Introduction to Ecology

Introduction to Ecology

• Ecology is the study of how organisms interact with each other and their environment.
• Studying ecology helps us fulfill God's command to care for His creation.
• The four levels of organization in ecology are: ecosystems, communities, populations, and species.
• Habitat is the place where an organism lives, while biological niche is the role an organism plays in its ecosystem.
• Abiotic factors are non-living components of an ecosystem (e.g., temperature, water, sunlight, soil), while biotic factors are living components (e.g., plants, animals).

Abiotic Factors

• Abiotic factors can be influenced by biotic factors. For example, plant growth can affect the amount of sunlight reaching the lake bottom, impacting water temperature.

Global Systems

• The four major global systems are the atmosphere, biosphere, hydrosphere, and geosphere.
• These systems are interconnected and influence each other.
• Global change can result from natural processes or human activities.

Biological Indicators of Water Quality

• Biological indicators are organisms that can be used to evaluate the health of an aquatic ecosystem.
• Benthic macroinvertebrates (insects) are commonly used indicators, with different species indicating different water quality levels.
• Other indicators include birds and beavers.

Water Distribution

• Oceans account for 97.3% of the Earth's water.
• Other significant sources include ice caps (2.05%), groundwater (0.6%), lakes (1%), and rivers (0.00001%).

Impacts of Sin on Aquatic Ecosystems

• Pollution is a major indicator of the unhealthy state of aquatic ecosystems.
• Types of pollution include sediment, nutrient, chemical, pathogen, plastic, and thermal pollution.
• Human activity significantly impacts water quality.

Water Movement in the Earth System

• The hydrological cycle describes the continuous movement of water through the atmosphere, biosphere, hydrosphere, and geosphere.
• This cycle includes processes like runoff, infiltration, percolation, seepage, stream flow, groundwater flow, plant uptake, evapotranspiration, animal uptake, sublimation, human usage, and groundwater storage.
• Human activities can both positively and negatively impact the water cycle.
• Point sources of pollution are identifiable locations where pollution enters a water body (e.g., factory discharge), while nonpoint sources are dispersed areas where pollution enters (e.g., agricultural runoff).

Monitoring Water Quality

• Watersheds are areas of land where all the water drains into a common body of water.
• The watershed approach is essential for monitoring water quality because it considers the entire ecosystem.
• Biological, physical, and chemical indicators are used to assess water quality.

Physical Indicators of Water Quality

• Transects are used to measure physical factors along a stream.
• Temperature is a crucial factor, as thermal pollution can negatively impact aquatic life.
• Transparency indicates the amount of sediment and other suspended particles in the water, which can block sunlight and harm aquatic organisms.
• Velocity, depth, and width also affect water quality.

Chemical Indicators of Water Quality

• Water is essential for life due to its unique structure and properties.
• Water molecule has a chemical formula of H2O and a bent shape due to the polar covalent bonds.
• Hydrogen bonds form between water molecules due to the polarity, creating unique properties.

Properties of Water

• Universal solvent: Water's polarity allows it to dissolve many substances.
• Cohesion: Water molecules stick together, creating surface tension.
• Adhesion: Water molecules stick to other substances, allowing for capillary action.
• High heat of vaporization: Water requires significant energy to evaporate, making it act as a heat sink and regulate temperature.
• High specific heat: Water resists rapid temperature changes, helping aquatic systems maintain a stable temperature.
• Three states of matter: Water exists as a solid (ice), liquid (water), and gas (water vapour), each having a distinct density.
• Neutral pH (7): Pure water has a pH of 7, indicating a balance between hydronium (H3O+) and hydroxide (OH-) ions.