Ethiopia Grade 12 Biology: Unit 2 Ecology Question Answers

Decomposers (bacteria and fungi) are key in returning nutrients to the ecosystem. Important mineral elements such as nitrogen and phosphorus are returned to plants as a result of the action of decomposers

saprobiotic nutrition used by organisms such as fungi to obtain nutrients from nonliving organic matter using extracellular digestion

The various stages in a succession are called seres.

Photosynthesis removes carbon dioxide naturally — and trees are especially good at storing carbon removed from the atmosphere by photosynthesis.

climax community the most complex community that can exist under the prevailing environmental conditions

Decomposers release many mineral elements, nitrogen, phosphorus and others from organic compounds in dead bodies. These are then absorbed from the soil by plants

Saprobionts are organisms that digest their food externally and then absorb the products.

Legumes — a class of vegetables that includes beans, peas and lentils — are among the most versatile and nutritious foods available.

Decomposers form the largest population in food chain. They include microbes such as bacteria and fungi, that derive their nutrition by disintegrating the remains of animals and dead plants.

Decomposers are organisms that break down dead or decaying organisms; they carry out decomposition, a process possible by only certain kingdoms, such as fungi.

Denitrifying bacteria are microorganisms whose action results in the conversion of nitrates in the soil to free atmospheric nitrogen. Some examples of denitrifying bacteria are Thiobacillus denitrificans, Micrococcus denitrificans, and some species of Serratia, Pseudomonas, and Achromobacter.

Ammonification is the primary process that converts reduced organic nitrogen (R–NH2) to reduced inorganic nitrogen (NH4+) through the action of microorganisms.

Abiotic describes the non-living (physical) part of an ecosystem

Acid rain is caused by a chemical reaction that begins when compounds like sulfur dioxide and nitrogen oxides are released into the air.

factors that could influence the type of climax community formed include:
• temperature
• precipitation (rainfall)
• soil type
• soil depth

fossilisation – sometimes living things do not decay fully when they die due to the conditions in the soil, and fossil fuels (for example, coal, oil and peat) are formed

there is a seed bank of many of the climax plant types available in remaining undamaged plants