Feb Exam

Ecological succession

Ecological succession

The process by which the structure of a biological community evolves over time.

Primary succession

Occurs in lifeless areas where the soil is incapable of sustaining life, such as newly formed sand dunes or rocks left from a retreating glacier.

Secondary succession

Occurs in areas where a community previously existed and has been removed, characterized by smaller-scale disturbances that do not eliminate all life and nutrients.

Pioneer species

The first species to colonize newly created or disturbed environments during the process of succession, including lichens, mosses, and fungi.

Indicator species

A species that provides information about the health and condition of an ecosystem, often used to assess environmental conditions or changes.

Sustainable forestry

Using sustainable methods to log trees, including reusing wood and protecting forests from pests and wildfires.

Even-aged stands

Trees that grow at the same size due to clearcutting, where trees are cut down all at once.

Uneven-aged stems

Trees that grow at different sizes, promoting biodiversity and a more natural forest structure.

The Green Revolution

Industrial agriculture characterized by mechanization and standardization, leading to increased productivity but also negative impacts such as soil erosion and loss of genetic diversity.

GMOs (Genetically Modified Organisms)

Organisms that have been genetically modified to be healthier, cheaper, and more productive, but can also have negative effects such as allergic reactions and increased antibiotic resistance.

Irrigation

The process of supplying water to crops, but can lead to issues such as waterlogging and salinization.

Pest control

The use of pesticides to control or eliminate pests, with pros including increased crop yield but cons such as human health risks and harm to non-target organisms.

Biocontrol

Using living organisms or their products to control pests, reducing reliance on chemical pesticides, but with the risk of invasive species.

IPM (Integrated Pest Management)

A method that uses a variety of techniques to control pests and minimize environmental impact, including biological, physical, and chemical methods.

Sustainable soil

Practices such as contour plowing, terracing, and crop rotation to prevent soil erosion and maintain soil fertility.

Free range

A method of meat production where animals have access to the outdoors, but can lead to overgrazing and waste issues.

CAFOs (Concentrated Animal Feeding Operations)

Intensive meat production systems that raise ethical concerns, increase antibiotic use, and generate waste issues.

Aquaculture

The farming of fish and other aquatic organisms, with benefits such as cost-effectiveness but concerns about waste and genetic modification.

Overfishing

The excessive harvesting of fish that can lead to loss of biodiversity, with solutions including catch limits, treaties, and laws to protect endangered species.

Mining

The extraction of minerals from the Earth's surface or underground, with impacts such as soil erosion, water pollution, and habitat destruction.

Urbanization

The process of population growth and expansion of cities, with benefits such as compact population and disadvantages such as increased pollution and CO2 emissions.

Density-independent

Environmental factors that affect population size regardless of its density. Examples include natural disasters, weather events, and human activities.

Density-dependent

A factor that affects population growth or size based on the density of the population. Examples include competition for resources, predation, and disease.

K-Strategist

Species that have few offspring, long life spans, and invest heavily in parental care.

r-Strategist

Organisms that prioritize high reproductive rates and rapid population growth. They produce many offspring, invest little parental care, and have short lifespans.

Type 1 Survival Curve

High early survival, steep decline in later life. Common in humans and large mammals. Examples include elephants and whales.

Type 2 Survival Curve

Shows a constant mortality rate throughout an organism's lifespan. Common in large mammals, where individuals have a relatively stable chance of dying at any age.

Type 3 Survival Curve

High early mortality followed by low survivorship. Common in species with many offspring and little parental care. Examples include insects and fish.

Logistic Growth

A type of population growth that starts with exponential growth but eventually levels off due to limited resources or environmental factors, forming an S-shaped curve. It represents a balance between birth rate and death rate, leading to a stable population size.

Exponential Growth

A rapid and continuous increase in quantity over time, where the rate of growth is proportional to the current amount. It results in a J-shaped curve on a graph. Example: Population growth, compound interest.

Resource Partitioning

The process by which different species divide and share limited resources in an ecosystem to reduce competition. This allows species with similar needs to coexist by utilizing different parts of the resource or occupying different niches within the ecosystem.

O Horizon

The topmost layer of soil, composed of organic matter like decomposing leaves and plant material. It is rich in nutrients and serves as a vital layer for supporting plant growth and soil fertility.

A Horizon

The top layer of soil, also known as topsoil, characterized by its dark color and high organic matter content. It is the most fertile layer and supports plant growth.

E Horizon

The uppermost layer of soil characterized by the accumulation of organic matter, minerals, and nutrients. It is commonly referred to as the "eluviation layer" as it is where minerals and nutrients are leached out of the soil. This layer is vital for supporting plant growth and provides a habitat for microorganisms.

B Horizon

This layer is characterized by the accumulation of minerals, organic matter, and clay particles that have leached down from the layers above. This horizon plays a crucial role in the movement of water and nutrients within the soil profile.

C Horizon

This layer consists of weathered parent material; lacks organic matter and nutrients; often referred to as the "parent material horizon."

R Horizon

The deepest layer of soil, also known as the bedrock. It consists of unweathered parent material and is mostly composed of solid rock.

Stage 1 of Demographic Transition

• High birth rates and high death rates

• Population growth is slow

• Predominantly agrarian society

• Limited access to healthcare and sanitation

• High infant mortality rate

• Short life expectancy

Stage 2 of Demographic Transition

• High birth rates

• Rapid population growth

• Declining death rates

• Improved healthcare and sanitation

• Industrialization and urbanization

• Improved access to education

• Shift towards smaller family sizes

Stage 3 of Demographic Transition

• Declining birth rates

• Stable or slowly declining death rates

• Increase in urbanization and industrialization

• Improved healthcare and access to contraception

• Shift towards smaller family sizes

• Population growth slows down

• Age structure starts to shift towards an older population

Stage 4 of Demographic Transition

• Low birth rates and low death rates

• Stable population growth

• High life expectancy

• Developed countries

• Focus on education and healthcare

• Aging population

• Declining fertility rates

Total Fertility

The average number of children that would be born to a woman in her lifetime if she were to experience the current age-specific fertility rates throughout her reproductive years.

Life Expectancy

The average number of years a person is expected to live.

Birth Rate

Number of live births born per 1,000 people in a population.

Replacement Birth Rate

Number of children a couple must have to replace themselves.

Mortality Rate

Number of people that die per 1,000 people in the population.

Immigration

The process of individuals moving to a different country to establish permanent residence.

Emigration

The process of leaving one's own country to permanently settle in another country.

Final Stable Community

The stage in ecological succession where a community remains relatively unchanged in species composition and environmental conditions. It represents a balanced and self-sustaining ecosystem that can persist for an extended period without significant disturbance.

Number One Source of Soil Erosion

Water Erosion

The Tragedy of the Commons

A situation where individuals, acting in their self-interest, deplete or degrade a shared resource, leading to its eventual destruction or depletion.

Porosity

The measure of how much space is within a material. It determines the ability of a substance to hold or transmit fluids, gases, or heat.

Soil Permeability

The ability of soil to allow water or other liquids to flow through it. It is determined by the size and arrangement of soil particles.

Soil Horizon

The distinct layer in the soil profile, each with unique characteristics and properties, formed by the accumulation and transformation of materials over time.