What are the major divisions in the Plantae? What is the basis for these divisions?
The kingdom Plantae is divided into five main divisions: Thallophyta, Bryophyta, Pteridophyta, Gymnosperms, and Angiosperms.
The classification depends on the following criteria:
• Differentiated / Undifferentiated plant body
• Presence / absence of vascular tissues
• With/without seeds
• Naked seeds/ seeds inside fruits
(i) Thallophyta : these are simple , thalloid and undifferentiated body parts. They do not have roots, stems and leaves.
(ii) Bryophyta : their plant body is more differentiated and has root ,stem and leaf-like body parts. They do not have vascular tissue.
(iii) Pteridophyta : they have true root, stem and leaf. They possess well differentiated vascular tissue.
(iv) Gymnosperm : the plants in which ovules are not enclosed by any ovary wall i.e naked - seeded plants.
(v) Angiosperm : seeds are enclosed in fruits.
How do poriferan animals differ from coelenterate animals?
Explain the basis for grouping organisms into five kingdoms.
Explain how animals in Vertebrata are classified into further subgroups.
Which organisms are called primitive and how are they different from the so-called advanced organisms?
How do gymnosperms and Angiosperms differ from each other?
Give three examples of the range of variations that you see in life-forms around you.
How do annelid animals differ from arthropods?
Which do you think is a more basic characteristic for classifying organisms?
(a) the place where they live.
(b) the kind of cells they are made of. Why?
What are the differences between amphibians and reptiles?
In the hierarchy of classification, which grouping will have the smallest number of organisms with a maximum of characteristics in common and which will have the largest number of organisms?
Which of the following has more inertia: (a) a rubber ball and a stone of the same size? (b) a bicycle and a train? (c) a five-rupees coin and a one-rupee coin?
State the universal law of gravitation.
Which of the following are matter?
Chair, air, love, smell, hate, almonds, thought, cold, cold-drink, smell of perfume.
A force of 7 N acts on an object. The displacement is, say 8 m, in the direction of the force (Fig. 11.3). Let us take it that the force acts on the object through the displacement. What is the work done in this case?
What is meant by a pure substance?
How does the sound produced by a vibrating object in a medium reach your ear?
In a reaction, 5.3 g of sodium carbonate reacted with 6 g of ethanoic acid. The products were 2.2 g of carbon dioxide, 0.9 g water and 8.2 g of sodium observations are in agreement with the law of conservation of mass.
sodium carbonate + ethanoic acid → sodium ethanoate + carbon dioxide + water
What are canal rays?
State any two conditions essential for good health.
How is our atmosphere different from the atmospheres on Venus and Mars?
Complete the table:
Why do you fall in the forward direction when a moving bus brakes to a stop and fall backwards when it accelerates from rest?
Why are we normally advised to take bland and nourishing food when we are sick?
Make a comparison and write down ways in which plant cells are different from animal cells.
Why is sound wave called a longitudinal wave?
Which of the following conditions will give the most benefits? Why?
(a) Farmers use high-quality seeds, do not adopt irrigation or use fertilizers.
(b) Farmers use ordinary seeds, adopt irrigation and use fertilizer.
(c) Farmers use quality seeds, adopt irrigation, use fertilizer and use crop protection measures.
Helium atom has an atomic mass of 4 u and two protons in its nucleus. How many neutrons does it have?
How are sol, solution and suspension different from each other?
Draw a labelled diagram of a neuron.
How does an Amoeba obtain its food?