Ecosystems and Communities Flashcards

Flashcards based on the lecture notes about ecosystems and communities.

What is succession?

Communities proceed through recognizable, predictable changes in structure over time.

What is a climax community?

A relatively stable, long-lasting community that is the result of succession.

What factors affect the climax community?

Climate, soil characteristics, water availability, and disturbance frequency.

What are some characteristics of climax communities?

Maintain mix of species for a long time; Specialized niches; Recycle nutrients.

What is an organism's habitat?

The space that an organism inhabits.

What is an organism's niche?

The functional role an organism has in its surroundings.

What is an example of a substrate that influences succession?

Rock, sand, or clay.

What is primary succession?

A successional progression that begins with a total lack of organisms and bare mineral surfaces or waters.

What is secondary succession?

A successional progression that begins with the destruction or disturbance of an existing ecosystem.

What are the key differences of primary succession?

No soil present; begins with no life.

What are the key differences of secondary succession?

Soil already present; follows removal of existing biota.

Where does terrestrial primary succession occur?

Rock and sand.

Where does aquatic primary succession occur?

Standing water.

What are the soil conditions during the pioneer stages of terrestrial primary succession?

No soil, little moisture, and few nutrients.

What type of flora can be seen during the intermediate stages of terrestrial primary succession?

Annual plants, small perennial grasses, and herbs.

What is a sere?

The entire sequence of stages from pioneer community to climax community.

What is present during the pioneer stages of terrestrial primary succession?

Windblown spores or tiny reproductive units.

What happens to most aquatic ecosystems?

They will disappear and replaced by terrestrial ecosystems as a result of normal successional processes.

What do aquatic ecosystems receive a continuous input of?

Soil particles and organic matter from surrounding land.

What occurs during the later stages of aquatic primary succession?

Sediment accumulation leading to shallower water.

What occurs during secondary succession?

Existing communities destroyed, soil and some organisms remain.

What are biomes?

Ecosystems with wide geographic distribution.

What are the types of zonal vegetation?

Latitude and longitudal placement.

What are biomes determined by?

Climate.

What are some examples of biomes in Eastern Europe, West Siberia, Central Asia, and Arabia?

Tundra, tiaga forest, temperate grassland, temperate desert, and subtropical desert.

What aspects of precipitation are important in biome determination?

Total amount, form, and seasonal distribution.

What are the climate conditions in a desert?

Less than 25 cm annual precipitation; windy; large daily temperature fluctuations.

What is a specialty of desert ogranisms?

Ability to conserve water.

What are climate conditions in a temperate grassland?

25-75 cm annual precipitation, fire is important.

What is the human impact on temperate grassland?

Converted to agriculture or raising domesticated grazers.

What is the human impact on savannas?

Farming and livestock.

What is the amount of annual pecipitation in the Savanna?

50-150 cm annual precipitation, unevenly distributed.

What seasonal climate does Mediterranean Shrublands boast?

Wet, cool winters and hot, dry summers.

Where do most tropical dry forests occur?

Occur in areas of very high human population.

What is a major climate influence on Tropical Dry forests?

Highly influenced by seasonal rainfall.

What is the human impact on Tropical Rain forests?

Logging and agriculture.

What is the climate like in a tropical rainforest?

Warm and constant temperatures; high annual rainfall (≥ 200 cm).

What are the characteristics of the tropical rainforests?

They have a multi-layered canopy and a very high diversity of species.

What are the climate conditions in a temperate deciduous forest?

75-100 cm annual precipitation, evenly distributed; mild winters and long growing season.

Much of the current forests are subjected to what?

logging.

What are specific tree species found in a Temperate Deciduous Forest?

Maples, birch, and oaks.

What are the climate conditions in a temperate rain forest?

At least 130 cm of rain a year; cool climate slows evaporation.

What are the adaptations of Northern Coniferous Forest Trees?

Needle-shaped leaves and flexible branches.

What are the dominant trees found in the temperate rainforest?

Douglas fir and Sitka spruce.

What are the conditions in Northern Coniferous Forest or Boreal Forest?

An evergreen coniferous forest with short, cool summers and long winters with abundant snowfall.

What is a Tundra?

Has a permanently frozen subsurface soil

What is the human impact on the Tundra?

Damage is slow to heal.

How can aquatic ecosystems be divided?

Marine (saltwater) and freshwater ecosystems.

What factors determine aquatic ecosystems?

Ability of sun’s rays to penetrate water; water depth; nature of bottom substrate; water temperature; dissolved salts.

What organisms make up a pelagic marine ecosystem?

Plankton.