Ecosystems

Primary Vocabulary Terms

o Ecosystemo Biomasso Law of Conservation of

Energyo Law of Conservation of

Mattero Trophic levelso Detritus

o Producerso Consumers (primary,

secondary, tertiary)o Omnivoreso Detritovores

(Decomposers) o Calorie

Additional Vocabulary Terms

o Ecologyo Trophic levelso Herbivoreso Carnivoreo Omnivoreso Chemotrophso Phototrophs

o Photosynthesiso Cellular Respirationo Chemosynthesiso How energy flows

through an ecosystemo Ecological pyramid

(numbers, biomass, energy)

Overview of 8-3 Ecosystems

o Ecosystemo Classification of Organisms in an

Ecosystem• Trophic levels

o Biomasso Flow of Energy Through Ecosystems

• Producers, Consumers & Decomposers• Ecological Pyramid• Ecosystem Productivity

Ecologyo Ecology• “eco” house & “logy” study of• The study of interactions among and

between organisms in their abiotic environment

• Broadest field in biologyo Biotic-

• living environment• Includes all organisms

o Abiotic- • non living or physical environment• Includes living space, sunlight, soil,

precipitation, etc.

Ecology

o Biology is very organized

o Ecologists are interested in the levels of life above that of organism

Ecosystems

o Ecosystem• All the organisms (living things) in a

given area and the abiotic (physical, non-living) environment

• Organisms and abiotic features interact in an ecosystem

• Ecosystems can vary in size • Ecosystems can overlap and organisms

can move between ecosystems

Biotic Features

o Biotic Features• All the living things in a given area,

include:• Species

• A group of similar organisms whose members freely interbreed and produce fertile offspring

• Population• A group of organisms of the same species that

occupy that live in the same area at the same time

• Community• Al the populations of different species that live

and interact in the same area at the same time

Abiotic Features

o Abiotic Features• All the non-living things in a given area,

include:• Weather• Water• Topography• Nutrients• Physical features• Atmosphere

Thermodynamics

o Study of energy and its transformationso System- the object being studied

• Closed System- Does not exchange energy with surroundings (rare in nature)

• Open System- exchanges energy with surroundings

Law of Conservation of Energy

o Energy cannot be created or destroyed; it can change from one form to another• Ex: organisms cannot create energy they

need to survive- they must capture it from another source

o Also known as the 1st Law of Thermodynamics

Law of Conservation of Energy

o However, • When energy is converted form one form to

another, some of it is degraded to heato Also known as the 2nd Law of

Thermodynamics

Law of Conservation of Matter

o Matter cannot be created or destroyed; it can change from one form to another• Ex: plants convert carbon dioxide and

water into glucose and oxygen

Solar Energy

Energy Reactions in an Ecosystem

o Photosynthesis or Chemosynthesis – transform solar energy or chemical energy from inorganic substances into chemical energy that living things can use

o Respiration - releases energy trapped by photosynthesis or chemosynthesis in the cells of living things to do biological work

Photosynthesis

o Biological process by which energy from the sun (radiant energy) is transformed into chemical energy of sugar molecules

o Energy captured by plants via photosynthesis is transferred to the organisms that eat the plants

6 CO2 + 12 H2O + radiant energy

C6H12O6 + 6 H2O + 6 O2

Cellular Respiration

o The process where the chemical energy captured in photosynthesis is released within cells of plants and animals

o This energy is then used for biological work• Creating new cells, reproduction,

movement, etc.

C6H12O6 + 6 O2 + 6 H2O

6 CO2 + 12 H2O + energy

Trophic Levels

o Trophic Level- includes a group of organisms that obtain food in a similar manner• Producers• Herbivores• Carnivores• Omnivores• Detritivores

Energy Flow

o Passage of energy in a one-way direction through an ecosystem• Producers• Primary

consumers• Secondary

consumers• Decomposers

Food Chains- The Path of Energy Flow

o Energy from food passes from one organisms to another• Each “link” is called a trophic level

Food webs represent interlocking food chains that connect all organisms in an

ecosystem

Flow of nutrients in an ecosystem

Ecological Pyramids

o Graphically represent the relative energy value of each trophic level• Important feature is that large amount of

energy are lost between trophic levels to heat

o Three main types• Pyramid of numbers• Pyramid of biomass• Pyramid of energy

Pyramid of Numberso Illustrates the number of organisms at

each trophic level• Usually, organisms at the base of the

pyramid are more numerous• Fewer organisms

occupy each successive level

o Do not indicate the biomass of the organisms at each level or the amount of energy transferred between levels

Pyramid of Biomasso Illustrates the total biomass at each

successive trophic level• Biomass: measure of the total amt of living

material (dry material)o Illustrates a

progressive reduction in biomass through trophic levels

Biomass of a trophic level

Not consumed consumed

Digested

Body building growth

Gained by the next

trophic level

Released as:

Heat Inorganic nutrients

Undigested

Undigested fecal waste

Trophic detritus

o Only uses samples from populations, so difficult to measure biomass exactly.

o Time of year that biomass is measured affects the result.

o Organisms of the same size do not necessarily have the same energy content.

Pyramid of Energyo Illustrates how much energy is present at

each trophic level and how much is transferred to the next level• Most energy dissipates between trophic

levelso Explains why there are so few trophic levels• Energy levels get

too low to support life

Energy of a trophic level

utilized

Producing food

Growth and development including regeneration

Not utilized about 10% for animals and 20% for plants

Stored as flesh (becomes part of the biomass)

Available for the next trophic level

10% Law of Energy Transfer (Lindemann 1942)

During the transfer of energy from organic food from one trophic level to the next, only about ten percent of the of energy from organic matter is stored as flesh.

The remaining is lost during transfer, broken down in respiration, or lost to incomplete digestion by higher trophic levels.

Only 10% of energy at a particular trophic level is incorporated to the next trophic level. Rapid loss of energy explains why food chain rarely has 5 links.

General pyramid trends

o A healthy ecosystem will always have the most energy available in the first trophic level.

o The number of trophic levels are limited. At each trophic level, there is a dramatic reduction in energy.

o Eating at lower trophic levels means more resources available.

QUICK REVIEW!

All organisms in an ecosystem need _______ from food to live. An energy ________ shows how much food energy is passed from one ________ to another through food chains. __________ have the largest spot at the base of the pyramid. Altogether, only about _____ of the food energy at each level gets passed up to the next level.

energypyrami

d

Producers 10%

organism