Topic 9

• A population is defined as a group of organisms of the same species living in the same place at the same time
• A community includes all of the populations living in the same areaat the same time
• Interdependence is two or more species depending on each other for survival
• A habitat is where an organism lives
• An ecosystem is defined as all the biotic factors and all the abiotic factors that interact within an area at one time
• • Biotic factors includes all the living components such as plants and animals
• • Abiotic factors includes all the non-living components such as light intensity, mineral ions, water availability
• Abiotic factor: light intensity

  needed by plants for photosynthesis

  More light means increase in photosynthesis and increase in growth rate
• abiotic factor: temprature

  Affects the rate of photosynthesis in plants
• Abiotic factors: moisture levels

  Plants and animals require water to survive
• Abiotic factor: soil pH and mineral content

  Different species are adapted to different soil pH levels and nutrient concentration levels
• abiotic factors:wind intensity and direction

  Wind speed affects transpiration rate in plants

  Transportation affects the rate of photosynthesis as it ensures water and mineral ions are transported to the leaves
• Abiotic factors: carbon dioxide levels for plants

  CO2 required for photosynthesis in plants, affects the rate of photosynthesis
• Abiotic factors: oxygen levels for aquatic animals

  Some animals can only survive in water with high oxygen concentration
• Biotic factors: availability of food

  More food means higher chance of survival and reproducing, population increase
• Biotic factors: new predators

  ecosystem may become unbalanced as there will be less prey
• biotic factors: new pathogens

  The population in an ecosystem will have no immunity or resistance, causing population decline or wiping out
• Biotic factors: competition

  If a species is better adapted, then that species will outcompete the other, continuing until there are too few of the less adapted species to breed successfully