Do Now

1. Define trophic level.

2. What are producers? Give an example.

3. What is a heterotrophic organism? Give an example.

4. What is pyramid of numbers?

5. Explain the difference between a pyramid of biomass and productivity. (Hint: think of the grocery store analogy)

6. Why are aquatic biomass pyramids typically inverted?

7. Why do you think food chains seldom have more than four trophic levels? (Why are the number of tertiary consumers relatively low in an ecosystem?)

Practice

• Complete the To Do activity on page 74 using graph paper

• Answer To Do questions (#1-3) on page 76

• On a piece of computer paper, construct three food chains (4 trophic levels), a food web, a pyramid of numbers, a pyramid of biomass, and a pyramid of productivity for one of the following ecosystems. You may need to research some information.

Warm-water ocean Temperate Forest Mountain

Arctic ocean JunglePrairie

Pond RiverDesert

Lake TundraSavannah

Practice Continued

Label the food chains and food web with the following:

Producer(s) = P

Primary consumer(s) = 1

Secondary consumer(s) = 2

Tertiary consumer(s) = 3

Herbivores = H

Carnivores = C

Omnivores = O

On your productivity pyramid, label the amount of energy available to each organism based on their trophic level

Need to research average total energy for the main producer in your ecosystem (For example: the total energy in a grassland producer was found to be 400 kJm-2 y-1)

Do Now

Study Ecosystem Structure. You have a quiz

today!

Abiotic Stations

Rotate through 5 stations as intro to abiotic factors

Station 1: Simulation on Temperature

Station 2 & Station 3: Reading Articles

Station 4 & Station 5: Watching Videos 10 min at each station. You will be directed

when to rotate. Use your time wisely. You must answer all

questions. You will be tested on this information.

2.2 Measuring Abiotic Components

OBJECTIVE 2.2

•Marine system – the sea, salt marshes, mangrove swamps and saline estuaries•Fresh water lakes and rivers•Terrestrial systems – land based

Three main types of ecosystem:

Marine System

Key Factors:•Salinity•Temperature•pH•Dissolved oxygen content (mg/L)•Wave Action

Temperature: Marine

Temperature probes (water, soil, air)

Determines the amount of oxygen which will dissolve in sea water which will become available to marine organisms

Affects metabolic rate

Surface waters warmer than deeper water which affects ocean currents

Dissolved Oxygen: Marine

Dissolved oxygen needed for respiration

O2 + C6H12O6 CO2 + H2O + ATP

Warmer water = less dissolved oxygen

Measured by using electrodes

Wave Action: Marine

Measured using a dynamometer which asses the force in waves

Wave action increases the amount of dissolved oxygen by mixing air with water

Coastal areas and coral reefs have high levels of dissolved oxygen

Fresh-Water Ecosystem

Key Factors:

•Turbidity •pH•Flow velocity•Temperature•Dissolved oxygen

Turbidity: Freshwater

Measure of cloudiness of water

Cloudy = high turbidity

Clear = low turbidity

Secchi disc is used to measure turbidity: lowered into the water until disappears from view

Depth reading is taken from the pole

Repeated for accuracy

Always be taken in the same light

Turbidity affects sunlight penetration which influences rate of photosynthesis

https://www.youtube.com/watch?v=yGJ5uV4jAPo

Flow Velocity: Freshwater

Observe surface water

Measure by taking the time for any floating object to pass a fixed distance between two marked points

Varies at different depths

More accurate using a flow-meter which is a calibrated propeller attached to a rod

Velocity determines which organisms can survive in flowing water

High velocity = plants and animals firmly anchored

Temperature/Dissolved Oxygen: Freshwater

Temperature affects the amount of dissolved oxygen in a lake or stream and the amount of oxygen which can remain dissolved

Warm water speeds up plant growth but increases the rate of decomposition reduces the water’s ability to hold oxygen

Minimum of 5 gm-3 oxygen is needed to support a balanced aquatic community

Water agitation (waterfalls) increases dissolved oxygen

pH: Marine and Freshwater

pH meter or probe

Cleaned between readings

Used at same depth.

Soil uses soil test kit – indicator added and compared to chart.

Terrestrial Ecosystems

Key Factors:

•Temperature•Light Intensity•Soil moisture content•Wind speed•Soil particle size•Soil mineral content•Slope•Drainage

Light Intensity: Terrestrial

Measured with a light meter

Intensity varies throughout the day

Dependent on cloud cover and season

Soil Moisture Content: Terrestrial

Measure by weighing soil samples before and after drying

Soil contains moisture and organic matter

Soil samples are heated to remove water

Samples weighed at intervals until a constant dry weight is reached

Wind Speed: Terrestrial

Measured with a digital anemometer

Cups on device revolve = rotations per unit time

Soil Particle Size: Terrestrial

Determines how much water soil can hold and how quickly the soil will drain

Passed through series of graduated sieves with different mesh sizes

Silt and clay are smaller

Soil Mineral Content: Terrestrial

Ratio of mineral to organic material present Organic content: plant and animal

residues in various stages of decay

Determines the soil’s ability hold water and its fertility

Measured by the loss-on-ignition (LOI) method Weighed soil samples are heated

organic matter is burnt off

Loss in mass is calculated once the sample has reached constant mass and no further change

Percentage weight lost gives a crude measure of the organic content of the soil

Slope: Terrestrial

Influences water runoff

Determines whether erosion is likely to be a problem

Drainage: Terrestrial

Too much or too littler water in soil can reduce plant growth

Drainage affected by soil type, humus content, and slope

Poor drainage = soil becomes water logged plants are unable to take up nutrients

Toxic compounds build up due to lack of oxygen (anaerobic conditions)

Slower to warm up in spring and summer inhibits germination and growth of seeds