plant kingdom class 11 notes
1. WHAT ARE THE DIFFICULTIES THAT YOU WOULD FACE IN CLASSIFICATION OF ANIMALS , IF COMMON FUNDAMENTAL FEAUTURES ARE NOT TAKEN INTO ACCOUNT?
- These are numerous animal species which show great variety of life. The various common fundamental characters are taken into account for the classification of those animals. If this has not been done. It is not possible to deal with every living form separately at individual level. Therefore, a classification has to be based on the common fundamental characters to study the diversity properly.
- The inter relationship among different animals will not be traceable.
- The picture of all animals at a glance will not be projected.
- The development of other animal species will not be made.
2. IF YOU ARE GIVEN A SPECIMEN, WHAT ARE THE STEPS THAT YOU WOULD FOLLOW TO CLASSIFY IT ?
Various steps considered to classify specimen are :
- made of nutrition – it can be autotrophic holozoic, saprophytic or paraditic.
- complexity of blood structure –whether the specimen is unicellular or multicellular.
- presence or absence of membrane bound organelles.
- Body symmetry, i.e the plant by which organism can be divided into two equal halves.
- Presence or absence of coelom, it can be acoelomates , pseudocoelomates , eucoelomates.
- Phylogenetic relationship
3. HOW USEFUL IS THE STUDY OF THE NATURE OF BODY CAVITY AND COELON IN THE CLASSIFICATION OF ANIMALS?
Coelom is a fluid filled space between the body wall and digestive tract. The presence or absence of body cavity or coelom plays a very important role in the classification of animals. Animals that possess a fluid filled cavity between body wall and digestive tract are known as coelomates. Annelids, mollusks, arthropods, echinodermates, and chordates are examples of coelomates. On the other hand, the animals in which the body cavity is not lined by mesoderm are known as pseudocoelomates. In such animals, mesoderm is scattered in between ectoderm and endoderm. Aschelminthes is an example of pseudocoelomates. In certain animals, the body cavity is absent.
They are known as acoelomates. An example of acoelomates is platyhelminthes.
4. DISTINGUISH BETWEEN INTRACELLULAR AND EXTRACELLULAR DIGESTION ?
- intracellular digestion: Intracellular digestion is a form of digestion which takes place within the cytoplasm of the organism. Intracellular digestion takes place in animals without a digestive tract, in which food items are brought into the cell for digestion.
- extracellular digestion: Extracellular digestion is a process in which animals feed by secreting enzymes through the cell membrane onto the food. The enzymes break the food into molecules small enough to be taken pass through the cell membrane into the cell. These nutrients are transferred into the blood or other body fluids and distributed to the rest of the body.
5. WHAT IS THE DIFFERENCE BETWEEN DIRECT AND INDIRECT DEVELOPMENT ?
DIRECT DEVELOPMENT :
- It Is a type of development in which an embryo develops into a nature individual without involving a larval stage.
- Metamorphosis is absent
- It occurs in fishes, reptiles, birds and mammals
INDIRECT DEVELOPMENT :
- it is a type of development that involves a sexually immature large stage, having different food requirements than adults.
- Metamorphosis involving development of larva to a sexually mature adult is present.
- It occurs in most of the invertebrates and amphibians.
6. What are the peculiar features that you find in parasitic platyhelinthes?
- They have dorso-ventraly flattened body, hence are called flatworms.
- Hooks and suckers are present, which absorb nutrients from the host directly throught their body surface.
- Flame cells are present, which helps in osmoregulation and excretion.
- Some members like Plamria possess high regeneration capacity.
- Example: Tapeworm, Liver fluke etc.
7. What are the reasons that you can think of for the arthropods to constitue the largest group of the animal kingdom?
Arthropods are most successful animals and constitute the largest group of the animal kingdom. over two-thirds of all named species on earth are arthropods. They range in distribution from deep sea to mountain peaks.
The reasons for the success of arthropods are-
- Hard chitinous exoskeleton- Thick, tough, non-living chitinous cuticle forms the exoskeleton which protects the organism from predators, help to withstand temperature upto 100°C or more and prevents water loss.
- Jointed appendages- Jointed legs and wings that allow more mobility on land and air
- Ability to reproduce and metamorphose- They have ability to reproduce very fast and less time is needed for young ones to hatch from their eggs. Due to metamorphosis, there is less competition among larval and adult forms for food.
8. Water vascular system is the characteristics of which group of the following :
(a) porifera
(b)ctenophora
(c)echinodermata
(d) chordata
Water vascular system is a characteristic feature of the phylum, Echinodermata. It consists of an array of radiating channels, tube feet, and madreporite. The water vascular system helps in locomotion, food capturing, and respiration.
9. “All vertebrates are chordates but not chordates are not vertebrates”. Justify the statement.
The characteristic features of the phylum chordata include the presence of a notothorad and paired pharyngealgill slits. In sub–phylum vertebrata, the notochord present in embryos gets replaced by a cartilaginous or bony vertebral column in adults.but in cephelochordates , notochord perisits throughout life as such and in urochordates , the notochord is present only in larval stages all absent in adults thus, it can be said that all vertebrates are chordates but all chordates are not vertebrates.
10. How important is the presence of air blades in pisces ?
Air bladder in Pisces regulates buoyancy and helps in floating in the water. It prevents them from sinking
Air bladder is present in members of the class Osteichthyes.
Animals of the class Chondrichthyes do not have air bladder and in the absence of air bladder, the animals have to,swim constantly to avoid sinking.
11. What are the modifications that are observed in birds that help them fly ?
- streamlined body for rapid and smooth movement
- covering of fathers for insulation
- forelimbs modified into wings and hind limbs used for walking,perching and swimming
- presence of pneumatic bones to reduse weight
- presence of additional air sacs to supplement respiration.
12. Could the number of eggs of young ones produced by an oviparous and viviparous mother be equal? Why?
In oviparous animals, young ones develop outside the mother body and are prone to harsh climatic conditions and predators. To compensate, oviparous females lay a number of eggs each time. In viviparous animals, young ones are developed inside the female body and one or a few eggs are produced per cycle. So, number of eggs produced by oviparous and viviparous animals can not be equal.
13. Segmentation in the body is first observed in which of the following ?
(a) platyhminthes
(b) aschelminthes
(c) annelida
(d) arthrpoda
The body segmentation first appeared in the phylum, Annelida (annulus meaning little ring)
14. Prepare a list of some animals that are found parasitic on human beings ?
- Taenia solium (Tape worm ) Platyhelminthes.
- Fasciola hepatica (blood worm ) Platyhelminthes
- Ascaris lumbricoides ( Round worm ) Ascheliminthes
- Wuchereria bancrofti ( Final worm ) Aschelminthes
- Ancyclostoma ( Hook worm ) Aschelminthes
