions• when organisms live together in an ecological
community they interact constantly.
• Three types of interactions– Competition– Predation– Symbiosis
Competition• occurs due to limited
resources– water, nutrients, light,
food.
• Competitive exclusion principle - no two species can occupy the same niche in the same habitat at the same time
Competition
Predation• Predation- when an
organism captures and feeds on another organism.
• Predator- hunter• Prey- hunted
Symbiosis• Symbiosis- any relationship where two
species live closely together. (3 types)– Mutualism– Commensalism– Parasitism
Symbiosis• Mutualism - both
species benefit from a relationship– Flower: gets pollinated– Moth: gets nectar
Mutualism example:Cleaner birds and Crocodiles
Symbiosis• Commensalism – One
member of a symbiotic relationship benefits and the other is neither helped or harmed– Anemone: gains nothing– Fish: protection
Symbiosis• Parasitism- One
creature benefits and one creature is harmed– Insect larvae will feed on
the caterpillar
Topic 6: Environmental Issues
Ozone Layer Depletion• Ozone Function:
Block UV radiation from sun
• Problems:– CFCs thinning the
ozone layer– More UV radiation
reaches the surface• Effects: Crop damage,
skin cancers, Eye damage
• Solution: Reduce CFCs, regrow trees
UV
Ozone layerOzone layer
CFCs
UV
The Greenhouse Effect• G.H.E. is naturally good
(it warms Earth)• Problem: Excess heat
trapped near the earth’s surface
• Fear: Climate patterns change, ice caps melt
• Main Cause: CO2 from burning of fossil fuels (coal, oil, natural gas)
• Solutions: Reduce use of fossil fuels, regrow trees, alternative energy sources
What’s in a name?
The purpose of a greenhouse is to trap heat year round
Earth
heat
heat
heat
Some heat escapes into space
Some heat naturally trapped by Earth’s atmosphere
Earth
EarthExcess CO2 in atmosphere
Less heat escapes into space
More heat trapped near Earth’s surface
The Greenhouse Effect is naturally GOOD!
Mars: No Greenhouse Effect
Little heat is trapped by the thin CO2 atmosphere. High temperatures can be around 20⁰F.
Earth: Balanced Greenhouse Effect
Average global temperature is 57⁰F.
Venus: The Extreme Greenhouse Effect
Heat is trapped by the thick CO2 atmosphere. Temperatures reach 750⁰F.
Deforestation• Defined: Clearing of
forested areas• Reasons:
– High demand for wood products
– Create farmland
• Problems:– Species lost– Excess CO2 released
• Solutions:– Recycle– Improved farming
techniques
The Smog and Ground-Level Ozone• Reason:
– Burning of fossil fuels & industry
• Problems:– Respiratory illness– Ozone gas is poisonous
• Causes:– Particulates rise into air
and react with sunlight to make air pollution
• Solutions:– Reduce use of fossil fuels– alternative energy sources– Plant trees
Non-native Species Introduction• Defined: Foreign organisms
are introduced to a new habitat• Reason:
– Pet industry, “free ride” organisms, pest control
• Effects:– Foreign species outcompete
native species– Food webs unbalanced– Economic damage
• Solutions:– Laws preventing foreign
goods into new countries– Introduce predators
Zebra mussels
Kudzu vines
• Defined: Precipitation with a below normal pH
• Cause:– Fossil fuel pollution rises
into the air & then falls as rain
• Effect:– Waterways more acidic– Kills plant and animal life
• Solutions:– Reduce fossil fuel usage– Add buffer (base) to
waterways
The Big Problem: Overpopulation• Over 6.7 billion people• Many natural resources
are nonrenewable– Fossil fuels take
millions of years to form• More people means:
– 1) More forests removed
– 2) More resources consumed
– 3) More CO2 released
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