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 species living in the same area, potentially interacting Community – group of populations of different species living 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 affect distribution, abundance, and evolution.

Types of ecological interactions competition predation parasitism mutualism commensalism symbiosis

Competition – two species share a requirement for a limited resource  reduces fitness of one or both species

Predation – one species feeds on another  enhances fitness of predator but reduces fitness of prey herbivory is a form of predation

Parasitism – one species feeds on another  enhances fitness of parasite but reduces fitness of host

Mutualism – two species provide resources or services to each other  enhances fitness of both species

Commensalism – one species receives a benefit from another species  enhances fitness of one species; no effect on fitness of the other species

Symbiosis – two species live together  can include parasitism, mutualism, and commensalism

Organizing ecological interactions effect on species 1 + 0 - predation herbivory parasitism + - commensalism mutualism effect on species 2 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 Trophic Level – each step in a food chain or food web Biomass Pyramid Energy Pyramid Pyramid of Numbers

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 WATER CYCLE NUTRIENT CYCLES: CARBON CYCLE NITROGEN CYCLE PHOSPHORUS CYCLE

Why are nutrients important ? Every living organism needs nutrients to build tissues and carry out essential life functions. 95% of your body is made of… OXYGEN CARBON HYDROGEN NITROGEN

THE WATER CYCLE

Water Cycle 1 Water Water on land 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 Runoff 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: Biological Geochemical Mixed biochemical 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) in Atmosphere Nitrogen-containing nutrients in the biosphere include: Ammonia (NH3) Nitrate (NO3-) Nitrite (NO2-) ORGANISMS NEED NITROGEN TO MAKE AMINO ACIDS FOR BUILDING PROTEINS!!! N03- & N02- NH3

Nitrogen Cycle 1 Nitrogen fixation Nitrification 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