• Intertidal zones – area of ocean shores where tides produce a rhythmic rise and fall of water (animals are adapted to periodic exposure to air, to the force of waves crashing onto the shore).

• Estuaries – is a biome where freshwater rivers and streams flow into the sea (great variation in temperature and salinity, exposure to the air during low tide).

Freshwater Biome:

Low levels of dissolved salts characterise the Freshwater Biome (0.005% salt content)

• Lakes and Ponds

• Eutrophic lakes are rich in organic matter and vegetation, making the waters relatively murky.

• Oligotrophic lakes contain little organic matter.

• River and Streams

A river is a body of water that flows down a gradient, or slope, towards its mouth.

The limiting abiotic factor in a river is a gradient or current.

Summary:

• The interaction of biotic factors and abiotic factors results in the great diversity of ecosystems in the biosphere.

• Formation of different biogeographical zones and major biomes due to two reasons: geology history and climate.

• Plants and animals become adapted to life in particular biomes through a process of evolution by natural selection (Mechanism of evolution was determined by Charles Darwin).

• Adaptations – are traits that give an organism an advantage in an environment.

Variations of adaptations are essential for continuity of life, because they have an advantage on some members of

a species in a changeable environment.

• The earth’s biomes are primarily controlled by temperature and precipitations

Key terms:

Abiotic factors Biotic factors Anthropogenic factors Critical limiting factor Range of tolerance Tolerance limits Homeostasis Adaptation

Competition: - Intraspecific - Interspecific Predation Parasitism Symbiosis: - Mutualism - Commensalism

Ecological groups: Eyrobionts. Stenobionts Xerophytes Homeothermics Poikilotehermics Terrestrial Biomes Aquatic Biomes

Liebig’s law of the minimum Shelford’s principle of tolerance limits Darwin’s mechanism of evolution by natural selection

Questions for review (orally):

1. Present classification of ecological factors. Give examples of factors interactions.

2. Compare different types of biotic relationships. Give examples

3. Explain the Liebig’s law of the minimum.

4. Explain the Shelford’s principle of tolerance limits.

5. Name some ecological groups. Give examples.

6. Name the major terrestrial biomes. What are limiting factors for each biome?

7. Name the main aquatic biomes. Define the critical factors for each biome

Make a synopsis: Daniel D. Chiras, “Environmental Science: Creating Sustainable Future”

1. Draw a graph of range of tolerance (p.65, fig. 5-4).

Critical Thinking (orally):

1. Deciduous forests once covered large portions of North America and Europe. However, humans have cleared much of these forests to make way for cities and towns. How do you think this shrinking area has affected plants and animals in the remaining forests?

2. Although plants of the coniferous forest and desert biomes seem to have little in common, both contend with dry conditions and brief growing seasons. Compare the ways in which conifers and succulent plants are adapted to these conditions.

3. Estuaries serve as breeding sites for thousand of species of marine animals. What characteristics of this biome would make estuaries advantageous areas for fishes, molluscs, and other aquatic animals to reproduce? What might be disadvantages of reproducing in estuarine areas?

4. Humans are a major competitive force in nature. Prove it.

5. Describe ways in which humans alter conditions within their own range of tolerance.