Ecology IB Bio SL

Identify the trophic level for each organism in the food web below

Producers: carrots, grasses, grains

Primary consumers: rabbit, mice, grasshopper, bird

Secondary consumers: fox, owl, bird

Tertiary consumer: fox

What impact does the increase of carbon dioxide in the atmosphere have on the ocean?

The ocean absorbs carbon dioxide which makes the ocean more acidic. This causes coral to deposit less calcium in their bodies causing coral bleaching

Describe peat

• Partially decomposed plant material

• Can be used as a fossil fuel

• Waterlogged soil

How does climate change impact natural selection?

• Some organisms are adapted for variation in climate and changes in the climate

• Organisms that are able to adapt to changes in food chains will survive better → reproduce and pass on their genes

• Organisms not adapted to climate changes will die/disappear over time

• Changes in a species may occur or new species may appear

Distinguish between saprotrophs and detritivores.

• Saprotrophs: digest organic matter then absorb it and live on/in organic matter

• Detritivores: eat (ingest) dead leaves, feces, and carcasses (organic matter)

Why don’t food chains contain more than four or five trophic levels?

• 90% of energy is not transferred to the next trophic level

• Energy is lost through respiration, heat loss, waste (feces and urine)

How did pollution impact the light and dark moths and their ability to camouflage?

Pollution made the bark of trees darker so the light colored moths were no longer able to blend in with the bark so their population decreased.

Describe how energy flows through an ecosystem.

• Energy from the sun captured by plants and other autotrophs Sunlight energy converted in photosynthesis

• Energy is passed to animals or other consumers

• Energy is lost at each trophic level

• Only about 10% of the energy is passed to the next trophic level

• Some energy is left for decomposers

Draw an example of a food chain.

Grass → Grasshopper → Frog → Snake → Eagle

What impact does methane have on climate change?

Methane is a greenhouse gas (GHG) that causes an increase in temperature in the atmosphere; most powerful GHG but has a much shorter lifespan than CO2

What is the role of bacteria in the carbon cycle?

• Decomposes dead material causing formation of CO2 from respiration

• Saprotrophic bacteria partially decomposes dead material in waterlogged soil resulting in peat formation

• Photosynthetic bacteria fixes CO2 during photosynthesis

Describe carbon sinks

Reservoirs that absorb and store CO2 from the atmosphere. In the ocean, photosynthesis will increase the size of the carbon sink

Define community, population, and ecosystem

• Population: group of the same species

• Community: multiple populations interacting with each other

• Ecosystem: community plus the abiotic factors