ECOLOGY BOOK xD

Sunday 28 December 2008!

HandWritten on; 10:54

THE NEED FOR CONSERVATION

- Conservation is the protection and preservation of natural resources in the environment.

REASONS FOR NECESSARY CONSERVATION

1. To prevent the extinction of plant and animal species.

endangered species (picture from MSN)

2. To maintain a stable and balanced ecosystem. This prevents disruption of natural cycles such as water and carbon cycle and also prevents global warming.

3.To maintain a large gene pool. Many wild pants and animals possess favourable genes. By cross-breeding the different varieties of wild plants and animals, we can improve agricultural produce.

4. To ensure the conservation of marine life as they are a major source of human food.

A giant group (picture from wikipedia)

5. Conservation of scientific value. The study of wildlife provides useful information to humans.

6. Conservation preserves natural scenery and wildlife for people to appreciate. It also maintains natural resources for outdoor recreational activities such as hiking and fishing.

natural scenery (picture from yahoo)

7. To maintain biodiversity. Especially rainforests as it's a house to many species of animals and plants. Many rainforests are also of great economic importance as they are source of raw materials for industries.

- Tropical rainforests provide raw materials for industries. For example, rubber from the latex of rubber trees is used to make tyres.

-Tropical plants provide raw materials for medicinal drugs and natural insecticides. For example, quinine, anti anti-malarial drug from the bark of Cinchona.

-Tropical rainforests provide food. For example rice, pineapple and banana are food plants that were developed from rainforest plants.

rainforest in the blue mountains, australia (picture from Earth encyclopedia)

Saturday 27 December 2008!

HandWritten on; 16:06

IMPACT OF HUMAN ACTIVITIES ON THE ECOSYSTEM.

DEFORESTATION

-Forests are cleared to meet the increasing demands for land and materials such as wood
-Forests are cleared at a much faster rate than they can be replaced.
-Wildlife may lose their homes when forests are cleared.

deforestation in brazil..........................Toco Toucan under threat (pictures from wikipedia)

EFFECTS OF DEFORESTATION

Soil erosion

-The leafy canopy of the trees in the rainforest protects the soil from the impact of falling rain.

-Rainwater is retained and absorbed by the roots of trees and gradually released into streams.

-Without trees, the soil is directly exposed to the force of rain. Topsoil is washed away or eroded during heavy rain.

soil erosion (picture from wikipedia)

Flooding

-Eroded soil may be deposited in rivers and streams, blocking the flow of water.

-The water levels in rivers rise rapidly causing flood.

flooding (picture from earth wikipedia)

Desertification

-When sunlight falls directly onto the soil, water evaporates rapidly from soil which then hardens.

-Plants cannot grow in the soil as the land becomes barren with the topsoil eroded.

-The destruction of land leading to desert-like conditions. Habitats are lost and many species of organisms become extinct.

desertification of land (picture from yahoo)

Climate changes

-Rainwater that is retained and absorbed by roots of trees is lost as water vapour during transpiration.

-The water vapour condenses and falls as rain.

-When trees are cleared, the area becomes dry and warm and annual rainfall decreases.

UNCONTROLLED FISHING PRACTICES

-Humans catch fish for food. As human population increases so does the demand for fish.

-Some species of fish have been caught in large numbers. Their population drastically decreased. (over-fished)

-Modern fishing gear does not distinguish between the targeted catch and immature organisms or unwanted species.

-shrimp or prawn trawlers drag large fishing nets along the seabed. Unwanted species are trapped

trawling (picture from yahoo)

-Scallop dredges scrape teh seabed, destroying coral reefs and organisms that live on seabed

dredging (picture form MSN)

EFFECTS OF UNCONTROLLED FISHING PRACTICES

-Some species of fish will be caught faster than they can be replaced. Young fish caught will not have a chance to grow and reproduce.

-Population will decrease. Other marine organisms that are unintentionally caught often die.

-Some species may become endangered or even extinct.

POLLUTION

-As human populations increase and technology advances, many products of technology is toxic.

-Toxic waste move into air and water, threatening lives of organisms

air pollution from WWII production (picture from wikipedia)

Sewage

-Untreated sewage may contain disease causing bacteria large amount of people may be affected with diseases if they got into drinking water.

-Bacteria grow and multiply rapidly using up all the oxygen causing death of fishes

-Bacteria that do not require oxygen breaks down the organic waste. Bad smelling gases (ammonia) is released durign the process.

sewage (picture yahoo)

Eutrophication

-Syndrome of ecosystem responsesto human activities that fertilize water bodies with nitrogen and phosphates, often leading to changes in animal and plant populations and degrations of water and habitat quality.

-Fertilisers that are not absorbed by crops will be washed away into rivers by rainwater.

-Submerged algae and plants die due to lack of sunlight. Dead bodies of algae and water plants are decomposed by bacteria which multiply and using up the oxygen in water.

