TS Inter 1st Year Botany Study Material Chapter 13 Ecological Adaptations, Succession and Ecological Services

Telangana TSBIE TS Inter 1st Year Botany Study Material 13th Lesson Ecological Adaptations, Succession and Ecological Services Textbook Questions and Answers.

TS Inter 1st Year Botany Study Material 13th Lesson Ecological Adaptations, Succession and Ecological Services

Very Short Answer Type Questions

Question 1.
Climax stage is achieved quickly in secondary succession as compared to primary succession. Why? [May ’14]
Answer:

1. Secondary succession begins in areas where natural communities have destroyed.
2. It is achieved quickly than primary succession, it occurs in abandoned farm lands burned or cut forests with some soil or sediment.

Question 2.
Among bryophytes, lichens and ferns which one is a pioneer species in a xeric succession?
Answer:

1. Lichens are pioneer species that growth on rocks in rocks in xeric succession.
2. They lead to soil formation through weathering of rocks by secreating acids.

Question 3.
Give any two examples of xerarch succession.
Answer:

1. Xerach succession takes place is dry areas and series progress from xeric to mesic conditions.
2. Formation of plant communities on dry rocks, on cooled and hardened lava from volcanoes.

Question 4.
Name the type of land plants that can tolerate the salinities of the sea. [Mar. ’14]
Answer:

1. Halophytes
2. Ex : Rhizophora

Question 5.
Define heliophytes and sciophytes. Name a plant from your locality that is either heliophyte or sciophyte.
Answer:

1. Plants which grow in direct sunlight are called heliophytes Ex : Tridax, grass plants
2. Plants which grow in shady places are called sciophytes Ex : Ferns, Mosses

Question 6.
Define population and community. [Mar. – 2019, May ’17, Mar. ’15 – T.S. ; Mar. ’13]
Answer:
Population :
It is a group of similar individuals belonging to the same species found in an area.

Community :
It is an assemblage of all the populations (belonging to different species) occurring in an area.

Question 7.
Define communities. Who classified plant communities into hydrophytes, mesophytes and xerophytes?
Answer:

1. Community : An assemblage of all populations (belonging to different species) occurring in an area is called community.
2. Warming classified plant communities into hydrophytes, mesopytes and xerophytes.

Question 8.
Hydrophytes show reduced Xylem. Why? [Mar. ’20, ’18, ’17, ’15]
Answer:
In hydrophytes, the absorption of water takes place through all over the surface of the plant body. So xylem is reduced.

Short Answer Type Questions

Question 1.
What are hydrophytes ? Briefly discuss the different kinds of hydrophytes with examples. [Mar. ’15 – T.S.]
Answer:
Plants growing in water or in very wet conditions are called hydrophytes. Hydrophytes are 5 types based on the way of developing in water.

1. Free floating hydrophytes :
They float freely on water. They have no contact with soil. Ex : Pistia, Eichhornia.

2. Rooted hydrophytes with floating leaves :
Roots of these plants are fixed in mud. Leaves have long petioles and float on water surface. Ex : Nelumbo, Nymphaea.

3. Submerged suspended hydrophytes :
These are not rooted. But they are completely submerged and suspended in water.
Ex : Hydrilla, Ceratophyllum,

4. Submerged rooted hydrophytes :
They are rooted at the bottom of the pond and remain submerged in water.
Ex : Vallisneria, Potamogeton

5. Amphibious plants :
They live partly in air and partly in water.
Ex : Ranunculus, Limnophila

Some plants growing around the water bodies are occasionally touched by water currents. They also survive in dry periods.
Ex : Cyperus, Typha.

Question 2.
Enumerate the morphological adaptations of hydrophytes. [Mar. – 2018]
Answer:
Morphological adaptations in hydrophytes :

1. Roots may be absent or poorty developed. In some plants submerged leaves compensate for roots.
2. Root caps are usually absent. However in some amphibious plants which grow in mud, roots are well developed with distinct root caps. In some plants, root caps are replaced by root pockets.
3. Roots, if present, are generally fibrous, adventitious, reduced in length, unbranched or poorly branched.
4. Stem is long, slender and flexible.
5. Leaves are thin, and either long and ribbon-shaped or long and linear or finely dissected. Floating leaves are large and flat with their upper surfaces coated with wax.

Question 3.
List out the anatomical adaptations of hydrophytes. [Mar. ’14, ’13]
Answer:
Anatomical Adaptations:

1. Cuticle is totally absent in the submerged parts of the plants. It may be present as very fine fiim on the surface of parts that are exposed to atmosphere.
2. Thin walled epidermal cells help in absorption and assimilation by having chloroplasts.
3. Stomata are totally absent in submerged forms or non-functional as in Potamogeton. The floating leaves of Nelumbo possess stomata only on the upper surface (epistomatous).
4. Mechanical tissues like collenchyma and sclerenchyma are absent, because the plants are not exposed to stress and strain.
5. Water is absorbed through all over the surface of plant body, so the xylem is poorly developed. But phloem is relatively better developed.
6. Aerenchyma present in all parts of all hydrophytes, provides buoyancy.

