Environmental Science: MODULE 2

Environmental and Ecological Concept

Ecosystem

A community of living organisms (plants, animals, and microorganisms) in conjunction with the non-living components of their environment (such as air, water, and mineral soil), interacting as a system.

1. Natural

2. Artificial

Ecosystem

Natural

Like forests, rivers, coral reefs, and grasslands

Artificial

Such as urban parks, constructed wetlands, or irrigation systems

1. Producers

2. Consumers

3. Decomposers

Ecosystem is characterized by:

Producers

Autotrophs like plants that convert solar energy into food

Consumers

Organisms that feed on others (herbivores, carnivores, omnivores)

Decomposers

Fungi and bacteria that break down organic matter

1. Terrestrial Ecosystems

2. Aquatic Ecosystems

3. Urban or Built Ecosystems:

Types of Ecosystems

Terrestrial Ecosystems

Found on land (e.g., forests, grasslands, deserts).

Aquatic Ecosystems

Found in water (e.g., rivers, lakes, coral reefs).

Urban or Built Ecosystems

Human-modified environments (e.g., cities, parks, engineered, wetlands).

1. Biotic (Living) Components

2. Abiotic (Non-living) Components:

Components of an Ecosystem

1. Producers

2. Consumers

3. Decomposers:

Biotic (Living) Components:

Producers

Green plants that make their own food through photosynthesis.

Consumers

Animals that eat plants or other animals.

Decomposers

Organisms that break down waste and dead organisms (e.g., bacteria, fungi).

Abiotic (Non-living) Components

Air, water, sunlight, minerals, temperature.

1. Energy Flow

2. Nutrient Cycling

3. Support for Biodiversity

4. Pollution Control

Functions of an Ecosystem

1. Energy Flow

2. Material Cycling

In ecosystems, ___________ and ________________ are fundamental processes that sustain life. Understanding these processes helps engineers design systems that work with, rather than against, natural cycles.

Energy Flow

Energy in ecosystems originates from the sun and flows in a one-way direction through various trophic levels:

1. Producers (Autotrophs)

2. Consumers (Heterotrophs)

3. Decomposers

Trophic Levels

Producers (Autotrophs)

Organisms like plants and algae that convert solar energy into chemical energy via photosynthesis.

Consumers (Heterotrophs)

Organisms that consume other organisms.

1. Primary consumers (herbivores)

2. Secondary consumers (carnivores)

3. Tertiary consumers (top predators)

Consumers (Heterotrophs)

Decomposers

Bacteria and fungi that break down dead organisms and recycle nutrients.

Food Chain

A linear sequence of organisms through which energy flows.

• Example: Grass → Grasshopper → Frog → Snake → Eagle

Food Web

A more complex and realistic network of interlinked food chains

within an ecosystem.

1. Carbon Cycle

2. Nitrogen Cycle

3. Water Cycle

4. Phosphorus Cycle

Biogeochemical Cycles

Carbon Cycle

Moves carbon through the atmosphere, biosphere, and geosphere.

Nitrogen Cycle

Converts nitrogen into usable forms for plants and animals.

Water Cycle

Describes the movement of water through evaporation, condensation, precipitation, and infiltration.

Phosphorus Cycle

Involves the movement of phosphorus through the lithosphere, hydrosphere, and biosphere.

1. The Carbon Cycle

2. The Nitrogen Cycle

3. The Water (Hydrologic) Cycle

4. The Phosphorus Cycle

Major Biogeochemical Cycles

1. Atmosphere

2. Biosphere

3. Hydrosphere

4. Geosphere.

The carbon cycle describes the movement of carbon atoms through the:

1. Photosynthesis

2. Respiration

3. Decomposition

4. Combustion

5. Sedimentation

The Carbon Cycle (Processes)

Photosynthesis

Plants absorb carbon dioxide (CO2) from the atmosphere and convert it into glucose.

Respiration

Plants and animals release CO2 back into the atmosphere through breathing and decomposition.

Decomposition

Organic matter breaks down, releasing carbon to the soil or atmosphere.

Combustion

Burning of fossil fuels and biomass releases stored carbon into the atmosphere.

Sedimentation

Long-term storage of carbon in the form of fossil fuels and carbonate rocks.

