Intro to Ecology

Chapter 18

Cellular Organization

Levels of Ecological Organization

Levels Smallest to largestCells Tissues Organs

Organ Systems Organism Population Community Ecosystem

Biosphere

Interdependence

Species interact with both other species and their nonliving environment

Levels of organizationPopulation- Includes members of a

single species that live in one place at one time.

Community- All the interacting organisms living in an area. Example: Fish, Turtles, plants, algae living in a pond together.

EcosystemEcosystem- includes all of the organisms and the nonliving aspects found in a particular place.

Example: Fish, Turtle, plants, water, sunlight.

The Biosphere

The broadest, most inclusive level of organization is the biosphere, the volume of Earth and its atmosphere that supports life.

Biotic vs. Abiotic FactorsBiotic- All living things that

affect an organism. (living components of the environment)

Abiotic- Nonliving factors.(physical and chemical characteristics of environment)

Examples are climate, water, sunlight, and pH.

BIOTIC OR ABIOTIC?? QUIZ:Tree? Oxygen?Cotton Shirt? Rain?Rabbit? Grass?Dead squirrel? Clouds?Owl Pellets? Bones?Steak? Leather?

Organisms in a changing environmentAcclimation

Some organisms can adjust their tolerance to abiotic factors through the process of acclimation

Organisms in a changing environment cont…

Conformers are organisms that do not regulate their internal conditions; they change as their external environment changes.

Regulators use energy to control some of their internal conditions. (homeostasis)

Organisms in a changing environment cont…Escape from Unsuitable ConditionsSome species survive

unfavorable environmental conditions by becoming dormant or by migrating.

Dormant Grass

Birds migrating

NicheAn organism’s niche is its way of

life or its role in its ecosystem.

Generalist-broad niches (oppossum)

Specialist- narrow niches. (koala)

Niche

ProducersMost producers are

photosynthetic and make carbohydrates by using energy from the sun.

AutotrophsExample: trees, plants, algae

Producers Cont…Gross primary productivity the rate producers in an ecosystem capture the energy of sunlight by producing organic compounds.

The rate biomass accumulates is called net primary productivity.

ConsumersConsumers obtain energy by

eating other organisms and include herbivores, omnivores, carnivores, detritivores, and decomposers.

Consumers are heterotrophs

Types of ConsumersHerbivore- eats only

producers (eats plants)Carnivore- eats only

consumers (eats animals)Omnivore- eats both

producers and consumers (eats animals and plants)

Detritivores- eats dead or decomposing material

Energy FlowFood Chains and Food Webs

A single pathway of energy transfer is a food chain.

A network showing all paths of energy transfer is a food web

Food Chain

Food Web

Energy TransferEcosystems contain only a few trophic levels because there is a low rate of energy transfer between each level

Energy TransferOn average 10% of energy is

transferred from one trophic level to the next.

The lower the tropic level the higher percent of energy available.

Energy TransferOrganisms at the lower levels are usually much more abundant than higher levels.

(1000 Zebras/ 1 Lion)

Water CycleKey processes in the water cycle

are evaporation, condensation, and precipitation.

Transpiration- the process of water evaporating from leaves of plants.

Water Cycle

Carbon CyclePhotosynthesis and cellular

respiration are the two main steps in the carbon cycle.

Burning fossil fuels releases carbon dioxide into the atmosphere.

Carbon Cycle

Nitrogen CycleNitrogen-fixing bacteria live in

soil and plant roots.This bacteria is important in the

nitrogen cycle because they change nitrogen gas into a usable form of nitrogen for plants.

The process of converting nitrogen gas to nitrate is called nitrogen fixation.

Recycling NitrogenDecomposers break down bodies of

dead organisms and urine to release the nitrogen they contain as ammonia, this process is known as ammonification.

The soil bacteria take the ammonia and then oxidize it into nitrates, this process is known as Nitrification.

Denitrifying bacteria then break down the nitrates and release the nitrogen to the atmosphere, this process in known at denitrification.

Nitrogen Cycle

Phosphorous CycleIn the phosphorus cycle,

phosphorus moves from phosphate deposited in rock, to the soil, plants absorb it through their roots, then passes to other living organisms, and finally to the ocean.