Ecology

What is Ecology? Ecology is the study of interactions among

organisms and between organisms and their environment.

There are many levels of organization ecologists study…

Levels of Organization

Levels of Organization Species: can breed and produce fertile offspring Population: same species in same area Community: different populations in same area Ecosystem: all organisms (biotic) in particular

place; includes nonliving (abiotic) surroundings Biome: group of ecosystems with same climate

(temperature and precipitation) and similar communities

Biosphere: all portions of the planet where life exists (land, water, air, atmosphere)

Basic Terminology Ecosystem – All the biotic and abiotic factors

in an environment Heat Energy – Form of “lost” energy, 90% of

available energy is lost in the form of heat. Chemical Energy – Glucose transfer in the food

chain Light Energy – Originating source of Energy

from the sun (Main source of energy)

Energy Flow Summary Energy flows in one direction through an

ecosystem, from the sun or inorganic compounds to producers (organisms that can make their own food) through various levels to consumers (organisms that rely on other organisms for food).

Energy Flow Producers: Autotrophs

Photosynthesis Vs. Chemosynthesis Consumers: Heterotrophs

Herbivores Carnivores Omnivores Detritivores Decomposers Scavenger

Trophic Levels

Feeding Relationships

Food chain: series of steps (linear)

Food web: links all food chains together

Trophic level: each step in a chain or web

Ecological Pyramids

Energy PyramidShows the relative amount of energy available at each trophic level. Organisms use about 90percent of this energy for life processes. Only 10% is transferred.

Biomass PyramidRepresents the amount of living organic matter at each trophic level.

Typically, thegreatest biomass is at the base of the pyramid.

Pyramid of Numbers

Shows the relativenumber of individualorganisms at eachtrophic level.

Cycling of Nutrient and Matter

Remember: Energy flows in one direction and matter cycles.

Recycling in the Biosphere Unlike the one-way flow of energy, matter

is recycled. Matter moves through an ecosystem in

biogeochemical cycles. Matter is recycled because systems do not

use up matter, they transform it.

Four Main Cycles Water Cycle Nutrient Cycles

Carbon Cycle Nitrogen Cycle Phosphorus Cycle

Water Cycle 1. When rain falls on the ground, it either soaks

into the soil or runs across the surface of the soil. When rainwater runs across the land, what body of water might collect the rain?

2. From here, where might the water flow? 3. After the rain, the sun comes out and the land

dries. Where does the water that had been on the land go?

Water Cycle Water moves between the ocean, atmosphere, and

land. Steps of the water cycle:

Evaporation Transpiration Condensation Precipitation Runoff Seepage Groundwater

Water Cycle Sketch a simple diagram of the water cycle in your notes.

Nutrient Cycles Every organism needs nutrients to grow

and function. Like water, nutrients are also transferred in cycles.

3 Nutrient Cycles: Carbon Nitrogen Phosphorus-mostly in rocks and soil minerals

Carbon CycleCO2 in

Atmosphere

CO2 in Ocean

Carbon Cycle Four main types of processes move carbon

through its cycle: Biological processes, such as photosynthesis,

respiration, and decomposition, take up and release carbon and oxygen.

Geochemical processes, such as erosion and volcanic activity, release carbon dioxide to the atmosphere and oceans.

Carbon Cycle Mixed biogeochemical processes, such as the

burial and decomposition of dead organisms and their conversion under pressure into coal and petroleum (fossil fuels), store carbon underground.

Human activities, such as mining, cutting and burning forests, and burning fossil fuels, release carbon dioxide into the atmosphere.

Nitrogen CycleN2 in Atmosphere

NH3

NO3-

and NO2-

Nitrogen Cycle Bacteria that live in the soil and on the

roots of legume plants convert nitrogen gas to ammonia through nitrogen fixation.

When organisms die, their ammonia can be converted back to nitrogen gas through denitrification.

Phosphorus Cycle Phosphorus is essential to living organisms because it forms part of

important life-sustaining molecules such as DNA and RNA. Phosphorus remains mostly on land in rock and soil minerals, and in

ocean sediments. It is not very common in the biosphere

phosphorus exists in the form of inorganic phosphate. As the rocks and sediments gradually wear down, phosphate is

released. On land, some of the phosphate washes into rivers and streams,

where it dissolves. The phosphate eventually makes its way to the oceans, where it is

used by marine organisms.

Phosphorus Cycle