1 / 19

Ecosystems and Energy Transfers

Ecosystems and Energy Transfers. WONG HONG CHING. Index. 1. Definition of key words 2. Energy transfers in ecosystems 3. Ecological pyramids. 1. Definition of key words. Ecosystem Population Community Habitat Niche Environment. Ecosystem. Ecosystem stands for Ecological system.

lacy
Download Presentation

Ecosystems and Energy Transfers

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Ecosystems and Energy Transfers WONG HONG CHING

  2. Index • 1. Definition of key words • 2. Energy transfers in ecosystems • 3. Ecological pyramids

  3. 1. Definition of key words Ecosystem Population Community Habitat Niche Environment

  4. Ecosystem • Ecosystem stands for Ecological system. • It is an ecological unit which includes all living organisms and the abiotic factors that surround the organisms, results from the dynamic interactions abiotic and biotic factors. • The abiotic factors: • Temperature • pH • Light intensity • Oxygen level • Humidity • Rainfall • The biotic factors: • Animals • Plants • Micro-organisms

  5. Population & Community • Population refers to all the organisms of the same species in a area. • Community refers to all living organisms of different species living in a given area. • Living organisms interact with each other and are interconnected by food chains or food webs.

  6. Habitat • Habitat refers to the place where the communities live. • Examples of habitats: • Forest • Sea • Rock shore • Soil

  7. Niche • It is a word which is used to describe the relational position of a species in an area. • It refers to the roles of an organism in an area. • Different species have different roles, niches. • Roles: • What it eats • Where it lives • When it is active • When it eats

  8. Environment • Environment is the conditions surrounding the organisms. • The conditions include both abiotic factors and biotic factors. • The abiotic factors: • Temperature • Rainfall • pH • Light intensity • Oxygen level • Humidity • The biotic factors: • Predation by other organisms • Competition of nutrients, food

  9. Energy transfers Cycle • First step: • Solar energy  Plants (Act as producers) • Second step: • Producers’ energy  Primary consumer (herbivores) • Third step: • Primary consumers’ energy  Secondary consumers (carnivores) • Forth step: • Secondary consumers’ energy  Tertiary consumers • Final step: • When tertiary consumers die, the energy and nutrients are returned to the soil by saprotrophic organisms which feed on dead organisms. • Decomposers: Start the cycle again

  10. Energy Transfers in Ecosystem • Is the energy totally transferred between different trophic levels? • The answer is no. • Only 10% energy is transferred between different trophic level. WHY?? • 30% of energy is used in respiration. • 60% of energy is lost in excretion of waste products, like faeces, urine, gas. • Amount of energy stored and transferred to another trophic level: • 100% - 30% - 60% = 10% • No food chain can exceed more than 5 links. • Otherwise, the consumers at the end of food chain cannot get enough food and energy.

  11. Ecological Pyramids • What is ecological pyramids? • They are the graphs which are used to show the relationship between energy and trophic levels of an area. • Three types of pyramids: • Pyramid of number • Pyramid of biomass • Pyramid of energy

  12. Feature: Primary producers are at the bottom.

  13. Pyramid of number • Feature: • It is a ecological pyramid which shows the number of organisms in different trophic levels. • Advantage: • Just counting the number of organisms, is easy to produce. • Disadvantages: • The pyramid shape is messed up by small amount of big producers (like trees) and large amount of tertiary producers (like fleas).

  14. Large amount of small tertiary consumers. Small amount of large producers. Abnormal cases of pyramids of number

  15. Pyramid of biomass • It is a ecological pyramid which measures the dry mass of organisms in different trophic levels. • The unit of dry mass is kg/m2 • Advantage: • Pretty accurate, often have a normal pyramid shape. • Disadvantages: • Difficult to get the data. (Need to kill the organism and evaporate all of it’s water inside the body) • If the producers have small sizes, short life and reproduces quickly, then the pyramid shape is distorted.

  16. Pyramid of energy • It is a ecological pyramid which measures the amount of energy in the organisms in different trophic levels. • The unit is kJ/m-2/yr-1 • It is the most accurate among other pyramids. • However, it is very difficult to measure the amount of energy in the organism.

  17. http://ecokids.ca/pub/eco_info/topics/frogs/chain_reaction/index.cfmhttp://ecokids.ca/pub/eco_info/topics/frogs/chain_reaction/index.cfm http://www.arcytech.org/java/population/facts_foodchain.html Bibliography

More Related