Ecology Basics and Organization

Ecology Definition

• Ecology is the study of organisms, their environment, and how they interact with each other and their environment
• It is studied at different levels, like organism, population, community, biosphere, and ecosystem
• The Greek word "oikos" means "house" or "habitat". "Ecology" combines "oikos" and "-logy" which means "study".
• It is the study of interactions between organisms and their physical and chemical environment

Organization of Biological Life

• Species: Group of similar organisms that can interbreed and produce fertile offspring
• Population: Organisms of the same species in the same area
• Communities: Different populations living together in a defined area
• Ecosystem: All organisms in a particular area along with their non-living environment (biotic and abiotic factors)
• Biome: Group of ecosystems that share similar climates and plant communities

Types of Ecology

• Global Ecology: Studies interactions between Earth's ecosystems (land, atmosphere, oceans) and their planetary impact
• Landscape Ecology: Studies the energy, material, and organism exchange within and across ecosystems, including the effects of human activities
• Ecosystem Ecology: Examines the relationships between living and non-living components within an ecosystem
• Community Ecology: Studies populations of different species interacting within a certain geographical area
• Population Ecology: Studies factors that affect population size and distribution, such as birth rates, immigration, death rates, and emigration
• Organismal Ecology: Examines how individual organisms interact with their physical environment, including their behavior, physiology, etc.
• Molecular Ecology: Study of the interaction between the production of proteins, DNA and the environment

Human Activities Affecting Health and Environment

• Household wastes
• Freshwater pollution
• Land use and agricultural development
• Erosion
• Industrialization
• Energy generation

Environmental Threats to Human Health

• Traditional hazards: Associated with a lack of development
• Modern hazards: Associated with unsustainable development

Introduction to Ecological Principles

• Biomes: Large geographic areas with specific climates, plants, and animals
• Ecosphere: All living organisms and their environment (atmosphere, lithosphere, hydrosphere)
• Limiting Factor: Environmental element that restricts population growth/distribution/abundance
• Tolerance: An organism's lessened response to a specific environmental factor over time
• Niche: An organism's role/position within its community
• Biotic Community: A natural grouping of plants and animals in a specific habitat

Population

• Population is a set of individuals of the same species living at one given time in one particular area
• It is not a static entity; its size and characteristics continuously change in response to environmental pressure
• It is defined by birth, death rates, migration from or to the area (immigration/emigration)

Ecological Dominance

• Organisms that exert a major role in controlling an ecosystem
• Organisms that exert a powerful influence on a community

Ecosystem Successions

• Gradual changes in the ecosystem over time as one community replaces another.
• Primary succession: Initial development of a community on a previously unoccupied site (e.g. rocky areas, sand)
• Secondary succession: Community development in a disturbed region that still has some soil or life forms

Concepts of Range and Limits

• Law of the minimum (Liebig's Law): Growth rate is limited by the scarcest nutrient
• Law of tolerance (Shelford's Law): Species distribution is determined by its ability to withstand variation in environmental factors

Habitat/Ecological Niche

• Habitat: Environment where an organism lives.
• Ecological niche: The functional role of an organism within its community

Energy Flow

• Transfer of energy through the ecosystem begins with photosynthesis (converting solar energy to chemical energy)
• Energy moves through ecosystems through trophic levels (producers, consumers, decomposers)
• At each transfer, there is a significant loss of energy (approximately 90%)

Biogeochemical Cycles

• Continuous cycling of essential elements through both living and non-living parts of the ecosystem. Examples include carbon and nitrogen cycles

The Carbon Cycle

• Carbon is a fundamental component of organic molecules
• Carbon enters the ecosystem through photosynthesis, then moves amongst living and non-living forms and returns to the atmosphere.
• The combustion of fossil fuels adds large amounts of carbon dioxide to the atmosphere

The Nitrogen Cycle

• Nitrogen is essential for organisms because it is crucial in protein and DNA synthesis
• Nitrogen gas (N2) in the atmosphere cannot be directly used by many organisms
• Certain bacteria convert nitrogen gas into usable forms

The Phosphorus Cycle

• Phosphorus is vital for DNA and ATP production
• Phosphorus generally remains within the soil and rocks for a prolonged period before returning to the atmosphere

Ecological Definitions

• Natality: Birth rate
• Biotic potential: Maximum rate of growth
• Environmental resistance: Pressure that limits growth
• Carrying capacity: Sustainable environment for a population
• Age structure: Relative number of individuals at different ages
• Emigration: Leaving the population
• Immigration: Joining the population
• Exponential growth: Population growth in doubling rates
• Survivorship: Proportion of individuals that survive to a particular age
• Density-dependent factor: Environmental factor that changes with the population density
• Density-independent factor: Environmental factor that does not change with population density
• Doubling time: Time taken for population to double

Ecosystem

• Community of organisms and their physical environment functioning together
• Two major components in ecosystem; biotic and abiotic

Test your knowledge on the fundamentals of ecology, covering definitions, levels of organization, and types of ecological studies. This quiz will explore concepts from species to ecosystems and the interactions within them. Perfect for students looking to enhance their understanding of ecological principles.