Ecology & Ecosystem: Habitats, Factors, Food Chains, Organism Interactions, Slides of Biology

Download Ecology & Ecosystem: Habitats, Factors, Food Chains, Organism Interactions and more Slides Biology in PDF only on Docsity! Introduction ∗ Habitat: the place where an organism occurs ∗ Population: a group of organisms of the same species in an area ∗ Community: all population & plants in the same area Docsity.com Introduction ∗ Ecosystem: a stable, self-supporting system which consists of communities interacting with each other ∗ Ecology: the study of the interactions between living organisms & their environment Docsity.com What is Environment ? Composed of 2 components, Physical Factors & Biotic Factors, which influence the lives of organisms Docsity.com Priysic¢al Factors Temperature Light Rainfall & Humidity Wind Speed Soil (esp. for plants) pl Docsity.com Biotic Factors Consists of all the other organisms living together in the same habitat Docsity.com Decomposers not shown in food chain consist of Bacteria & Fungi break down organic wastes & dead bodies of other organisms to simpler compounds which are then absorbed by green plants significance: enable the recycling of materials within an ecosystem Docsity.com Trophic Level Green plant Producer First Rabbit Primary Consumer Second Snake Secondary Consumer Third Hawk Tertiary Consumer Fourth Organism Type Docsity.com Producers Primary Secondary Tertiary (plants) ‘Consumers Consumers Consumers (herbivores) (carnivores) {top carnivores) Detrtivores =™ (decomposers and detritus feeders) Docsity.com • Why is there energy loss ? – Uneaten food – Respiration – Egestion & Excretion • ∴ solving the food problem by… – consuming organisms in lower trophic levels – down a level, increase at least 10 times of food available Energy Lost up a Food Chain Docsity.com Pyramids of Biomass Biomass is the total dry mass of organisms at a trophic level 500 Producers Primary Consumers Secondary Consumers 50 1 Docsity.com Effects of DDT  DDT is an effective pesticide  DDT has been used for about 20 years  It had been banned for over 20 years  But, nowadays, the body of every people still has DDT Docsity.com Carbon Cycle Carbon dioxide in air organic substances in plants organic substances in animals absorption & photosynthesis respiration fossil feeding respiration burning incomplete decomposition Docsity.com Nitrogen Cycle nitrate in soil protein in plants protein in animals ammonia nitrogen in air absorption & photosynthesis feeding putrefying bacteria (decomposition) faeces, urine, dead body nitrifying bacteria (nitrification) denitrifying bacteria (denitrification) nitrogen- fixing bacteria Docsity.com Investigation of a Balanced Aquarium Docsity.com Describe the appearance of the water snails and the freshwater plants after a few days if the aquarium is balanced ? Ans: The water snails and the aquatic plants will remain healthy even after a few weeks. lid water water snail freshwater plant Docsity.com What will happen to the aquarium if it is placed in darkness all the time ? Why ? Ans: Both the water snails and the freshwater plants will gradually die since there is no light for the aquatic plants to carry out photosynthesis to make food… lid water water snail freshwater plant Docsity.com What will happen to the aquarium if it is placed in darkness all the time ? Why ? Ans: so the plants cannot survive without food supply. As all aquatic plants died, the water snails also die due to starvation. lid water water snail freshwater plant Docsity.com Commensalism • one gets (physical) benefit, one feels no effect • organism benefited: Commensal • organism with no effect: Host • easy separate from each other • eg. barnacle on crab (barnacle gets transport) Docsity.com Mutualism • both obtain benefits • not easy separate (even cannot be separated) • e.g.1. lichen (mutualism of specific algae & fungi) – fungi absorb moisture from air and moist the algae – algae provide carbohydrates for the fungi Docsity.com Mutualism • e.g.2. Nitrogen-Fixing Bacteria & Leguminous Plants – bacteria fix atmospheric nitrogen to nitrogenous compounds for the plant – the plant provides carbohydrates to bacteria Docsity.com