Question 4.
Write a brief account on classification of Xerophytes. [Mar. ’20, ’17; May. ’17, ’14]
Answer:
Plants growing in water deficient or physiologically dry habitats are called xerophytes.

Xerophytes are 3 types based on their morphology, physiology and life cycle pattern.

1. Ephemerals :
These are annuals which complete their life cycle within 6 – 8 weeks. They are also called drought evaders or drought escapers.
Eg : Tribulus.

2. Succulents :
These are drought avoiding plants. They absorb large amounts of water during rainy season and store in their parts in the form of mucilage. Those parts become fleshy and succulent. Stored water is used during dry periods.
Eg : (a) Root succulents – Ceiba parvifiora, Asparagus;
(b) Stem succulents – Opuntia;
(c) Leaf succulents – Bryophyllum, Aloe

3. Non succulents –
These are true xerophytes. These are perennial and withstand prolonged period of drought. Eg : Casuarina, Nerium.

Question 5.
Enumerate the morphological adaptations of xerophytes. [Mar. – 2019]
Answer:
Morphological adaptations in xerophytes :

1. Roots are long with extensive branching spread over wide areas.
2. Root hairs and root caps are very well developed.
3. Stems are stunted, woody, hard and covered with thick bark.
4. Stems are usually covered by hairs and or waxy coatings.
5. Leaves are very much reduced, small, scale like and sometimes modified into spines to reduce the rate of transpiration.

Question 6.
Give in detail the anatomical adaptations shown by xerophytes. [Mar. ’15 – A.P]
Answer:
Anatomical adaptations :

1. Epidermis is covered by thick cuticle to reduce transpiration.
2. Epidermal cells are thick walled and may have silica crystals.
3. Multilayered (multiple) epidermis is present as leaves of Nerium.
4. Leaves and stem of Calotropis consists of waxy coating.
5. Stomata are generally confined to lower epidermis of leaves (hypostomatous) and present in pits (sunken stomata) lined with hairs. Eg : Nerium.
6. Mesophyll in leaves is very well differentiated into palisade and spongy paren¬chyma.
7. Mechanical tissues are very well developed.
8. Vascular tissues are very well developed.

Question 7.
Define Plant succession. Differentiate primary and secondary successions.
Answer:
The gradual change in structure and composition of all communities constantly in response to the changing environment till it reaches equilibrium is called plant succession.

Primary succession	Secondary succession
1. Succession that starts where no living organisms ever existed is called Primary succession. Ex : Bare rocks	1. Succession that starts in the areas where somehow all living organisms that existed are lost is called secondary succession. Ex: Abandoned farmlands, burned forests
2. It occurs in biologically sterile area.	2. It occurs in biologically fertile area.
3. It takes long time to reach the climax stage.	3. It occurs faster than primary succession because of the presence of soil.

Question 8.
Define ecosystem/ecological services. Explain in brief with regard to pollination.
Answer:

1. Natural ecosystem performs fundamental life support services called ecosystem services or ecological services.
2. Transfer of pollen grain from anther to stigma is called pollination.
3. Most flowering plants require help from pollinators to produce fruits and seeds. So Pollinators play a significant role in the production of more food crops in the world.
4. The most important pollinators for agricultural purpose is the honey bee.
5. Predicting the effects of the loss of a particular pollinator is extremely difficult, but it is important to remember that no species exists in isolation.
6. Each is part of an ecological web, and as we lose more and more pieces of that web, the remaining structure must eventually collapse.
7. If pollination services are lost due to the loss of some species, then those remaining are unable to compensate the loss.
8. Decline in pollinator activity disturbs the entire ecological system.

Question 9.
Write about the measures to be taken to sustain ecological functions.
Answer:

1. Choose products produced with methods that conserve resources, minimize waste and reduce or eliminate environmental damage.
2. Prefer products made with methods that reduce or eliminate the use of pesticides and artificial fertilizers.
3. Reduce consumption and waste production.
4. Support usage of renewable energy alternatives.
5. Use public transit, cycle or walk to conserve natural resources and to reduce pollution and enjoy the health benefits.
6. Participate in developing community garden and tree plantation programmes.
7. Avoid the usage of pesticides and follow methods of natural pest control.
8. Use native plants in the garden and provide habitat for wild life.

