C astlehead H igh S chool Environmental Biology & Genetics Energy Flow Intermediate 2

C astlehead H igh S chool Components of an ecosystem Habitat = where an organism lives Population = organisms of one type or species Community = sum total of all populations of animals, plants etc in an area Ecosystem = community + habitat LEARN THESE DEFINITIONS!!!

C astlehead H igh S chool Niche role that an organism has in an ecosystem Herbivore - plant eater Carnivore - meat eater Omnivore - eats meat & plants Decomposer - feeds on dead or decaying organisms Predator - hunts other animals for food Prey - hunted by other animals as food

C astlehead H igh S chool Flow of Energy Sun - source of all energy in an ecosystem Producer - green plant; able to make its own food (chemical energy) using light energy from the sun Consumers - animals that eat the plants to get the energy stored in the plants. These animals are then eaten by other animals. Sun Green Plant Eater Meat Eater producerprimary consumer secondary consumer

C astlehead H igh S chool Food Chains Shows the way energy is passed along from organism to organism. The direction of energy flow is shown by an arrow Always start with a producer At each stage some of the energy is lost.

C astlehead H igh S chool Food Webs A food web shows many food chains & the complex relationships between organisms in an ecosystem Grass Rabbit FoxOwl Field mouse Hawk Producers Primary Consumers Secondary consumers

C astlehead H igh S chool Energy Loss Energy is lost from a food chain through movement, heat and undigested food At each link in a chain approximately 90% of the energy available is lost and only 10% is passed on to the next organism in the chain. Shorter food chains are therefore more efficient than longer food chains

C astlehead H igh S chool Pyramid of Numbers The producers in a food chain are usually found in the highest numbers although a single large plant such as an oak tree may be the producer The final consumer is usually the least numerous This numerical relationship can be represented as a pyramid of numbers

C astlehead H igh S chool Pyramid of Numbers Algae (single celled green plants millions present) Water fleas (hundreds present) Sticklebacks small fish less than 100 Pike 2 present The size of each level depends upon how many organisms are involved in the food chain. The producer always goes at the bottom.

C astlehead H igh S chool Pyramid of Biomass The biomass of a population is the total mass of living matter The biomass of a producer is greater than the biomass of the primary consumer which is greater than the biomass of the secondary consumer etc. This can also be represented by a pyramid

C astlehead H igh S chool Pyramid of Biomass Algae ( 10 Tonnes) Water fleas (1 Tonne) Sticklebacks 5,000 Kg Pike 20 Kg

C astlehead H igh S chool Pyramid of Energy A more reliable comparison between organisms can be made based on productivity A pyramid of energy shows the quantity of energy produced by each level Expressed as in kilojoules

C astlehead H igh S chool Pyramid of Energy Algae (3000kj energy from sun absorbed by algae) Water fleas (300Kj passed on ) Sticklebacks 30Kj Pike 3Kj Only 10% of energy is passed on from one level to the next