Week 6: Succession, Climate, Biomes, and Ecosystems (copy)

Succession

The orderly replacement of populations of plants and animals in an area following a disturbance, until a stable community is established.

Climax Community

The stable community at the end of succession, determined by local climate, which has the largest population and species diversity.

r-selected species

Species that produce many offspring with less investment in each.

K-selected species

Species that produce fewer offspring but invest more resources in their care.

Causes of Succession

Succession is largely driven by the organisms themselves, modifying their environment to make it less favorable for current species and more suitable for others.

Primary Succession

Occurs in an area with no soil, progressing from autotrophic prokaryotes to trees.

Secondary Succession

Begins in an area where soil remains after a disturbance, like after a forest fire.

Pioneers

Species like lichens that are vital in early stages on new rock and soil surfaces.

Indicator Species

Species that can signal environmental changes, such as lichens indicating air quality issues.

Example of Succession in Alaska

After glacial retreat, pioneer species like alder are succeeded by Sitka spruce and mountain hemlock.

Climate

Long-term prevailing weather conditions in a region that influence the distribution of organisms.

Determinants of Climate

Major abiotic components affecting climate include temperature, precipitation, sunlight, and wind.

Equatorial Climate

Warm temperatures and high precipitation are found at the equator.

Desert Formation

Deserts form at the Tropics of Cancer and Capricorn due to subsiding dry air.

Biomes

Major types of ecosystems occupying broad geographic areas, characterized primarily by vegetation type and climate.

Grassland Biome

A biome dominated by grasses.

Temperate Deciduous Forest

A biome dominated by deciduous trees.

Aquatic Biomes

Biomes classified by physical and chemical characteristics, not by dominant vegetation.

Oligotrophic Lakes

Nutrient-poor, oxygen-rich, deep, cold lakes with low productivity.

Eutrophic Lakes

Nutrient-rich, oxygen-poor, shallow, warm lakes with high productivity.

Gross Primary Productivity (GPP)

The total primary production in an ecosystem.

Net Primary Productivity (NPP)

GPP minus the energy used for respiration by primary producers.

Limiting Nutrients

Essential elements required for production that are found in short supply; nitrogen and phosphorus are common limiting nutrients.

Eutrophication

A process where excessive nutrients lead to algal blooms, causing ecological impacts.

Water Cycle

The movement of water through evaporation, transpiration, condensation, precipitation, and groundwater.

Carbon Cycle

The cycle involving processes like photosynthesis and respiration, where CO2 is released from natural and human sources.

Nitrogen Cycle

The cycle where nitrogen is converted by bacteria into forms available to plants.

Phosphorus Cycle

Involves phosphate as the primary inorganic form, with major reservoirs in marine sedimentary rocks.

Human Impact on Nutrient Cycling

Human activities disrupt ecosystems, affecting trophic structures and nutrient cycles.

Greenhouse Effect

A phenomenon where rising CO2 levels due to human activities contribute to climate change.

Climate Change Implications

Include rising global temperatures and changing species distributions.