a. Mutualism is an interaction between two different organisms that live together in which both organisms benefits. b. They obtain nutrition and shelter from each other.
-The Egyptian Plover bird and crocodiles. the Egyptian Plover eats fleas and ticks crocodile as well as food particles stuck between crocodile's teeth.
- Lichen consists of fungi and algae living together. The algae produce food and the fungi provide shelter.
a.Parasitism is an interaction between two organisms that benefits one organism only and harms the other.
e. Example -Tapeworm is a parasite, it lives in human intestine. Tapeworm obtains food and shelter from humans. Human loses weight and becomes weak.
1. Competition is a relationship where organisms compete with each other for food, light, water, shelter, mate or minerals.
2. Stronger organisms are successful in controlling their territory. Weaker and smaller organisms are driven out of the area. 3. Examples: a. flowering plants compete with weeds to obtain water and mineral salt. b. lions in a pride compete for food c. plants in a tropical rainforest compete for basic needs. Taller trees obtain sunlight more easily.
Intra-specific competition. Competition among organisms of the same species.
Examples a. flowering plants compete with weeds to obtain water and mineral salt. b. lions in a pride compete for food c. plants in a tropical rainforest compete for basic needs. Taller trees obtain sunlight more easily.
Inter-specific competition. Competition among organisms of different species.
Type of interaction Species 1 Species 2 Competition (+) (-) Prey predator (+) (-) Parasitism (+) (-) Commensalism (+) (0) Mutualism (+) (+) SUMMARY ©NgFL/SMK DC 61
BIOLOGICAL CONTROL Biological control is a method in which a predator, the natural enemy to a certain pest, is used to control the population of the pest in an area. The aphid is a pest to the gardeners, damaging his plants. The ladybirds helps the gardener by ridding him of these pests 62
Biological control has many advantages as compared with using pesticides. Advantages disadvantages It does not pollute the environment. Takes a long time before any effect is seen It does not kill other organism except the pests The balance of the ecosystem might be disrupted It is cheap and safe to use.
(Owls is a natural predator of rats in Oil Palm) (When the eggs hatch, the ichneumon larvae feed on the body of the host.) (Rearing guppies in a pond to eat mosquito larvae.) BIOLOGICAL CONTROL 64
BIOLOGICAL CONTROL • MEANING :……………………………………………………………. • EXAMPLES A)…………………………… • B)…………………………….. • C)…………………………..
pest predator 1 rat owl 2 mosquito larvae Guppy fish 3 4 5
Advantages disadvantages
FACTORS THAT INFLUENCE POPULATION SIZE IN AN ECOSYSTEM 1. Factors that cause population size to change: DISEASE, THE PRESENCE OF PREDATORS, SOURCES OF FOOD, AND CHANGE OF WEATHER. A) DISEASE – The population of animals and plant decreases when a disease strikes. • Example poultry affected by a disease
B) PRESENCE OF PREDATORS – when the number of predators increases, the number of prey decreases. C) SOURCES OF FOOD –if the sources of food decreases, animal can threatened by extinction
D) CHANGE OF WEATHER – Droughts cause soil to become dry and infertile and increase the risk of forest fires.
CHANGES IN ECOSYSTEM 1. Changes in ecosystem such as limited water supply, animal migration and increase or decrease in population size can upset the balance between population.
2.4 ROLE OF HUMANS IN MAINTAINING A BALANCED NATURE Activity Effects
STEPS TO SOLVE THE EFFECTS OF HUMAN ACTIVITIES ON THE ENVIRONMENT • 1. Enforce laws • 2. Increase public awareness • 3.Practice refuse, reduce, recycle, repurpose, and reuses (5r)