BIOLOGY NOTES. Ecology is the study of how organisms interact with each other and their environment

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1 BIOLOGY CHAPTER 1: ECOLOGY SUBTOPIC : 12.1 Introduction to ecology. LEARNING OUTCOMES: Define basic terminologies in ecology. - niche, habitat, organism, population, community, ecosystem, biome, biosphere.. Definition of ecology Ecology is the study of how organisms interact with each other and their environment Terminologies Terminologies Definition Niche Niche is the status or role of an organism in its habitat /environment. Habitat Organism Population The systems working together with complexity make up a complex living organism. Community All the organisms that inhabit a particular area; an assemblage of populations of different species living close enough together for potential interaction. Ecosystem Biome Biosphere Any of the world secosystem types, often classified according to the predominant vegetation for terrestrial biomes and the physical environment for aquatic bioms, and characterized by adaptations of organisms to the particular environment. 1 KMPk

2 BIOLOGY DIAGRAM 1. Level of organization in an ecosystem. 2. Component of biosphere. 2 KMPk

3 SUBTOPIC : 12.2 Ecosystem concept LEARNING OUTCOMES: Explain ecosystem concept. a) Explain the components of the ecosystem with example: i. Biotic component ii. Abiotic components iii. Interaction between / among biotic components iv. Interactions between biotic and abiotic components b) Describe the following ecosystem structures: i. Lake ecosystem ii. Terrestrial ecosystem of tropical rainforest Definition of ecosystem concept. Biotic components Definition according to Odum (1969) Basic functional unit of nature including both organisms and their non-living environment. Each interacting with other and influencing each other s Both necessary for maintenance and development of the system. Autotroph / producer -An organism that obtains organic food molecules without eating other organism or substances derived from other organism. -In terrestrial ecosystems- green plants are the producers. -In aquatic ecosystems phytoplankton (algae & blue green bacteria). Heterotroph / consumer -An organisms that obtains organic food molecules by eating others organisms or substances derived from them. -Heterotroph can be divided into 4 type of organisms: Herbivore (primary consumer) Carnivore (secondary consumer) - An animal that mainly eats other animals. Predators Scavengers Omnivore Detritivore An organism (such as an earthworm or crab) that feed on small fragments of dead organisms and on waste matter of animals and plants. 3 KMPk

4 Abiotic components Decomposer -An organism that absorb nutrients from nonliving organic material such as corpses, fallen plant material and the wastes of living organisms. Atmosphere - Hydrosphere - Lithosphere - Interactions between/among biotic components Competition -The interaction among two or more individuals that attempt to use the same essential resource, such as food, water, sunlight, or living space. -can be divided into two: Interspecific intraspecific Parasitisme -A symbiotic relationship in which one organism (parasite) benefits and the other (host) is adversely affected. -can be divided into two: Endoparasites Ectoparasites Commensalisme - Mutualisme -A symbiotic relationship in which both participants benefit. Predation -Relationship in which one organism (predator) kills and devours another organism (prey). Interactions between biotic and abiotic components -Ecosystem create biophysical feedback mechanisms between living (biotic) and non-living (abiotic) components of the planet. -These feedback loops regulate and sustain local communities, continental climate systems, and global biogeochemical cycles 4 KMPk

5 Lake ecosystem -Zonation of lake ecosystem: i) base on light penetration ii) base on distance from shore and depth of water iii) base on open water i) Base on light penetration Photic zone - Upper part of lake or marine environment - light is sufficient for photosynthesis - Biotic components: almost all are the primary producer (high productivity occurs) Aphotic zone *Compensation point :- -The depth at which light penetrating the water creates the same balanced effect -Point in between photic and aphotic zone. - Where the rate of photosynthesis equal to the rate of respiration ii) Base on distance from shore and depth of water Littoral zone -Area near the shore that receives sunlight, extending down to the depth where rooted plants stop growing - Diversity greatest here: i) very diverse animal ii) diversity of plant Limnetic zone -Open surface waters, away from the shore -It is above the profundal zone -This is the main photosynthetic body of the lake 5 KMPk

6 iii) Base on open water Pelagic zone Benthic zone -A portion of freshwater ecosystem that occurs in open water, away from the shore - Located at the bottom of all aquatic biomes -Made up of sand and organic and inorganic sediments Lake Stratification - the separation of lakes horizontally into three layers based on temperature: Epilimnion Thermocline or metalimnion Hypolimnion Terrestrial ecosystem of tropical rainforest Strata Type of tree Animal in community Emergent Canopy Shrub Herb Taloid 6 KMPk

