BIOLOGY 2 Marks Questions

3. 4

1. Parotids.

3. Convergent evolution.

4. Linnaeus.

1. Echinoidea.

1. Two

Explanation:

All vertebrates have a muscular chambered heart. 

Fishes have a two chambered heart with a single atrium and a ventricle. 

In fishes, the heart pumps out deoxygenated blood which is oxygenated by the gills and supplied to the body parts from where deoxygenated blood is returned to the heart (single circulation).

2. Forelimbs are modified for flight in Bats.

2. Flame cells.

2. Nematocysts.

3. Pseudocoelom.

1. A is true but R is false.

3. Benthos/ sedentary.

3. Fasciola is a pseudocoelomate animal.

Explanation:

The statement, Fasciola is a pseudocoelomate animals, is incorrect as it does not possess body cavity hence, it is an acoelomate. Mesoglea is an undifferentiated layer and is a characteristic of diploblastic and triploblastic animals present along with ectoderm and endoderm. Symmetry in which the body can be divided into two equal identical halves from any plane passing through the central axis. as shown by Asterias, is called radial symmetry Taenia is a triploblastic animal, it possesses three germinal layers, i.e., ectoderm, endoderm and mesoderm. 

1. Spicules.

4. Forelimb.

1. Excretory organs of insects.

4. Male shark-Claspers borne on pelvic fins.

1. Ascon type.

1. Syrinx.

2. Metamerism.

Explanation:

Metamerism is true segmentation where external divisions correspond to internal divisions. The body is divided both externally and internally into number of segments (100-120) called metameres. E.g., In earthworm, genital papillae are present in 17lh and 19th segments and nephridipores are scattered all over body surface except first two. Metagenesis is alternation of two life forms in an organism. Metamorphosis is phenomenon of passing through different juvenile stages before attaining adult form. Segmentation is division of- body into different segments and in some organisms, only external divisions are seen as head, thorax and abdomen.

1. Flame cells.

4. Posterior sucker in Hirudinaria.

3. Double circulation.

1. Scales on their hind limbs.

3. Python.

Explanation:

Python is a large and non-poisonous snake. It kills its prey by coiling around and crushing and swallowing the prey.

1. Platypus lays eggs.

3. Crocodilus – 4-chambered heart.

Explanation:

Hippocampus (seahorse) belongs to class Osteichthyes. It has 2-chambered heart (one auricle and one ventricle). Rana (frog) belongs to class Amphibia. It has a 3-chambered heart (two auricles and one ventricle). Crocodilus (crocodile) belongs to class reptilia. It is an exception in reptiles. Pavo (peacock) belongs to class aves. It has 4-chambered heart.

1. (i), (iii) and (iv).

3. Mollusca bogo.

4. Fangs

Explanation:

Fangs are long, pointed, and grooved teeth connected to the venom - producing sac in snakes.

As these are connected to the venom-producing sac, these can inject poison into the enemy, when the snake bites.

4. Pectoral girdle/ clavicles.

3. Sea-cucumber.

2. Tadpole/ fish.

3. Rabbit and whale

Explanation:

Viviparity means the development of the embryo inside the body of the mother, eventually leading to live birth, as opposed to laying eggs.

Mammals are best examples of viviparity.

Rabbit and whale are mammals, so they show viviparity.

2. Hydra and sponges.

1. Homeothermy.

4. Nematoda.

1. Absence of body cavity.

1. In cockroaches and prawns excretion of waste material occurs through malpighian tubules.

Explanation:

In cockroaches excretion takes place by Malpighian tubules while in prawns it takes place by green glands.

1. Fishes were amphibious in the past.

2. Pseudocoelomates.

​​​​​​​Explanation:

Acoelomates are characterised by absence of coelom or body cavity while coelomates are those organisms in which body cavity arises as a cavity in embryonic mesoderm and mesoderm lines the coelom. In pseudocoelomates body cavity is derived from blastocoel of embryo but is not lined with mesoderm.

3. Malpighian tubules.

4. Pseudocoelom.

2. Radial.

3. Archaeopteryx.

3. Digestive tract.

1. Hydra.

2. Fish

Explanation:

Fishes have two chambered heart - one auricle and one ventricle. Auricle is responsible for taking in blood from body and ventricle pumps out the blood that has entered the heart through gills and give fresh oxygen to the blood. 

4. Three pairs of ganglia.

4. order.

