Ecosystems and Environment

• Environment includes all living and nonliving things that surround and affect organisms.
• Ecosystem refers to a community where living organisms interact with their physical environment in a specific area
• Natural ecosystems exist independently in nature, such as forests, lakes, and oceans
• Artificial ecosystems are man-made, including aquariums, gardens, and crop fields

Abiotic Components

• Abiotic components are non-living physical and chemical factors

Physical Factors

• Abiotic physical include air, water, and soil

Chemical factors

• Abiotic chemical include organic compounds like proteins and fats
• Abiotic chemical include inorganic compounds like hydrogen and oxygen

Environment vs Ecosystem

• Environment is defined as the surroundings where organisms live and is inclusive of all external conditions affecting life
• Ecosystem is a system where living (biotic) and non-living (abiotic) components interact, including food chains, webs, and nutrient cycles
• Environments change as organisms move, but ecosystems remain stable regardless of movement

How Ecosystems Work

• Sunlight is the primary energy source in most ecosystems
• Producers, such as plants, create food using photosynthesis
• Herbivores consume plants and are primary consumers
• Carnivores eat animals and are secondary or tertiary consumers
• Decomposers break down dead organisms
• Nutrient recycling returns nutrients to the soil for reuse
• Food chains represent how organisms feed on one another

Biotic components

• Biotic components make up the living organisms in an ecosystem
• These are further broken down into Autotrophs and Heterotrophs

Autotrophs

• Autotrophs are producers that create their own food using abiotic factors.

Heterotrophs

• Heterotrophs that are consumers depend on producers directly or indirectly for food
• Decomposers break down dead plants and animals

Types of Consumers

• Herbivores are plant eaters like goats and deer
• Carnivores are flesh eaters like tigers and crocodiles
• Omnivores consume both plants and animals, like humans

Food Webs

• Food webs are networks of interconnected food chains that demonstrates complex feeding relationships in ecosystems
• Organisms in food webs can be consumed by multiple other organisms

Trophic Levels

• Trophic levels represent the position an organism occupies in a food chain, which is based on its role in the flow of energy
• Autotrophs/Producers (e.g., green plants) are on the first level
• Herbivores/Primary Consumers on the second Level
• Small carnivores/Secondary Consumers on the third level
• Larger carnivores/Tertiary Consumers make up the fourth level

Energy Transfer

• Energy flows through the environment through food chains
• Producers capture sunlight energy and make it available to consumers and decomposers.
• Energy decreases at each trophic level, with only 10% of energy transferred to the next level

The 10% Law of Energy Transfer

• Only 10% of energy from one trophic level is passed to the next in a food chain
• The remaining 90% is lost as heat, used during movement, growth, and other life processes
• Green plants only capture 1% of solar energy
• A large part of energy is lost as heat at each trophic level, hence the 10% rule
• Only 10% of consumed energy converts into biomass and is available to the next level
• Food chains are usually limited to 3-4 levels, because of energy loss
• Producers are the most numerous, and numbers decrease progressively at higher trophic levels

Bio magnification

• Bio magnification refers to the progressive accumulation of harmful chemicals in organisms at higher trophic levels

Food Chains

• Food Chains are a linear sequence of organisms where each feeds on the next, showing one pathway of energy flow
• Due to this, each organism is only linked to one other organism at the next trophic level
• Food Chains are less stable: and are more greatly affected if an organism is removed from the chain
• Energy flows in a single direction (unidirectional)
• Example: Grass -> Grasshopper -> Frog -> Snake -> Hawk

Food Webs

• Food Webs are a complex network of interconnected food chains in an ecosystem, showing multiple pathways of energy flow
• Each organism is connected to multiple organisms at different trophic levels
• Food Webs are more stable: as a result, the removal of one organism has less impact due to having multiple connections
• Energy flows through multiple interconnected pathways
• Example: Grass is eaten by grasshoppers, rabbits, or deer, which are eaten by frogs, hawks, or lions

Ozone

• Ozone is a molecule made of three oxygen atoms that protects Earth from harmful UV radiation
• Ozone (O3) is formed when UV rays split oxygen molecules (O2), and free oxygen atoms combine with O2
• This process occurs in the stratosphere

Depletion of the Ozone Layer

• A sharp decline has been observed since the 1980s due to chemicals like Chlorofluorocarbons (CFCs)
• CFCs are used in refrigerants and fire extinguishers
• The UNEP introduced an agreement to limit CFC production at 1986 levels

Waste Disposal

• Lifestyle improvements have resulted in accumulation of large amounts of waste material

Types of waste

• Biodegradable waste can be broken down into simpler substances by natural processes through microorganisms (bacteria and fungi)
• Examples include food waste, paper, cotton
• Non-biodegradable waste cannot be broken down naturally and remain in the environment for a long time
• Examples include plastic, glass, and metals

Harmful effects of waste

• Ozone depletion
• Air, soil, and water pollution
• Bioaccumulation
• Bio magnification

Methods of Waste Disposal

• Biogas Plant converts biodegradable waste into biogas and manure
• Sewage Treatment cleans drain water before release into rivers
• Landfilling buries and compacts waste in low-lying areas
• Composting converts organic waste into manure
• Recycling processes non-biodegradable waste into new products
• Reuse uses old items again
• Incineration burns waste at high temperatures to form ash
• Improper disposal of plastics and e-waste harms the environment
• Recycling can also have environmental impacts