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Principles of Ecology
Biology
What is Ecology?
– What is the lowest level of organization that most ecologists study?
– What name is given to several organisms in the same species interacting together?
– What factors are included in an ecosystem that are not included in a community?
– Describe how ecosystems and biomes differ? – Which level of biological organization is the
most complex?
What is Ecology?
– What is the lowest level of organization that most ecologists study? organism
– What name is given to several organisms in the same species interacting together? population
– What factors are included in an ecosystem that are not included in a community? Abiotic factors
– Describe how ecosystems and biomes differ? Biomes include several ecosystems over a large area.
– Which level of biological organization is the most complex? Biosphere
Levels of Organization
• Ecologist study organisms ranging from the various levels of organization:– Species– Population– Community– Ecosystem– Biome– Biosphere
Interrelationships
• Define the 3 categories of symbiosis and give an example of each – and record in your journal/notebook
• What is competition? Give an example.• What is predation? Give an example
Population – group of individuals of the same speciesliving in the same area, potentially interacting
Community – group of populations of different speciesliving in the same area, potentially interacting
What are some ecological interactions?
Why are ecological interactions important?
Interactions can affect distribution and abundance.
Interactions can influence evolution.
Think about how the following interactions can affectdistribution, abundance, and evolution.
Types of ecological interactions
competition
predation
parasitism
mutualism
commensalism
symbiosis
Competition – two species share a requirement for alimited resource reduces fitness of one or both species
Predation – one species feeds on another enhancesfitness of predator but reduces fitness of prey
herbivory is a form ofpredation
Parasitism – one species feeds on another enhancesfitness of parasite but reduces fitness of host
Mutualism – two species provide resources or servicesto each other enhances fitness of both species
Commensalism – one species receives a benefit fromanother species enhances fitness of one species; noeffect on fitness of the other species
Symbiosis – two species live together can includeparasitism, mutualism, and commensalism
Organizing ecological interactions
effect on species 1
effect onspecies 2
+ 0 -
+
0
-
mutualism
predationherbivoryparasitism
predationherbivoryparasitism
commensalism
commensalism
competition
competition
competition
Ecosystem Interactions
• What is a habitat?
• What is a niche?
Flow of Energy in an Ecosystem
• What are: autotrophs, heterotrophs, herbivore, carnivore, omnivores, detritivores
• What is the main energy source for life? • What is a trophic level? • How do you draw a food chain, food web?
What is the difference?• What group is at the top of the pyramid of
energy, biomass, numbers?
How does Energy flow through an Ecosystem?
• Energy flows through an ecosystem in ONE direction, – sun or chemicals
– Autotrophs
– heterotrophs
Energy Flow in Ecosystems:
Feeding Relationships
• Food Chain – steps of organisms transferring energy by eating & being eaten
• Food Web – network of all the food chains in an ecosystem
Food Web
Ecological Pyramids
Energy Pyramid
Biomass Pyramid
Pyramid of Numbers
• Trophic Level – each step in a food chain or food web
How does Matter move through an ecosystem?
• Unlike the one way flow of energy, matter is recycled within & between ecosystems
• Nutrients are passed between organisms & the environment through biogeochemical cycles
• Biogeochemical Cycles:– Bio –life– Geo – Earth– Chemo – chemical
1. WATER CYCLE
2. NUTRIENT CYCLES:
a) CARBON CYCLE
b) NITROGEN CYCLE
c) PHOSPHORUS CYCLE
Why are nutrients important ?
95% of your body is made of…1) OXYGEN
2) CARBON
3) HYDROGEN
4) NITROGEN
• Every living organism needs nutrients to build tissues and carry out essential life functions.
THE WATER CYCLE
Water Cycle 1
• Water – enters atmosphere by evaporation, transpiration – leaves atmosphere as precipitation
• Water on land– filters through ground– runs off to lakes, rivers, ocean
Water Cycle 2
• Aquifers – underground caverns, porous layers of rock– store groundwater
• Runoff – movement of surface water from land to
ocean
CARBON CYCLE (see fig.3-13)
4 PROCESSES MOVE CARBON THROUGH ITS CYCLE:
1) Biological
2) Geochemical
3) Mixed biochemical
4) Human Activity
CO2
CO2
Carbon Cycle
• CO2 gas enters plants, algae, cyanobacteria
– photosynthesis turns CO2 into organic molecules
• Cellular respiration, combustion, erosion of limestone return CO2 to water, atmosphere
– where it is again available to producers
NITROGEN CYCLE (see fig.3-14)
Nitrogen-containing nutrients in the biosphere include:
1) Ammonia (NH3)
2) Nitrate (NO3-)
3) Nitrite (NO2-)
ORGANISMS NEED NITROGEN TO MAKE
AMINO ACIDS FOR BUILDING PROTEINS!!!
N2 in Atmosphere
NH3
N03- &
N02-
Nitrogen Cycle 1
• Nitrogen fixation – conversion of nitrogen gas to ammonia
• Nitrification – conversion of ammonia or ammonium to nitrate
Nitrogen Cycle 2
• Assimilation – conversion of nitrates, ammonia, or ammonium
to proteins, chlorophyll, or nitrogen-containing compounds (by plants)
– conversion of plant proteins into animal proteins
Nitrogen Fixation
PHOSPHORUS CYCLE (see fig.3-15)
PHOSPHORUS FORMS PART OF IMPORTANT LIFE-SUSTAINING MOLECULES (ex. DNA & RNA)
Phosphorus Cycle 1
• Phosphorus erodes from rock
• Plants absorb inorganic phosphate from soil (through roots)
• Animals obtain phosphorus from their diets
Phosphorus Cycle 2
• Decomposers release inorganic phosphate into environment
• Phosphorus washes into ocean– is deposited in seabeds– lost from biological cycles for millions of years