-Other organisms such as fish die due to lack of oxygen.

fishes kill as result of eutrophication.Algal bloom in Australia(picture from encyclopedia of Earth)

Inorganic waste

-Industries dump large amounts of inorganic waste products (poisonous metals) into rivers

lnsecticides

-lnsecticides such as DDT (dichlorodiphenyltrichloroethane) are non-biodegradable. They cannot be broken down by micro-organisms. They remain in the soil

-lnsecticides are carried into streams rivers by rainwater and poison fish or animals.

-DDT accumulates in the bodies of consumers which result it to be passed along the food chain, increasing in concentration in the bodies of organisms along the trophic levels (bioamplification)

-Eventually the concentration of DDT in the top consumers accumulates to the extent that the top consumers suffer toxic effects due to bioaccumulation

Friday 26 December 2008!

HandWritten on; 14:13

THE CARBON CYCLE

-The carbon cycle is the biogeochemical cycle by which carbon is exchanged among the biosphere pedosphere, geosphere, hydrosphere and atmosphere of the Earth.

REMOVAL OF CARBON DIOXIDE FROM THE ENVIRONMENT

Green plants absorb carbon dioxide from the atmosphere during photosynthesis and use it to manufacture carbohydrates (glucose). -----------> Glucose is changed to other organic compounds (fats, amino acids, proteins) ---------------> 1. Carbon compounds become part of the bodies of the animals that feed on the green plants. 2. Carbon compounds may be preserved in fossil fuels (coals, natural gas, oil)

the carbon cycle (picture from www.windows.ucar.edu)

RELEASE OF CARBON DIOXIDE INTO THE ENVIRONMENT

Carbon dioxide can be released into the environment through:

RESPIRATION
-When living organisms respire, carbon compounds (glucose) are broken down in their bodies and carbon dioxide is released into the environment.

COMBUSION
-When fossil fuels (coal, natural gas) are burnt or undergo combusion, carbon compounds preserved in the fossil fuels are broken down and carbon dioxide is released into environment.

DECAY
-When organisms die, their bodies decay or broken down into simple substances by decomposers.
-Carbon dioxide is one of the simple substance released into the environment during the process.
-Some of the simple substances are absorbed by the decomposers and become part of their body and carbon dioxide is released when they respire.

the carbon cycle (picture from wikipedia)

THE IMPORTANCE OF THE CARBON CYCLE

-It ensures that there's a continuous supply of carbon dioxide for plants to carry out photosynthesis. Photosynthesis converts energy from the sun into chemical energy in food, which other organisms can use to stay alive.

-Enables energy to flow through the ecosystem. Carbon compounds carry the trapped solar energy from organisms to organisms in the food chains of an ecosystem.

Thursday 25 December 2008!

HandWritten on; 13:18

WHAT HAPPENS TO MOST OF THE ENERGY IN THE ECOSYSTEM?

-As energy flows through the ecosystem, most of the energy is lost as heat energy to the environment.

-Energy may be lost in uneaten body parts

-through undigested matter egested by consumers

-through waste products excreted by consumers (urea)

picture from www.usoe.k12.ut.us

Tuesday 23 December 2008!

HandWritten on; 09:56

WHY ARE SHORT FOOD CHAINS BETTER?

-As energy is lost at each trophic level, less and less energy is available for the organism at the next level.
-A shorter food chain means more energy is available to the final consumer as less energy is lost to the environment.
-Thus a shorter food chain is more efficient than long food chains.

(picture from MSN)

Monday 22 December 2008!

HandWritten on; 09:14

WHAT ARE ECOLOGICAL PYRAMIDS?

-A graphical representation designed to show the biomass or productivity at each trophic level in a given ecosystem.

PYRAMID OF NUMBERS

-Used to compare the number of organisms present in each trophic level at a particular time.

PYRAMID OF BIOMASS

-Used to compare the mass of organisms present in each trophic level at a particular time.

-Constructed based on the dry mass of organisms in each trophic level at any one time. This is called the standing mass of organisms.

pyramid of biomass (picture from yahoo)

ENERGY OF ENERGY (productivity)

-Shows the total energy in the various trophic levels of a food chain

-The total energy content in each trophic level had to be determined over a period of time.

-Takes into consideration the rate of reproduction of organisms.

A lot of energy is lost to the environment as food is transferred from one trophic level to the next. It may be lost to the environment

as heat during respiration at every trophic level
in uneaten body parts
through undigested matter egested by consumers
through waste products excreted by consumers (urea)

-More and more energy is lost as we go down the food chain.

-The total energy is highest at the first trophic level and lowest at the last trophic level.

pyramid of energy (picture from MSN)

Variations in ecological pyramids

-Most ecological pyramids are pyramid-shaped but there are important exceptions

1. A pyramid of numbers may be upside down or inverted if:
-Organisms of one trophic level are parasitic on organisms of another trophic level.
-Many small organisms of one trophic level feed on a large organism of another trophic level

Tree------> Aphid------> Protozoa

2. The pyramid of biomass may be inverted of not pyramid-shaped.
-Based on the standing mass, not the rate of production of organisms.
-It's a disadvantage when considering organisms that reproduce rapidly.

Phytoplankton------> Zooplankton------> Small fish------> Large fish

Sunday 21 December 2008!

