Human Ecology and Population Dynamics

Interdisciplinary Study of Environment

• Interdisciplinary study of the relationship between humans and their natural, social, and built environments.
• Branch of ecology that works to understand patterns and processes of change over time or space for populations of a single species.

Population Ecology

• Population: a group of organisms of the same species that occupy the same area at the same time.
• Factors affecting population:
  • Population size: total number of individuals.
  • Population density: number of individuals per unit area.
  • Dispersion pattern: how individuals are distributed in space at a given time.
  • Demographics: study of population that includes parameters such as birth and death rates, and gender ratio.

Population Growth

• Types of population growth:
  • Exponential growth (J-shaped curve): growth occurs in an ideal environment with unlimited resources.
  • Logistic growth (S-shaped curve): growth occurs when the population approaches a finite carrying capacity.

Limiting Factors

• Density-dependent factors: factors that depend on population size, such as competition, predation, and disease.
• Density-independent factors: factors that affect populations regardless of size, such as natural disasters, climate, and human activities.

Age Structure

• The proportionate number of people in different age categories in a given population.
• Survivorship curves: graphs that show the fraction of a population that survives from one age to the next.

Earth's System

• The Earth is composed of different systems, including:
  • Atmosphere: protective layer of gases that shelters all life on Earth.
  • Hydrosphere: consists of all water bodies, including oceans, rivers, and lakes.
  • Biosphere: contains all living organisms.
  • Geosphere: solid portion of the Earth, including the crust, mantle, and core.

Atmosphere

• Layers of the atmosphere:
  • Troposphere: lowest layer of the atmosphere, extending from the ground to 10 km high.
  • Stratosphere: next layer, extending from 10 km to 50 km high.
  • Mesosphere: third layer, extending from 50 km to 130 km high.
  • Thermosphere: hottest layer, extending from 130 km to outer space.
  • Exosphere: outermost layer, where atmosphere interacts with outer space.

Hydrosphere

• Consists of all water bodies, including oceans, rivers, and lakes.
• Water cycles through evaporation, condensation, and precipitation.

Biosphere

• Contains all living organisms.
• Interacts with other systems to support life on Earth.

Geosphere

• Solid portion of the Earth, including the crust, mantle, and core.
• Divided into the lithosphere (outer rigid layer) and the asthenosphere (semi-fluid layer).

Plate Tectonics

• Theory that explains how major landforms are created.
• Plates move apart, collide, or slide past each other, causing earthquakes, volcanoes, and mountain formation.

Core

• Innermost part of the Earth, composed of two layers:
  • Outer Core: liquid iron and nickel, responsible for Earth's magnetic field.
  • Inner Core: solid, dense center of the Earth.

Ecology and Ecosystem

• Ecology: branch of biological sciences dealing with interactions between organisms and their environment.
• Ecosystem: geographic area where biotic and abiotic factors interact.

Levels of Organization

• Levels of organization in ecology:
  • Organism: individual living thing.
  • Population: group of organisms of the same species.
  • Community: association of populations of different species.
  • Ecosystem: geographic area where biotic and abiotic factors interact.
  • Biosphere: contains all living organisms.

Biological Basis of Life

• Cells: basic units of life.
• Molecules: building blocks of cells.
• Organisms: individual living things.

Ecological Relationships

• Types of ecological relationships:
  • Competition: interaction between individuals for a common resource.
  • Predation: one species eats another.
  • Symbiosis: close, prolonged association between different species.
  • Mutualism: type of symbiosis where both species benefit.
  • Commensalism: type of symbiosis where one species benefits, the other is not affected.
  • Parasitism: type of symbiosis where one species benefits, the other is harmed.

Energy Transfer

• Food chain: sequence of transfer of matter and energy in the form of food from organisms to organisms.
• Food web: all interconnected and overlapping food chains in an ecosystem.
• Pyramid of energy: graphical representation of the amount of energy at each trophic level of a food chain.
• Law of 10%: states that only 10% of the energy available gets passed onto the next level of consumers.

Ecological Succession

• Series of changes that occur in an ecological community over time.
• Process of ecological succession:
  • Nudation: formation of a nude or bare area.
  • Invasion: pioneer species reach the newly created area.
  • Competition and co-action: species compete for resources and niches.

This quiz explores the relationship between humans and their environments, including population size, growth, stability, and decline. It covers the study of factors that affect population dynamics and the patterns and processes of change over time or space.