Ecology Notes

Ecosystem

A community of interacting organisms (biotic factors) and their physical environment (abiotic factors).

Biotic Factors

Living parts of an ecosystem, such as plants, animals, and microorganisms.

Abiotic Factors

Non-living parts, including sunlight, temperature, water, pH, salinity, and soil.

Producers (Autotrophs)

Organisms like plants that convert solar energy into chemical energy through photosynthesis.

Consumers (Heterotrophs)

Organisms that obtain energy by consuming other organisms, including herbivores, carnivores, omnivores, and decomposers.

Food Chains and Food Webs

Models that depict the flow of energy through an ecosystem.

Trophic Levels

Levels in an ecosystem, made of producers at the bottom and consumers at higher levels.

Energy Loss at Trophic Levels

At each trophic level, 90% of energy is lost as heat due to metabolic processes.

Nutrient Cycling

Nutrients cycle within ecosystems, involving key cycles like the Carbon Cycle, Nitrogen Cycle, and Water Cycle.

Carbon Cycle

Involves processes like photosynthesis, respiration, decomposition, and combustion.

Water Cycle

Comprises evaporation, condensation, precipitation, infiltration(when liquid substance passes into or through a material or organization, through filtering or seeping), and transpiration(plants absorb water through their roots and then give off water vapor from their leaves).

Carrying Capacity

The maximum population size of a species that an environment can sustain indefinitely.

What is the lag phase in population growth?

Slow initial growth.

What characterizes the exponential phase in population growth?

Rapid increase.

What happens during the steady state phase of population growth?

Population stabilizes.

What leads to the decline/extinction phase in population growth?

Resource depletion or other factors.

Limiting Factors

Environmental factors that restrict population growth, such as food availability, predation, disease, and habitat space.

Exponential Growth

Characterized by a J-shaped curve, where the population grows rapidly without limits.

Logistic Growth

Depicted by an S-shaped curve, where population growth slows as it approaches carrying capacity due to limiting factors.

Dynamic Equilibrium

Ecosystems are dynamic, constantly changing with inputs and outputs of energy and matter. A healthy ecosystem maintains dynamic equilibrium—a balance between inflow and outflow. Disruptions are things like pollution and invasive species that can throw the system out of balance.

A Community

Includes all populations in an area interacting with each other. Interdependence - a relationship where 2 or more organisms depend on each other.

Symbiosis:

Mutualism - A relationship where both organisms benefit

Commensalism - A relationship where one organism benefits and the other is unaffected.

Parasitism - A relationship where one organism benefits and the other is harmed.

Primary Succession

The development of ecosystems in areas where no life previously existed, beginning with pioneer species.

Secondary Succession

The re-establishment of ecosystems in areas where they previously existed but were disturbed.

Natural Events

Events like hurricanes, wildfires, and droughts that can alter ecosystems by changing habitats and resource availability.

Human Activities

Urban development, pollution, deforestation, and introduction of invasive species that can impact ecosystems.

Pollution

Introduction of harmful substances into the environment.

Habitat Destruction

Loss of natural habitats due to urbanization, deforestation, etc.

Climate Change

Long-term alterations in temperature and weather patterns, often attributed to human activities.

Virginia Ecosystems

Diverse ecosystems in Virginia, including forests, wetlands, coastal regions, freshwater, and mountains.

Forests

Ecosystems dominated by deciduous and coniferous trees, home to species like white-tailed deer and various bird species.

Wetlands

Areas saturated with water, supporting unique plant and animal life, including marshes and swamps.

Coastal Regions

Ecosystems influenced by proximity to the Atlantic Ocean, including estuaries and beaches.

Freshwater

Rivers with various fish species and aquatic plants.

Mountains

Elevated regions with distinct flora and fauna.

Nitrogen Cycle

Includes nitrogen fixation, nitrification, assimilation, ammonification, and denitrification.

Fixation

Converts nitrogen in the air to ammonium, biologically available

Nitrification

Bacteria change ammonium to nitrates to be absorbed by plants

Assimilation

Plants absorb nitrates by the roots

Ammonification

Decomposers change nitrogen into ammonium to re-enter the cycle

Denitrification

Nitrogen in the soil gets back into the air