The Nitrogen Cycle

Is essential for all living organisms because it is a key component of amino acids and nucleic acids. However, most nitrogen exists in the atmosphere as inert N2 gas, which organisms cannot use directly.

1. Nitrogen Fixation

2. Nitrification

3. Assimilation

4. Ammonification

5. Denitrification

The Nitrogen Cycle (Processes)

Nitrogen Fixation

Conversion of atmospheric N2 into ammonia (NH3) or nitrate (NO3−) via lightning or nitrogen-fixing bacteria.

Nitrification

Ammonia is converted to nitrites (NO2−) and then to nitrates (NO3−) by nitrifying bacteria.

Assimilation

Plants absorb nitrates, and animals obtain nitrogen by consuming plants.

Ammonification

Decomposers break down organic nitrogen into ammonia.

Denitrification

Denitrifying bacteria convert nitrates back into N2 gas, completing the cycle.

The Water (Hydrologic) Cycle

This cycle moves water through the Earth's systems via physical processes. It is vital for maintaining life, weather patterns, and water availability.

1. Evaporation

2. Condensation

3. Precipitation

4. Infiltration

5. Runoff

6. Transpiration

The Water (Hydrologic) Cycle (Processes)

Evaporation

Solar energy causes water to evaporate from oceans, lakes, and soil.

Condensation

Water vapor condenses to form clouds.

Precipitation

Water falls as rain, snow, sleet, or hail.

Infiltration

Water soaks into the ground and recharges groundwater.

Runoff

Excess water flows over land into bodies of water.

Transpiration

Water is released from plant leaves into the atmosphere.

The Phosphorus Cycle

Unlike carbon and nitrogen, phosphorus does not cycle through the atmosphere. It moves slowly through rocks, soil, water, and living organisms. It is crucial for DNA, RNA, and energy-carrying molecules like ATP.

1. Weathering

2. Absorption

3. Decomposition

4. Sedimentation

The Phosphorus Cycle (Processes)

Weathering

Rocks release phosphate ions (PO43−) into the soil.

Absorption

Plants absorb phosphates, which are transferred through the food web.

Decomposition

Organic material breaks down, returning phosphorus to the soil or water.

Sedimentation

Phosphorus settles in water bodies and becomes part of sediments.

Population Dynamics

___________________ refers to the patterns and processes of change in population size and composition over time. It is a key ecological concept that helps scientists and engineers understand how species—including humans— grow, interact, and affect the ecosystems they live in.

In environmental science and engineering, understanding ___________________ is essential to assess environmental pressure, predict resource needs, and plan for sustainable development. Civil engineers, in particular, use population data to design infrastructure such as water supply systems, waste management, and urban planning strategies.

1. Population Size

2. Population Density

3. Birth Rate

4. Death Rate

5. Migration

6. Carrying Capacity (K)

Key Terms and Concepts

Population Size

The total number of individuals in a species within a specific area.

Population Density

The number of individuals per unit area or volume.

Birth Rate

The number of births in a population over a certain period.

Death Rate

The number of deaths in a population over a certain period.

Migration

The movement of individuals into (immigration) or out of (emigration) a population.

Carrying Capacity (K)

The maximum number of individuals an environment can support sustainably.

1. Fertility Rate

2. Mortality Rate

3. Immigration/Emigration

4. Environmental Conditions

Factors Influencing Population Growth

Fertility Rate

Average number of children born to a woman over her lifetime.

Mortality Rate

Influences how long individuals live and thus affects population size.

Immigration/Emigration

Can rapidly change population composition and size.

Environmental Conditions

Food availability, water, space, diseases, and disasters can impact population.

1. Exponential Growth

2. Logistic Growth:

Population Growth Models

Exponential Growth

Occurs when resources are unlimited. The population grows at a constant rate, forming a J-shaped curve.

Logistic Growth

Occurs when resources become limited, forming an S-shaped (sigmoid) curve.

1. Presidential Decree No. 1151 (Philippine Environmental Policy)

2. Republic Act No. 8749 – The Philippine Clean Air Act of 1999

3. Republic Act No. 9275 – The Philippine Clean Water Act of 2004

4. Republic Act No. 9003 – Ecological Solid Waste Management Act of 2000

5. Republic Act No. 7586 – National Integrated Protected Areas System (NIPAS) Act of 1992

6. Republic Act No. 9729 – Climate Change Act of 2009

Key Environmental Laws in the Philippines