Question

1. What did the production of oxygen by photosynthetic organisms form in the atmosphere?

2. Explain what a plant is. (What makes plants different from other organisms?

a. What are carnivorous plants and where do they grow?

3. Explain the two challenges plants faced with moving onto land.

4. Explain the two physiological plant adaptations which allowed for plant life on land.

5. What are the key features that make the four categories of plants different?Non-vascular:Vascular seedless: Gymnosperms:Angiosperms: a. List the evolutionary order of plant traits.

6. Angiosperms (flowering plants):

a. What are the female reproductive structures? What are the male sex structures?

b. What are the four strategies for attracting pollinators?

c. List the 4 mechanisms of seed dispersal and examples of each.

Answer 1

1. Production of oxygen by plants during photosynthesis leads to the formation of ozone in atmosphere.

2. Plants are autotrophic organisms and are also called as producers. They undertake the process of photosynthesis to synthesise sugar in the presence of Sunlight and chlorophyll molecules. Because of this they can fulfill their nutritional requirement by their own and therefore are not dependent on other organisms.

3. Carnivorous plants are those which cannot undertake the process of photosynthesis and therefore depend upon other organisms for energy requirement. These parts are also called as insectivorous plants because they feed upon insects. Examples of this category of plants include pitcher plant and Venus fly trap. These plants grow in areas where there is no sunlight and poor quality of soil with respect to nutrient and composition.

4. Plants are able to grow on land because of the presence of vascular tissue. Bryophytes do not contain vascular tissue and therefore cannot grow on land and require water for growth. Pteridophytes which contain primitive type of conducting tissue and conducting cells can grow in the absence of water on land. Gymnosperm contain primitive type of conducting tissue and some of the gymnosperms contain tracheids and vessels. Angiosperm contain a well developed vascular tissue in the form of xylem and phloem. Xylem is responsible for the transportation of water from Roots to the aerial parts of the plant and phloem is responsible for the transportation of Sugars from leaves to the other parts of the plant.

Another type of adaptation due to which plants can grow on land is the presence of well defined root system along with root hair. Bryophytes and pteridophytes do not have a well defined root system because they have water in their immediate environment. But gymnosperms and angiosperms absorb water from underground and sometimes the water may be very deep into the ground and therefore a well defined root system is required.

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