2. Platypus.

4. Butterfly, frog and mosquito.

4. Moist skin.

2. Australia.

2. Platyhelminthes and Annelida.

2. Pseudocoelom.

1. Ammonotelic.

3. Shark.

3. Cuttle fish.

2. Postanal tail.

1. Asteriodea.

3. Post-anal tail.

1. Tapeworm.

2. 3

2. Non-collapsible walls.

2. Radial symmetry.

2. Two pairs of antenna.

3. A-i, B-iii, C-v, D-iv, E-ii

1. Lampreys and hag fishes.

3. Vertebrates.

2. Ornithorhynchus.

1. Schistosoma.

3. Typhus.

1. Tuataras.

4. Flying fish.

4. Frog.

2. Muscular diaphragm between thorax and abdomen.

4. Mosquito larvae in permanent waters.

1. Presence of notochord.

3. Pheretima.

2. Echinodermata.

3. Monkey, Chimpanzee, Man.

Explanation:

In option 'c' all organisms belong to mammalia. Option 'a' has dogfish and starfish as odd ments out. Option 'b'has animals from three different taxa. Option 'd' also has animals from three different taxa.

2. Crocodiles, Birds, Mammals.

Explanation:

Amphibians have three-chambered heart, while reptiles have incomplete four-chambered heart (except crocodiles). Crocodiles, birds and mammals have complete, four-chambered heart.

1. Osmoregulations.

1. Aves.

3. Pheretima (Earthworm) - Aschelminthes.

Expalnation:

Pheretima (earthworm) - Aschelminthes is not a matching pair because Pheretima belongs to phylum Annelida and not to Aschelminthes.

1. Platyhelminthes.

2. Metanephros.

3. Musca.

2. Aschelminthes : Ancylostoma, Enterobius, Tubifex.

2. Spicules.

2. 4 pair.

2. Contaminated cooked measly pork.

2. Aschelminthes.

Explanation:

Aschelminthes is a pseudocoelomate.

3. i-D, ii-A, iii-B, and iv-C

4. Sea anemone.

3. Cyprinus caprio.

2. Interstitial cells.

Explanation:

Interstitial cells can differentiate to perform different functions. Choanocytes is the characteristics cells of porifera. Gastrodermal cells and Nematocytes are found in Hydra.

3. Have gill slits at some stage.

3. Coelenterata and Echinodermata.

2. Endothermic.

1. Anal styles in male.

2. True placentation.

4. Snake.

4. Mature proglottids contain both male and female organs

3. Ecdysone.

2. Contractile vacuole.

2. Starfish.

4. Mesoderm on both sides.

3. Sand fly.

3. Rostellar hooks are absent.

3. Echinodermata.

1. Crocodile.

1. Internal fertilization, are oviparous and eggs are covered with calcareous shell.

2. Keel of sternum.

2. Chameleon and Turtle.

Explanation:

Chameleon and turtle belong to class-Reptilia and possess dry and non-glandular skin with scales, Frog, pigeon and tiger possess modifications in their skin according to adaptations in their respective habitats. 

1. Platypus.

Explanation:

Platypus is a primitive mammal which shows many characters of their reptilian descent, such as ovaparity, i.e., these lay eggs. Rest all three animals, i.e., flying fox, elephant and whale are viviparous mammals and giving birth to young ones. 

2. Antarctica.

3. Aschelminthes (round worms).

2. Both.

2. Chordata.

4. Mammal

Explanation:

Mammals do not lay eggs but reproduce and develop the embryo within their body before giving birth.

They are known as viviparous.

4. Cephalopoda.

3. Ten pairs of cranial nerves.

3. Dorsal surface.

2. Muscular diaphragm.

1. Oncosphere.

2. Rhabditiform.

3. Flightless birds.

4. Warm blooded.

Explanation:

Both birds and mammals are homoiotherms (warm blooded) i.e., they have ability to maintain constant body temperature inspite of changes in ambient conditions.

3. Cartilaginous.

1. Annelida.

3. Ten pairs of cranial nerves.

2. Sponges.

1. Rana tigrina.

2. Super class pisces.

4. Lampreys and hag fishes.

2. Gill cover/ operculum

Explanation:

Cartilaginous fishes have a cartilaginous exoskeleton and belong to class Chondrichthyes.

Example: Sharks. 

Their characteristics are:

Broad paired fins and caudal fin.

Gills are not covered by an operculum (gill cover).

Exoskeleton contains placoid scales which are dermal in origin.

Mouth is ventral.

Cartilaginous fishes do not contain gill cover/ operculum.

1. Presence of skull.

2. Jointed legs and chitinous exoskeleton.

2. Lizards and Sparrow.

2. Presence of mammary glands.

4. Ten pairs of cranial nerves.

4. Chondrichthyes : possess cartilaginous endoskeleton.

2. Dorsal, hollow central nervous system.

2. Conserve water.

4. Axial skeletal rod of notochord.

4. Wuchereria—filariasis.

2. Sitting posture.

3. Flower sap.

4. Red with haemoglobin in plasma.

2. Scyphozoa.

1. Pila sp.

2. They make the soil porous, leave their castings and take organic debris in the soil.

1. Useful.

4. Kangaroo, hedgehog, dolphin, loris.

3. Reptiles.

2. Mesozoic.

4. Gambusia.

3. Syrinx.