Population and Environmental Management: Key Concepts in Ecology and Agriculture

Age Structure Diagram

A graph showing the distribution of a population by age and sex, used to predict future population growth.

Aquaculture

The cultivation of aquatic organisms such as fish, shellfish, or algae for food.

Baby Boom

A period of unusually high birth rates that increases population size rapidly.

Biological Control

Using natural predators, parasites, or pathogens to control pest populations.

Birth Rate (CBR)

The number of live births per 1,000 people per year.

Broadspectrum Pesticide

A pesticide that kills a wide variety of organisms, including non-target species.

Brownfield

Abandoned or underused industrial land that may be contaminated and requires cleanup.

CAFOs (Concentrated Animal Feeding Operations)

Large-scale livestock facilities where animals are confined and fed, producing large amounts of waste.

Carrying Capacity

The maximum population an environment can support indefinitely without degradation.

Cash Crop

A crop grown primarily for sale and profit rather than personal consumption.

CDR (Crude Death Rate)

Number of deaths per 1,000 people per year.

City Planning

The organization and design of cities to manage growth, transportation, and resources.

Clear-Cutting

A forestry practice where all trees in an area are removed at once.

Composting

The breakdown of organic waste into nutrient-rich fertilizer.

Contour Farming

Farming along the natural contours of land to reduce soil erosion.

Controlled Burning

The intentional use of fire to manage ecosystems and reduce wildfire risk.

Deforestation

The removal of forests faster than they can regrow.

Demographic Transition Model

A model that shows changes in birth and death rates as a country develops.

Demography

The study of population size, structure, and distribution.

Density Dependent Factors

Limiting factors that increase in effect as population density rises (disease, competition).

Density Independent Factors

Limiting factors that affect populations regardless of size (natural disasters, climate).

Desertification

The process by which fertile land becomes desert due to overuse or climate change.

Doubling Time

The time required for a population to double in size.

Emigration

The movement of individuals out of a population.

Even-Aged Stands

Forests in which most trees are the same age.

Exponential Growth

Rapid population growth under ideal conditions, producing a J-shaped curve.

Family Planning

Efforts to control population growth through education and contraception.

Fallow

Agricultural land left unplanted to restore soil nutrients.

Feedlot Runoff

Pollution caused by animal waste washing from feedlots into waterways.

Fisheries

The management and harvesting of fish populations for human use.

Genetic Engineering

The direct modification of an organism's DNA.

GMO (Genetically Modified Organism)

An organism whose genetic material has been altered through biotechnology.

Green Belt

Protected open land around cities designed to limit urban sprawl.

Green Revolution

Increased agricultural production due to high-yield crops, fertilizers, irrigation, and pesticides.

Ground Subsistence

Farming practiced mainly to feed the farmer and local community.

Growth Rate

The rate at which a population increases or decreases.

Herbicide

A chemical used to kill unwanted plants or weeds.

Hydroponic

Growing plants without soil using nutrient-rich water solutions.

Immigration

The movement of individuals into a population.

Impervious Surface

Surfaces that prevent water from soaking into the ground, increasing runoff.

Industrialized Agriculture

Large-scale, mechanized farming dependent on chemical inputs.

Infant Mortality Rate

The number of deaths of infants under one year old per 1,000 live births.

Inorganic Fertilizer

Fertilizer made from synthetic chemicals or mined minerals.

Insecticide

A pesticide designed to kill insects.

IPAT Model

A formula estimating environmental impact: Impact = Population × Affluence × Technology.

IPM (Integrated Pest Management)

Pest control strategy combining biological, mechanical, and limited chemical methods.

Microclimate

Climate conditions in a small, localized area.

Migration

The movement of people from one region to another.

Monoculture

The cultivation of a single crop species over a large area.

MSY (Maximum Sustainable Yield - Crop Production)

The largest harvest that can be maintained without reducing future yields.

Multiple Use Land

Land managed for multiple purposes such as recreation, logging, and grazing.

Narrow Spectrum Pesticide

A pesticide that targets specific pest species.

Natural Pesticide

Pest control substances derived from natural sources.

Nitrates

Nitrogen compounds that act as fertilizers but can cause water pollution and eutrophication.

No-Till Agriculture

Farming method that avoids plowing to reduce erosion and improve soil health.

Old Growth Forests

Forests that have not been significantly disturbed by human activity.

Organic Fertilizer

Fertilizer made from plant or animal waste.

Overgrazing

Excessive grazing that damages vegetation and leads to soil erosion.

Pest

Any organism that competes with humans for resources or spreads disease.

Pesticide

A chemical used to kill pests.

Pesticide Treadmill

A cycle in which pests develop resistance, requiring increased pesticide use.

Public Lands

Land owned and managed by the government for public use.

Replacement Level Fertility

The number of children per woman needed to maintain population size (about 2.1).

Rodenticide

A pesticide designed to kill rodents.

Ruminant

Hoofed mammals with multi-chambered stomachs that digest plant material (e.g., cows).

Second Growth Forest

A forest that regrows after being logged or disturbed.

Seed Bank

A storage facility that preserves seeds for future planting or biodiversity protection.

Seed Tree Cutting

A logging method that leaves select trees to reseed the forest.

Selective Cutting

Removing specific trees while leaving the rest of the forest intact.

Shelterbelts

Rows of trees planted to reduce wind erosion and protect crops.

Shelterwood Cutting

Gradual removal of trees to allow new growth under shelter.

Slash-and-Burn Agriculture

Clearing land by cutting and burning vegetation.

Survivorship Curves

Graphs showing survival rates of organisms at different ages.

Synergy

When combined substances have a greater effect together than individually.

The Rule of 70

A method to estimate population doubling time (70 ÷ growth rate).

TFR (Total Fertility Rate)

The average number of children a woman is expected to have.

Traditional Subsistence Agriculture

Small-scale farming using human or animal labor to meet local needs.

Type I Survivorship Curve

High survival until old age (humans).

Type II Survivorship Curve

Constant mortality rate throughout life.

Type III Survivorship Curve

High mortality early in life (fish, plants).

Uneven-Aged Stands

Forests with trees of many different ages.

Urban Forestry

The management of trees and green spaces in urban areas.

Urban Sprawl

The expansion of low-density development into rural land.

Urbanization

The movement of people from rural areas into cities.