The elicitors are recognized by receptor-like molecules present in resistant plants. This recognition initiates several biochemical reactions such as

1. Phytoalexin biosynthesis

2. Cell wall reinforcement

3. Release of hydrolytic enzymes

4. Rapid cell death

Which of the following is/are correct?

TLS Online TPP Program

#Question id: 12248

#Unit 10. Ecological Principles

The graphs below show the survivorship and fecundity curves for two congeneric species, X and  Y, that are found in different habitats. Of the two species, Y is more likely to

TLS Online TPP Program

#Question id: 12249

#Unit 10. Ecological Principles

In Batesian mimicry, a harmless species mimics a harmful or toxic model species. Increasing the relative abundance of the mimic will:

TLS Online TPP Program

#Question id: 12250

#Unit 10. Ecological Principles

Two islands, P and Q, are similar in habitat and other features. They are 100 and 200 km2 in size respectively, but have the same number of species. Which of the following statements can independently explain this observation?

(i)    P is closer to the mainland than Q

(ii)   P is further away from the mainland than Q

(iii)  P has higher speciation rates than Q

(iv) P has lower speciation rates than Q

TLS Online TPP Program

#Question id: 12251

#Unit 10. Ecological Principles

A plant produces flowers that are open through the day and the night. An experimenter places pollen on the stigmas of freshly opened flowers and covers them after pollination to prevent natural pollinators from having access to the flowers. When experimental pollination was carried out during the day, 40% of the flowers yielded fruit. When experimental pollination was carried out during the night, 80% of the flowers yielded fruit. However, when flowers were  kept  open  to  natural  pollination  during  the  day  (covered  at  night),  35%  of  flowers  produced  fruit.  20%  of flowers exposed to natural pollination during the night (covered during the day) produced fruit. Which of the following statements is NOT a plausible explanation of these results ?

TLS Online TPP Program

#Question id: 12252

#Unit 10. Ecological Principles

In a study of interactions between plants, ants and caterpillars, the following experimental treatments were imposed: i) Control (both ants and caterpillars are present); ii) Ant removal; iii) Caterpillar removal; iv) Ant and caterpillar removal. Plus (+) indicates presence and minus (-) indicates absence on plants. The results for plant performance (growth) from this experiment  are shown in the figure below. Plant performance in all treatments were significantly different from each other. Based on these results, which of the following inferences is correct?

TLS Online TPP Program

#Question id: 12253

#Unit 10. Ecological Principles

Both males and females of a fish species show variation in colour. A population of this species consists of 40% blue females, 20% red females, 20% blue males and 20% red males. A researcher catches one fish at random from this population. Given that a male fish is caught, the   probability that it is blue is (Use decimal notation, not fractions or percentage)