Question 10.
What measures do you suggest to protect the pollinators?
Answer:

1. Creating own pollinator – frendly garden using a wide variety of native flowering plants. Encourage the planting of native flowers in open spaces and outside public buildings.
2. Reducing the level of pesticides used in and around your home.
3. Encouraging local clubs or school groups to build artificial habitats such as butterfly gardens, bee boards and bee boxes.
4. Supporting agriculture enterprises with pollinator-friendly practices such as forms that avoid or minimize pesticide use.
5. Encouraging government agencies to take into account the full economic benefits of wild pollinators when formulating policies for agriculture and other land uses.
6. Stress the need to develop techniques for cultivating native pollinator species for crop pollination.

Long Answer Type Questions

Question 1.
Give an account of ecosystem services with reference to carbon fixation and oxygen release.
Answer:
Ecosystem Service – Carbon Fixation :
Trees are essential to all living organisms. Exchange of CO₂ and O₂ is done by photosynthesis. Forests provide a vast bank for CO₂ and a huge amount of CO₂ is deposited in its timber. This cuts down the CO₂ concentration in atmosphere and plays an essential role in maintaining a dynamic balance between CO₂ and O₂ in atmosphere. So CO₂ fixation has an obvious indirect economic value that can be estimated by taking account alternative methods of fixing CO₂.

According to photosynthesis equation, to produce 180 g glucose and 193 g O₂, plant will absorb 264 g CO₂ and 108 gm water and consume 677.2 k.cal of solar energy. Then 180 g glucose can be transformed to 162 g polysaccharide inside the plant. Therefore, whenever plant produces 162 gm of dry organic water, 264 g CO₂ will be fixed, i.e., production of every 1 gm dry organic matter can fix 1.63 g CO₂.

The economic value of CO₂ fixation can be estimated by the total fixed CO₂ amount multiplied by a standard opportunity cost for per unit CO₂ fixation.

Natural ecosystems may have helped to stabilize climate and prevent overheating of the Earth by removing more of the greenhouse gas, CO₂ from the atmosphere. Ecosystem service-Oxygen release : Plants take CO₂ and give CL during photosynthesis. The amount of O₂ produced by a tree depends upon its age, health and also on the tree’s surroundings. According to Research findings, “a mature leafy tree produces as much as oxygen in a season as 10 people inhale in a year”.

Another quotes “A single mature tree can absorb CO₂ at a rate of 48 lbs / year and release enough oxygen back into the atmosphere to support 2 human beings.”

Other quote “One acre of trees annually consumes the amount of carbon dioxide equivalent to that produced by driving an average car for 26000 miles. That same acre of trees also produces O₂ for 18 people to breathe for a year.”

Submerged water plants release O₂ and enrich dissolved oxygen in water.

Plants and Planktons are described as “the lungs of the world”.

Micro-organisms also produce O₂ directly or indirectly. Cyanobacteria produce O₂ directly; some bacteria indirectly.

For example, the degradation of organic compounds by bacteria can make the compounds capable of being used as a food source by another organism. This subsequent utilization can both consume and produce oxygen at various stages of the digestive process.

Intext Question Answers

Question 1.
Categorise the following plants into hydrophytes, halophytes, mesophytes and xerophytes and give reasons.
a) Salvinia b) Opuntia C) Rhizophora d) Mangifera
Answer:
a) Salvinia is a hydrophyte, it grows on the surface of water.
b) Opuntia is a xerophyte, grows in dry areas.
c) Rhizophora is a halophyte, it tolerates the salinities of the sea.
d) Mangifera is a mesophyte, it grows in habitats where water availability is normal.

Question 2.
In a pond, we see plants which are free-floating ; rooted-submerged ; rooted emergent ; rooted with floating leaves. Write the type of plants against each of them.
Answer:

Plant name	Type
a) Hydrilla	Submerged suspended hydrophyte
b) Typha	Amphibious plant
c) Nymphaea	Rooted with floating leaves
d) Lemna	Free floating hydrophytes
e) Vallisnaria	Submerged rooted hydrophyte

Question 3.
Undertake the following a part of learning process :
a) Identify and assess ecological services found in your area.
b) Think of measures or means to sustain such ecological services.
c) Observe the type of plants or crops grown in your area.
d) Enumerate ecological services of your area.
e) Find out the ecological goods of natural forests commonly used in your area.
f) Observe the biotic agents of pollination for ornamental flowering plants and or agricultural crops in your locality.
Answer:
a) Ecological services :

1. Purification of air and water
2. Decomposition of water
3. Detoxification of water

b) Measures to sustain Ecological services :

1. Reduce consumption and waste production
2. Avoid the usage of pesticides

c) Crops grown in our area :

1. Paddy
2. Maize
3. Vegetables
4. Blackgram

d) Ecological services:

1. Purification of air and water
2. Decomposition of wastes

e) Ecological goods:

1. Clean air
2. Fresh air
3. Fibre
4. Timber
5. Medicines

f) Biotic agents of pollination :

1. Insects
2. Birds
3. Animals like bats, snails, etc.