1. Science 20

2. Review Abiotic factors are physical, non living parts of the environment Biotic factors are living organisms in the environment Ecosystems are all the organisms in an area as well as the abiotic factors which they interact

3. Examples of Abiotic and Biotic factors biotic- living dog cat humans fish worms abiotic-nonliving temperature moisture light soil air currents

4. Symbiosis Symbiosis occurs in mainly ecosystems – Is a long lasting ecological relationship that benefits at least one organism of two different species that live in close contact Mutualism – a symbiotic relationship in which both species benefit Commensalism – a form of symbiosis in which one organism benefits, and the other organism is neither helped not harmed Parasitism – a symbiotic relationship in which one organism called the parasite, derives benefits at the expense of another organism called a host

5. Predator – Prey Interactions Predator- Prey Interactions – This is the interaction between two organisms that is not long lasting and the species do not necessarily live together – Predation – an interaction where one organism, the predator, kills and eats another organism, called the prey.

6. Competition – An interaction in which two or more organisms compete for the same limited resource

7. Food Chain and Food Webs Food Chain – a pathway along which food is transferred from one trophic level to the next Food Web – The interconnecting feeding relationships within an ecosystem

10. Energy Pyramid 0.0001% 0.001% 0.01% 0.1% 1 %

11. Biomass Pyramid

12. Pyramid of Numbers

13. Answers to Questions 27 – The term food web comes from how appearance of the chart as it looks like a spider web. Everything is connected to one another throughout it. 28) a) Algae b) Tadpole, mosquito larvae, water flea, and snail c) Frog, dragonfly, stickleback, Northern Pike d) Perch, Giant Water Bug, Grebe, Northern Pike

14. 29 A) The producers are demonstrated as the basis for the food web because it is the only organism connected to the rest. The energy obtained by the other organism is based on the plants or producers B) Herbivores are the second trophic level because they eat the plants (producers) and then they are eaten by other organisms. C) The tertiary organisms as they consume the most secondary organisms which eat the producers.

15. 30) Algae Tadpole, Mosquito, Waterflea, Snail Frog, Dragonfly, Stickleback, Northern Pike Grebe, Giant Water Bug, Perch Northern Pike

16. 3) The arrows show where the energy is transferred. Its shows that the plant is transferring energy to the herbivore etc. 4) Producers are organisms that can make their own food ie plants through photosynthesis. Consumers have to receive food from other organisms. 5) Producers