7 BIOLOGY DIAGRAM 3. Lake ecosystem. 4. Lake stratification. 7 KMPk

8 5. Terrestrial ecosystem of tropical rainforest. 8 KMPk

9 SUBTOPIC : 12.3 Energy flow through ecosystem LEARNING OUTCOMES: Describe food chain, food web and ecological pyramid in relation to trophic levels and energy transfer. Food chain Food web Trophic level -In a food chain, energy and nutrients are passed from one organism to another. -It represents one path of energy flow through an ecosystem. -Most food chains are interconnected. -Most animals will utilize several food sources. -Shows the flow of biomass and energy from one trophic level to the next. -The position that an organism occupies in a food chain. -Many animals feed at several different tropic levels. Trophic level 1 Producer Eg: Plants Trophic level 2 Trophic level 3 Trophic level 4 Ecological pyramid -A diagram representation of the relative energy value at each trophic level / the flow of energy through the food chain. -Three types of pyramid have been used:- Pyramid of number -Based on counting the numbers of organisms at each trophic level. -The number of organisms less than produces because small proportion of energy taken in by an organism. -Parasitic food chains give inverted pyramids. Pyramid of biomass 9 KMPk

10 Pyramid of energy -Energy pyramid indicates total amount of energy present in each trophic level. -Also shows loss of energy from one trophic level to the next. -Shows clearly that energy transfer from one trophic level to next accompanied by decrease due to waste, respiration and death. Calculation on energy - Gross Primary Production(GPP) : the rate at which an ecosystem's producers capture and store a given amount of chemical energy as biomass. -Net Primary Production (NPP) : referred to the remaining fixed energy -Ra : autotrophic respiration (respiration by plant) NPP = GPP - Ra Why food chain consists less than five trophic level? -When energy flows from one trophic level to another, energy lost through respiration, excretion and heat to surroundings. 10 KMPk

11 BIOLOGY DIAGRAM 6. Food chain 7. Food web 8. Trophic level 11 KMPk

12 9. Ecological pyramid 10. Energy loss 12 KMPk

13 SUBTOPIC : 12.4 Biogeochemical cycle LEARNING OUTCOMES: Describe biogeochemical cycle components (cycling pool and reservoir pool). What is biogeochemical cycle? Component in biogeochemical cycle -Biogeochemical is the relation between biological and geological/ earth components and chemical changes. -Biogeochemical cycles is the second major function of ecosystem (along with energy flow). -Each cycle summaries the movement of chemical elements through the living components of ecosystem -Eg. : carbon cycle, nitrogen cycle, oxygen cycle, sulphur cycle. 1. Reservoir pool 2. Cycling pool Carbon cycle -Carbon cycle: carbon dioxide fixation by plants and the counterbalancing release of carbon dioxide in respiration. -Reservoir pool : -Cycling pool : Photosynthesis Cellular respiration -Carbon enters plants, algae, and cynobacteria as CO2 which is incorporated into organic molecules by photosynthesis. Combustion Burning of fossil fuel Decomposition Erosion of limestone 13 KMPk

14 BIOLOGY DIAGRAM 11. Carbon cycle 14 KMPk

15 SUBTOPIC : 12.5 Conservation and management LEARNING OUTCOMES: a) Explain sustainable development. b) Discuss threats to biodiversity in Malaysia c) Discuss conservation of biodiversity in Malaysia Sustainable development -Sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs. Sustainable forestry Sustainable algriculture Sustainable fishery -crop rotations -contour farming -strip farming -terracing Threats to biodiversity in Malaysia Conservation and preservation -Habitat loss or conversion and economic exploitation of natural resources have been the primary cause of biological diversity loss in Malaysia to date. -Now more likely to be industrial pollution rather than habitat loss due to ongoing structural changes in the Malaysian economy. -Eg. leatherback turtle, milky stork, slipper orchid Conservation -Conservation is how humans impact organisms and of the development of ways to protect biological diversity. -Safeguarding populations of endangered species. -Preserving entire ecosystems and landscapes. Preservation -Preservation implies complete protection, with little human disturbance. -Wilderness and certain unique habitats for wildlife must be kept intact. Ecosystem management -They are various techniques of conservation used in ecosystem management, eg:- i) Nature reserves and national parks. 15 KMPk

16 ii) Planned land use iii) Legal protection of endangered species Eco-friendly practices Conservation of biodiversity in Malaysia -Practice of biological control such as using the owl as the guard to kill or prevent mice and rats from destroying the crop. -Practice of crop planting rotation - growing a series of dissimilar/different types of crops in the same area in sequential seasons. -Tagal System in Sabah open and close seasons in fishing activities. In-situ conservation Ex-situ conservation 16 KMPk