Ecology & Soil Science Lecture Review

Flashcards covering key vocabulary from the lecture notes on Ecology and Soil Science, including concepts like productivity, ecosystem structure, soil components, population dynamics, biodiversity, and limiting factors.

Ecology

The study of ways organisms interact with each other and with their nonliving surroundings.

Emergent Behavior

Properties or behavior of a system that is surprising and unintended by any member of the system.

Gross Primary Productivity (GPP)

The total rate of photosynthesis or the energy assimilated by producers.

Net Primary Productivity (NPP)

The amount of energy that remains after accounting for energy used by producers (NPP = GPP - Energy used in respiration).

Unintended Consequences

Outcomes that are not foreseen or deliberately planned, such as channelizing rivers increasing erosion and flooding.

Abiotic Factors

Nonliving components of an ecosystem structure, including energy, matter, temperature, light, water, nutrients, soil, pH, and minerals.

Biotic Factors

The biological environment within an ecosystem structure.

Limiting Factors

Constraints on growth in a system, often due to the scarcest resource rather than the total available.

Environment

Everything that affects an organism together during its lifetime.

Ecosystem

The community of living organisms together with nonliving components of their environment interacting as a system.

Soil

The unconsolidated mineral and organic material on the immediate surface of the Earth that serves as a natural medium for the growth of land plants.

Components of Soil

Mineral matter, water, air, and organic matter (half solid matter and half pore space).

5 Factors of Soil Formation

Parent material, organisms, climate, topography, and time.

Parent Material (Soil)

The weathered bedrock that initiates soil formation.

Mycorrhizae

A mutualistic association between fungi and plant roots.

Soil Texture

Refers to the mineral matter from parent material (stable particles) and organic matter (variable size).

Soil Porosity

The ability of water and air to move through the soil profile, depending on particle size and distribution.

Bulk Density

The mass of soil and associated pore space in the absence of soil water in a specified volume.

Humus

The organic matter fraction of soil formed by the decomposition of living plant matter.

Soil Organic Matter (SOM)

Improves moisture and nutrient holding capacity of soils, lowers leaching losses, and is influenced by soil management.

Adsorption

The process where positive ions associate with the negative ions on the surface of clays and soil organic matter.

Cation Exchange Capacity (CEC)

The quantity of negative sites available in soil where nutrients are directly exchanged, balancing charges.

Soil Horizons

Layers of soil (O, A, E, B, C, R) that develop from parent material through time in contact with climatic and organism variables.

Universal Soil Loss Equation (USLE)

An equation (A = R x K x LS x C x P) used to estimate average annual soil loss from a given area.

Tolerable Soil Loss

The maximum amount of soil loss in tons per acre per year that can be tolerated while permitting high crop productivity.

Evolutionary Process

Includes genetic flow, genetic drift, mutation, and natural selection.

Resilience

The ability to bounce back after being disturbed; also known as elasticity.

Light Reaction

The process in photosynthesis that converts light energy into chemical energy.

Fundamental Niche

An n-dimensional hypervolume of environmental conditions and resources which allow an organism to survive and reproduce.

Realized Niche

The niche an organism occupies due to interactions with competitors and predators.

Ectothermic

Organisms that rely on external heat sources such as sunlight to achieve a normal body temperature.

Endothermic

Organisms that can generate and maintain a stable internal body temperature through metabolic processes.

Liebig’s Law of the Minimum

The principle that growth is controlled not by the total of resources available, but by the scarcest resource.

Intrinsic Limiting Factors

Factors that originate from within the population itself.

Extrinsic Limiting Factors

Factors that originate from outside the population.

Density-Dependent Limiting Factors

Factors like predation, competition, waste accumulation, and diseases that increase with higher population density.

Density-Independent Limiting Factors

Factors like weather, natural disasters, and pollution that are not related to population density.

Carrying Capacity

The maximum sustainable population for an environment.

Lag Phase (Population Growth)

The first portion of a population growth curve characterized by slow population growth.

Exponential Growth Phase

A period in population growth where more organisms reproduce, causing accelerated growth, continuing as long as the birth rate exceeds the death rate.

Deceleration Phase

A stage in population growth where the growth rate slows as the death rate and birth rate become similar.

Stable Equilibrium Phase

A stage in population growth where the death rate and birth rate become equal, and the population stops growing.

Biodiversity

The variety of living things.

Genetic Biodiversity

The variety of different versions of the same genes within a species.

Species Biodiversity

The number of different kinds of organisms within an ecosystem.

Ecosystem Biodiversity

The number of different ecosystems in a given area.

Habitat Loss and Fragmentation

A major cause of past extinctions where the ability to migrate between fragmented patches is reduced.

Novel Entities

Areas that have been significantly altered by human activity.

Biogeochemical Flows

The cycling of chemical elements, such as Nitrogen (N) and Phosphorus (P), through ecosystems.