Why did the thickness of the beak increase during evolution?

Evolve primarily to survive. It's to better capture the food. Plays a protective role.

The increase in the depth of the beak is due to the current environment.

In 1977, a severe drought struck the island of Greater Daphne. When drought causes food shortages for the island's ground finch, the smaller and softer seeds are the first to be consumed, resulting in starvation of those who are unable to eat the larger, harder seeds. Because beak types are heritable, surviving ground finches pass on the traits that helped them survive drought to the next generation, and measurements show that by mid-1979, the thickness of the beak had indeed increased!

So it was called because he was often catching food on the ground. The thickness has changed because it catches food better.

Evolved to eat hard food.

It is forced by the current biological environment.

In order to be able to catch the prey quickly and accurately.

In order to better shred the food, in order to survive.

It must be that this kind of evolution is more conducive to survival, so why not evolve if you can live less hard.

Because it's the result of natural selection.

a. Figure 1 The difference between the four kinds of beaks is different in different environments, and the direction of natural selection is different, and a is wrong;

B. The formation of the two types of winged bijels of insects in Figure 2 is determined by natural selection, B is wrong;

c. The two body colors of the birch moth are the same species, and the sign of speciation is the formation of reproductive isolation, c is wrong;

d. The relationship between the two animals in the figure can promote co-evolution between the two, and the presence of predators is conducive to increasing species diversity, d is correct

Therefore, d

a. The difference between the beaks of the four kinds of ground sparrow in Figure 1 ** In different environments, the direction of natural selection is different, and a is wrong;

B. Fig. 2 The formation of the two types of wings of insects is determined by natural selection, b is wrong;

c. The two body colors of the birch moth are the same species, and the sign of speciation is the formation of reproductive isolation, c is wrong;

d. The relationship between the two animals in the figure can promote co-evolution between the two, and the presence of predators is conducive to increasing species diversity, d is correct

Therefore, d

1) The method of statistics on animal populations is the marker recapture method

2) From June 1976 to early 1978, it can be seen that the population of ground finches declined by about 1 000 individuals, and the key factors leading to the decline were the decline in seed abundance and the increase in the proportion of large, hard nuts in the diet

3) Drought or rainfall leads to changes in food composition, and through natural selection, the beaked ground finch becomes an adaptor to the environment, and eventually the fittest survive, and the unfit are eliminated by the cover

4）d%=dd%+1

dd%=10%+1

85%=，d%=dd%+1

dd%=5%+1

5) The beak depth of the ground finch decreased compared to before the El Niño event, and the richness and hardness of the food should be analyzed, due to the abundant rainfall, the abundance of seeds increased, the average size and hardness of nuts decreased, the survival chances of the type with small beak depth increased, and the frequency of genes with low beak depth increased in the offspring produced through sexual reproduction

So the answer is: 1) Flag recapture method.

2) 1000 seed richness and nut size and firmness.

3) Large beak survival of the fittest.

5) Abundant rainfall, the abundance of seeds, the average size and firmness of nuts decreased, the chances of survival of jujube people with small beak depth increased, and the frequency of genes with small beak depth increased among the offspring produced by sexual reproduction