HandWritten on; 08:35

WHAT IS THE RELATIONSHIP BETWEEN A PREDATOR AND A PREY?

-A predator is an organism that kills and feeds on other organisms.

-A prey is an organism that are being eaten.

-An increase in the population size of the prey would lead to the increase in the number of predators as more food is available.

-This would cause an decrease in the population of prey which in turn results in a decrease in the predator as less food is available.

-The decrease in the number of predator allows an increase in the number of prey.

This cycle of predator-prey relationship repeats over time. The increase and decrease in the population of the predator follows the corresponding increase and decrease in the population of its prey.

Saturday 20 December 2008!

HandWritten on; 17:14

HOW DO ENERGY AND NUTRIENTS FLOW THROUGH AN ECOSYSTEM?

The living organisms in an ecosystem are made up of PRODUCERS CONSUMERS and DECOMPOSERS. Energy and nutrients are transferred from producers to consumers to decomposers through feeding.

PRODUCERS: -convert energy from the sun or light energy into chemical energy and store as food during

photosynthesis.

-ONLY organisms that can make their own food from inorganic raw materials.

-mainly green plants (including certain bacteria & algae)

-either directly or indirectly affect the lives of other organisms as they provide energy and oxygen.

CONSUMERS: -All animals

-obtain their energy by feeding on other organisms.

Primary consumers: -Herbivores

-feed directly on producers.

Secondary consumers: -Carnivores

-feed on herbivores (primary consumers)

Tertiary consumers: -Carnivores

-feed on other carnivores

DECOMPOSERS: -obtain energy by breaking down dead organisms faeces and excretory products.

-The materials locked up in the waste matter are released when they are broken down.

-Materials such as inorganic nutrients carbon and nitrogen compounds return to the physical environment and are used by the green plants.

FOOD CHAIN

-Path of food from a given final consumer back to a producer.

-Series of organisms through which energy is transferred in the form of food.

-Each stage in a food chain is known as a TROPHIC LEVEL.

ps. food chain do not have more than four trophic levels.

food chain (picture from pack152.net)

FOOD WEB

-interlinked from food chains

-may be two or more food chains in a food web

food web (picture from www.intandem.com)

Friday 19 December 2008!

HandWritten on; 17:32

ARE ORGANISMS INTERDEPENDENT?

YES! Organisms are NEVER completely independent. They depends on and is influendce by other organisms around it.

A change in one population affects the other population of the community.

Example: If the population of small crabs living in the mangrove community decreases, the population of mudskippers may also decrease as there's less food for them. The population of small worms and insects may also decrease as the mudskippers would tend to feed on them.

The biological balance or equilibrium is like a web --- breaking a single strand will affect the whole system.

Wednesday 17 December 2008!

HandWritten on; 17:02

THE PHYSICAL FACTORS

LIGHT INTENSITY
TEMPERATURE
AMOUNT OF WATER AVAILABLE
OXYGEN CONTENT
SALINITY
pH OF SOIL/WATER

The way in which animals and plants grow and carry out their different activities are a result of these abiotic factors. Organisms found in a region are usually adapted to the physical features of their environment.

EXAMPLES OF HOW ORGANISMS ADAPT TO THESE PHYSICAL FEATURES

Light intensity: -plants have hairs on the epidermis to screen off excessive light and heat.

Echeveria Leucotricha (MSN)

Temperature: -insulated by their 10cm blubber, their hide and their fur;they overheat at above 50F

polar bears (wikipedia)

Amount of water available: *Hydrophytes: -less rigid structure as water pressure support them
-flat leaves on surface plants and air sacs for flotation

Nymphaea Alba (water lily) (wikipedia)

*Xerophytes: -reduced permeability of epidermal layer
-succulent stems to store water

Euphorbia (wikipedia)
*Hydrophytes (aquatic plants): Plants adapted to living on or in aquatic environments.
*Xerophytes: Plants survive in ecosystem with little available water or moisture

Oxygen content: -mangrove plants have pneumatophores

-(snakehead) fish living in water of low oxygen content are usually air-breathers

Northern snakehead (wikipedia)

Salinity: -fresh water fish has scaly skins to keep water from entering their cells

-(amoeba) have contractile vacuoles to remove excess water that enters them by osmosis

Amoeba (www.sfu.ca)

pH of soil/water: -(freshwater fish) kidney reabsorbs salts and produces large amounts of dilute urine

!

HandWritten on; 16:36

WHAT COMPRISES ECOLOGY?

Ecology comprises of the following: HABITAT POPULATION COMMUNITY ECOSYSTEM

HABITAT: An ecological or environmental area that is inhabited by a particular animal or plant species.

POPULATION: Collection of inter-breeding organisms of a particular species living in a particular habitat.

COMMUNITY: All the population of organisms living and interacting with one another in a particular habitat.

ECOSYSTEM: Natural unit consisting of all plants, animals and micro-organisms in an area functioning together with all of the non-living physical factors of the environment.

These terms can be linked:

POPULATIONS------> COMMUNITIES------> ECOSYSTEMS------> BIOSPHERE*

*BIOSPHERE includes all parts of the Earth where life can be found.

picture from: wikipedia.