BT101 Final Term Current Solved Paper 2017

Honeybees, caterpillars, butterflies, and other insects feed on a male flower’s nectar, picking up pollen in the process, and then pollinating female flowers when they feed on them.

Red tide:

The harmful and toxic blooms of red Dinoflagellates causes the colour of sea water to become red. Red Dinoflagellates (Example: Gonyaulax) undergo such rapid multiplication that they make the sea appear red

Characters of Phycomycetes:

The mycelium is aseptate and coenocytic. Asexual reproduction takes place by zoospores (motile) or by aplanospores (nonmotile). These spores are endogenously produced in sporangium.

Examples of Phycomycetes:

Mucor Rhizopus (the bread mould) Albugo (the parasitic fungi on mustard).

Eutrophication Too much nutrients causes harmful algal blooms (HABs) which are extremely toxic to living creatures (fish, shellfish, birds and mammals) It decreases the oxygen content rapidly

Aquatic biomes: Aquatic biomes are further classified into, Saltwater biome Freshwater biome

Terrestrial biomes: Tundra biome Desert biome Grassland biome Forest biome

Species whose populations have expanded dramatically and outcompete or displace native species, potentially threatening the structure and function of intact ecosystems. Non native species that have a potential to cause economic or environmental harm to humans are termed as invasive species

The Nile perch introduced into Lake Victoria in east Africa led eventually to the extinction of an ecologically unique assemblage of more than 200 species of cichlid fish in the lake The recent illegal introduction of the African catfish Clarias gariepinus for aquaculture purposes is posing a threat to the indigenous catfishes in our rivers.

Global warming:

The average temperature of earth surface is increasing day by day due to increase in concentration of greenhouse gases in the atmosphere. Human activities are main cause of it. The earth is gradually heating up due to rise in temperature. This phenomenon is called Global warming. It is causing serious problems to the health of plants and animals and also the surrounding environment.

Causes of Global warming:

Burning of fossil fuels Volcanic eruption Industrial effluents Deforestation Transportation Power plants Effects of Global warming Rise in temperature Rise in Sea Level Climate change Extinction Droughts Loss of biodiversity

1. Protozoans:-

All protozoans are heterotrophs and live as predators or parasites. Amoeboid protozoans Flagellated protozoans Ciliated protozoans Sporozoans

Amoeboid protozoans: These organisms live in fresh water, sea water or moist soil. They move and capture their prey by putting out pseudopodia (false feet) as in Amoeba. Marine forms have silica shells on their surface. Some of them such as Entamoeba are parasites.

Flagellated protozoans: Freeliving or parasitic. They have flagella. The parasitic forms cause diastases such as sleeping sickness.

Ciliated protozoans: Aquatic and movement by cilia. A cavity (gullet)opens to outside of the cell surface. The coordinated movement of rows of cilia causes the water loaded with food to be driven into the gullet. Example: Paramoecium.

Sporozoanes: This includes diverse organisms that have an infectious sporelike stage in their life cycle. The most notorious is Plasmodium (malarial parasite) which causes malaria, a disease which has a staggering effect on human population.

Growth forms of Lichens :

Crustose :A type of lichen that form a flat crust on the substratum and firmly attached to substratum.

Foliose: This type of lichens has flat leaf like structures and are attached to substratum by thread like structures .

Fruticose: This type of lichens have erect filamentous like outgrowths and possess vertical pattern of growth.

Benefits of Lichens Bioindicators Ecosystem sustainability Medicines Animal food Dye for clothes

Common form of symbiosis are Commensalism , Mutualism.

Euglenoids: have a protein rich layer called pellicle which makes their body flexible.

Certain marine algae produce large amounts of volatile DMS (dimethyl sulfide). In the atmosphere, DMS is converted to sulfur dioxide, some of which in turn is converted to sulfur trioxide gas and to tiny droplets of sulfuric acid (H2SO4 ).

Neurospora is used extensively in biochemical and genetic work. Many members like morels and truffles are edible and are considered delicacies. Importance of biodiversity    Biodiversity performs important biological services.

1. Regulation of Climate
2. Soil formation and protection
3. Water resources protection
4. Education and scientific value
5. Recreation and ecotourism
6. Pollution breakdown and absorption
7. Economic value

2. Lentic water bodies

Standing bodies of freshwater that supports variety of life. Wind action is very vital in these water bodies because it increases the content of dissolve oxygen that is necessary for the aquatic life in these water bodies.

Effects of deforestation: Increase in carbon dioxide concentration in the atmosphere. Habitat destruction. Climate change Loss of biodiversity. Hydrologic cycle disturbances. Soil erosion. Desertification.

3. Steps in nitrogen cycle

Fixation:

Two natural processes convert or fix N2 into compounds useful as nutrients for plants and animals. Electrical discharges, or lightning, taking place in the atmosphere. Nitrogen fixation by nitrogen fixing bacteria

Nitrification:

Specialized soil bacteria convert most of the Ammonia (NH3) and Ammonium ions (NH4+) in soil to nitrate ions (NO3 ) which are easily taken up by the roots of plants.

Assimilation:

The plants then absorb nitrates from the soil into their roots to produce various amino acids, proteins, nucleic acids, and vitamins.

Ammonification:

When a plant or animal dies, specialized decomposer bacteria convert this detritus into simpler nitrogencontaining inorganic compounds such as Ammonia (NH3) and watersoluble salts containing Ammonium ions (NH4+)