ecosystems and communities 4.3 – 4.5 biology. what is ecological succession? ecological...

ECOSYSTEMS AND COMMUNITIES

4.3 – 4.5Biology

WHAT IS ECOLOGICAL SUCCESSION?

Ecological succession is a series of more-or-less predictable changes that occur in a community over time.

Ecosystems change over time, especially after disturbances, as some species die out new species move in.

WHAT IS THE DIFFERENCE BETWEEN PRIMARY AND SECONDARY SUCCESSION?

Primary succession begins in an area with no remnants of an older community. The first species that colonizes barren areas are known as pioneer species.

WHAT IS THE DIFFERENCE BETWEEN PRIMARY AND SECONDARY SUCCESSION?

Secondary succession occurs in disturbed areas where remnants of previous ecosystems – soil and even plants – remain.

WHAT IS A CLIMAX COMMUNITY?

Undisturbed succession progresses to a point where it produces a specific and stable community. An example would be “the magical forest”.

CAN ALL ECOSYSTEMS RECOVER FROM EXTENSIVE HUMAN-CAUSED DISTURBANCES?

Clearing and farming of tropical rainforests can change the microclimate and soil enough to prevent regrowth of the original community.

WHAT ARE BIOMES AND HOW ARE THEY DESCRIBED?

Biomes are regional climate communities. They are described in terms of abiotic factors like climate and soil type, and biotic factors like plant and animal life

The ten major biomes are tropical rain forests, tropical dry forests, tropical grasslands, desert, temperate grassland, temperate woodland/shrubland, temperate forest, northwestern coniferous forest, boreal forest, and tundra.

WHAT ARE BIOMES AND HOW ARE THEY DESCRIBED?

You are responsible for knowing each type of biome, its abiotic factors, and biotic factors. (Pg. 112)

WHAT ARE AQUATIC ECOSYSTEMS AFFECTED BY?

Aquatic ecosystems are affected primarily by the water’s depth, temperature, flow, and amount of dissolved nutrients.

WHAT TERMS ARE USED TO DESCRIBE WATER DEPTH?

The photic zone is the sunlit region near the surface that allows photosynthesis to occur.

WHAT TERMS ARE USED TO DESCRIBE WATER DEPTH?

The aphotic zone is below the photic zone. This is an area so deep that light cannot reach it. Photosynthesis cannot occur here.

WHAT TERMS ARE USED TO DESCRIBE WATER DEPTH?

Benthos are aquatic organisms that live on, or in, rocks and sediments on the bottoms of lakes, streams, and oceans. The benthic zone, in shallow water, can be home to algae and other aquatic plants. When the benthic zone is too deep, below the photic zone, chemosynthetic autotrophs are the only primary producers.

WHAT ARE THE THREE MAJOR CATEGORIES OF FRESHWATER ECOSYSTEMS?

Rivers and streams Lakes and ponds Fresh water wetlands

WHAT ARE THE THREE MAJOR CATEGORIES OF FRESHWATER ECOSYSTEMS?

A wetland is an ecosystem in which water either covers the soil or is present at or near the surface for at least part of the year.

WHAT IS AN ESTUARY AND WHY IS IT SO IMPORTANT?

An estuary is a special kind of wetland formed where the river meets the sea.

Estuaries contain a mixture of fresh water and salt water and are affected by the rise and fall of ocean tides. They support an astonishing amount of biomass which makes them commercially valuable. They serve as spawning grounds for many ecologically and commercially imported fish and shell fish species.

HOW DO ECOLOGISTS CLASSIFY MARINE ECOSYSTEMS?

Ecologists typically divide the ocean into zones based on their depth and distance from shore.

Costal ocean

Open ocean