Ecosystems, Habitats and Biodiversity

• Ecosystems encompass all living things, like plants, animals, and microorganisms, interacting with each other and their non-living environment such as weather, earth, sun, soil, climate, and atmosphere.

Habitats

• A habitat is the natural environment where a plant, animal, or other organism lives.
• Habitats provide everything an organism needs to survive, including food, water, shelter, and space.
• Different types of habitats include forests, grasslands, deserts, aquatic habitats (oceans, lakes, rivers).
• Each habitat has specific characteristics (climate, soil type, available resources) that determine which organisms can live there
• A microhabitat is a very small, specialized habitat, like the space under a rock or inside a rotting log

Biodiversity

• Biodiversity refers to the variety of life on Earth at all its levels, from genes to ecosystems, and can encompass the evolutionary, ecological, and cultural processes that sustain life
• A higher biodiversity indicates a healthier and more stable ecosystem, capable of withstanding environmental changes
• High biodiversity provides many ecosystem services such as pollination, water purification, and climate regulation
• Biodiversity can be threatened by habitat destruction, pollution, climate change, and invasive species

Food Chains

• A food chain illustrates the flow of energy from one organism to another in an ecosystem
• It always begins with a producer, usually a plant, which makes its own food through photosynthesis
• Producers are eaten by consumers, which can be herbivores (plant-eaters), carnivores (meat-eaters), or omnivores (both plant and meat-eaters)
• Decomposers, like bacteria and fungi, break down dead organisms and return nutrients to the soil, completing the cycle
• The arrows in a food chain show the direction of energy transfer
• Examples of food chains include: grass → grasshopper → frog → snake → hawk or algae → zooplankton → small fish → larger fish

Energy Flow

• Energy flow in an ecosystem is linear, starting with the sun
• Producers convert solar energy into chemical energy through photosynthesis
• When consumers eat producers or other consumers, they obtain energy
• Energy is lost at each level of the food chain as heat due to metabolic processes
• Only about 10% of the energy is transferred from one trophic level to the next.
• This energy loss limits the length of food chains, as there is not enough energy to support many trophic levels

Interdependence

• Interdependence describes how organisms in an ecosystem rely on each other for survival.
• Plants depend on animals for pollination and seed dispersal.
• Animals depend on plants for food and shelter.
• Decomposers depend on dead organisms for food, and in turn, provide nutrients for plants.
• Changes in one part of an ecosystem can affect other parts due to these interdependencies.
• If one species declines, it can impact other species throughout the food web or ecosystem.