What is ecology Ecology Ecology scientific study of

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What is ecology?

What is ecology?

Ecology • Ecology = scientific study of the interactions among organisms and between organisms

Ecology • Ecology = scientific study of the interactions among organisms and between organisms and their environment (surroundings) • Each organism plays a role in their “household” (the environment) = ‘niche’ • Interactions produce a web of interdependence between organisms and the environment • The environment and interactions are constantly changing (dynamic)

Levels of Organization-big->small • Biosphere = portions of the planet where all life exists

Levels of Organization-big->small • Biosphere = portions of the planet where all life exists (land, water, air, etc) • Biome = group of ecosystems that have the same climate and similar dominant communities • Ecosystem = collection of all the organisms that live in a particular place together with their nonliving (physical) environment • Communities = different populations that live together in a defined area • Populations = groups of individuals that belong to the same species and live in the same area • Species = group of organisms so similar that they can breed and produce fertile offspring • Individual = one member of a specific species

Figure 3 -2 Ecological Levels of Organization Section 3 -1 Go to Section:

Figure 3 -2 Ecological Levels of Organization Section 3 -1 Go to Section:

Energy flow • Every organism needs energy to power life’s processes • Energy is

Energy flow • Every organism needs energy to power life’s processes • Energy is obtained through interactions with the environment • The flow of energy through an ecosystem is one of the most important factors that determines the system’s capacity to sustain life

Populations • INCREASES– immigration; higher birth rate than death rate • DECREASES– emmigration; higher

Populations • INCREASES– immigration; higher birth rate than death rate • DECREASES– emmigration; higher death rate than birth rate

Producers • Sunlight is the main energy source of life on Earth • Only

Producers • Sunlight is the main energy source of life on Earth • Only plants & certain bacteria can capture energy from sunlight or inorganic chemicals and use that energy to produce food = autotrophs • Autotrophs are also called producers, – Some autotrophs use light energy to convert carbon dioxide & water into oxygen & sugars through the chemical reaction photosynthesis (plants/algae) – Some use chemical energy to produce carbohydrates in absence of light through chemosynthesis (bacteria)

Consumers • Must acquire energy from other organisms = heterotrophs • Heterotrophs are also

Consumers • Must acquire energy from other organisms = heterotrophs • Heterotrophs are also called consumers – Herbivores = eat only plants – Carnivores = eat only animals – Omnivores = eat both plants and animals – Detritivores = eat plant/animal remains and other dead matter called detritus – Decomposers = break down organic matter

Feeding Relationships • Energy flows through an ecosystem in one direction • Energy flows

Feeding Relationships • Energy flows through an ecosystem in one direction • Energy flows from the sun or inorganic compounds to autotrophs (producers) and then to various heterotrophs (consumers)– FOOD CHAIN • Feeding relationships among organisms in an ecosystem usually form a network of complex interactions shown as a food web • Each step in a food chain/web = trophic level

Food Chain

Food Chain

Section 3 -2 Go to Section: Food Web

Section 3 -2 Go to Section: Food Web

Trophic Levels • Each step in a food chain or web is a trophic

Trophic Levels • Each step in a food chain or web is a trophic level. – The first trophic level is the producers. – The second trophic level is the consumers (herbivores). – The third and fourth levels are more consumers (omnivores and the carnivores).

Ecological Pyramids • The amount of energy or matter in each trophic level of

Ecological Pyramids • The amount of energy or matter in each trophic level of a food chain/web of an ecosystem can be represented by an ecological pyramid – Energy pyramid = only about 10% of the energy stored in one trophic level is passed on to the next higher level, because most of the energy is used for life processes and some is released into the environment as heat – Biomass pyramid = potential total amount of living tissue within a given trophic level (grams per unit area) for each trophic level in an ecosystem – Pyramid of numbers = relative number of individual organisms at each trophic level

Ecological Pyramids Section 3 -2 Energy Pyramid Shows the relative amount of energy available

Ecological Pyramids Section 3 -2 Energy Pyramid Shows the relative amount of energy available at each trophic level. Organisms use about 10 percent of this energy for life processes. The rest is lost as heat. Biomass Pyramid Represents the amount of living organic matter at each trophic level. Typically, the greatest biomass is at the base of the pyramid. Go to Section: Pyramid of Numbers Shows the relative number of individual organisms at each trophic level.