Ecology and Ecosystems

Ecology

• Study of relationships between living organisms and the environment

Ecosystems

• All living organisms in a specific area and their physical/chemical environments
• Can be large or small, composed of biotic and abiotic parts

Biotic Factors

• All living things/components of an ecosystem, including their products and remains
• Examples: birds, flowers, people, wood, poop, spider webs, dams

Abiotic Factors

• All non-living components of ecosystems
• Examples: air, wind, rocks, water, soil, temperature, sunlight

Earth's Spheres

• The Atmosphere
  • Layer of gases surrounding the Earth
  • 78% nitrogen, 21% oxygen, and 1% other substances
  • Functions: temperature moderation, keeping the Earth warm
• The Lithosphere
  • The Earth's crust

Limiting Factors

• Any factor that limits the size of a species population
• Abiotic Limiting Factors
  • Temperature, nutrient availability, light availability, water availability, oxygen availability, salinity, pH
• Biotic Limiting Factors
  • Species interactions or ecological relationships
  • Examples: predator-prey cycles, competition, mutualism, commensalism, parasitism

Predator-Prey Cycles

• Predator eats prey, leading to increased predator population and decreased prey population
• Eventually, predators run out of food, and prey population increases

Competition

• Two individuals compete for the same limited resource
• Examples: lions and cheetahs competing for the same prey

Mutualism

• Two individuals mutually benefit each other
• Examples: clownfish and sea anemones, sea anemones provide protection for clownfish, and clown fish lure other fish for the sea anemone to eat

Commensalism

• One individual benefits, the other is unaffected
• Examples: barnacles attach to whales and gain access to food sources, whales are unaffected

Parasitism

• One individual lives with/on/inside a host, causing it harm
• Examples: tapeworms are parasites of cats and dogs, tapeworms take nutrients from the host or feed on the host directly

Carrying Capacity

• The maximum number of individuals of a species that an ecosystem can support
• Carrying capacity can increase or decrease if resources are added or taken away

Ecological Relationships

• Photosynthesis and cellular respiration
• Photosynthesis: process by which producers convert light energy into chemical energy
• Cellular respiration: process by which organisms release energy stored in sugar

The Cycling of Matter

• The importance of water
  • Makes up about 70% of the human body
  • Regulates body temperature
  • Cushions internal organs and tissues
  • Lubricates joints and organs
  • Used to eliminate waste
  • Part of blood, carrying oxygen and nutrients
• The water cycle
  • Water evaporates from surface water, forming water vapor
  • Water vapor condenses and falls as precipitation
  • Surface water collects in rivers, lakes, and eventually returns to oceans
  • Plants take in water through their roots and release water through transpiration
• The importance of carbon
  • Found in all living things
  • Building block of all biological molecules
  • Part of muscles, skin, heart, stomach, and other organs