IB ESS Topics 2.2, 2.3 & 1.3

A group of organisms that are capable of interbreeding

and have fertile offspring

A group of organisms of the same species living in the same area at the same time

A group of populations living and interacting with each other in a common habitat. It involves biotic interactions only

A community of interdependent organisms and the physical environment they inhabit. It includes the interactions of communities with the abiotic habitat

The part of the Earth inhabited by organisms. It extends from the atmosphere to the Earth's crust

Make their own food from compounds found in environment. All other organisms depend one way or another on biomass that was assimilated by producers.

Consists of herbivores (primary consumers), carnivores (secondary or higher level consumers) and omnivores (plant and meat eaters). Consumers either directly or indirectly (several steps removed) gain energy from the producer level. About 10% of the energy from one trophic level is passed on to the next level

Organisms that feed off of dead and decomposing organic material. They recycle organic matter by biodegrading detritus to get their nutrients. They then release simple inorganics into the environment for use by producers

Process by which living organisms integrate nutrients from external resources to their body

Total mass of living organisms in a given area

Consumers that eat other animals

Consumers that eat both plants and animals

Consumers that eat only plants

Carbon dioxide, water, chlorophyll, and light

Sugars gained through photosynthesis or feeding are used to provide energy during respiration

Process of cellular respiration that occurs in the absence of oxygen, leading to the breakdown of glucose into energy and producing lactic acid or ethanol as a byproduct

The break down of organic material in a landfill relies on anaerobic respiration

The rate at which energy is added to the bodies of a group of organisms in the form of biomass

The rate at which solar energy (sunlight) is converted into organic compounds via photosynthesis (producers). Measured in units of energy per unit area per unit time.

The total gain in energy; total biomass produced

the gross productivity specifically of producers. It is the total rate of photosynthesis in a given area.

Amount of light, CO2 and H2O available, nutrient availability, temperature, and herbivory

the rate of oxygen production, CO2 consumption rate & glucose production rate

the rate of energy storage by photosynthesizers in a given area after subtracting the energy lost to respiration

NPP = Photosynthesis (GPP) - Respiration (R)

Loss in biomass

Growth, gain in biomass

No change

• CO2 Assimilation (use probe to measure GP and to measure the amount of CO2 released during R)

• O2 production

1. 25,000 kcal/m2/yr

2. 55,000 kcal/m2/yr

3. -25,000 kcal/m2/yr

4. -55,000 cal/m2/yr

1. 6,000 kcal/m2/yr

2. 18,000 kcal/m2/yr

3. -6,000 kcal/m2/yr

4. 12,000 kcal/m2/yr

equal to the NP of the trophic group before it

• Producer: GPP - R = NPP

GSP is the total energy or biomass assimilated by consumers

GSP = food eaten - fecal loss

NSP = GSP - R

Show the feeding relationships with multiple species per trophic level and multiple energy pathways (multiple arrows).

Show one feeding interaction that depicts how one species per trophic level gets energy from the previous level. It depicts one energy arrow per trophic level.

Is the position an organism occupies in a food chain. In a food web, omnivores may occupy more than one trophic level.

Is the position an organism occupies in a food chain. In a food web, omnivores may occupy more than one trophic level.

Energy cannot be created or destroyed but it may be changed to other forms.

Energy is always degraded (lost to an unwanted form) during a transfer of energy. This means the entropy of the universe is always increasing.

Compares the number of organisms at each trophic level

Compares the mass of biological material at each trophic level

Compares the amount of energy passing through each trophic level over a period of time

1. Producer is large in size--Leads to inverted pyramid of numbers

   1. Ex. 1 tree may support many small primary consumers

2. Seasonal Changes

   1. Ex. After a seasonal fire, a grassland has less biomass in the producer level

3. Reproduction/Migration/Feeding Habits

   1. Ex. When a meadow blooms it attracts a large number of pollinators who may not always stay in that area

the process in which a non-biodegradable toxin that has been released into the environment ends up stored in the body tissue of an organism

the process in which a non-biodegradable toxin becomes more concentrated in higher trophic level organisms.

In the environment, insects would encounter DDT and absorb some of it into their bodies. Often, they would receive a sub-lethal dose, enough to impair them but perhaps not kill them. In any event, it stands to reason that insects either dying or merely slowed down by pesticide intake would become easy targets for birds. Upon ingestion, the DDT in the insect bodies is released and makes its way into the tissues of the bird's body, particularly the fat deposits. Because an individual bird eats many insects, and because the DDT does not leave the bird's body, and because DDT resists breaking down (either in the environment or the body), it accumulates to higher levels in the bird's tissues. In other words, the DDT that was spread out over, say 1,000 crickets will be concentrated in one bird.