 In the specific interaction, co-evolution, first the contents, definition of co-evolution, a role of nature selection in co-evolution, flowering plants and the nectar feeders are of the pollinators and hummingbird and the passion flowers. So first the co-evolution, students if we talk about co-evolution, co-evolution is also a type of inter-specific interaction, co-evolution be inter-specific interaction type in which usually there is a phenomenon in which different species interact with each other. So the interaction between species that is the inter-specific interaction. So what is co-evolution? Evolution means evolve, change. Co-evolution means that when different species interact with each other, both species they evolve accordingly. So by definition, co-evolution is the phenomenon in which the different species they interact in such a way that they exert a specific selection pressure or the selective change on the other species. One species exert a selective change on the other species. So the result is the evolution in the species. It may be evolution in one species, mostly it is evolution in both species. So how co-evolution occurs in nature? If we talk about nature, when is the co-evolution? So simply co-evolution basically it happens in nature when especially there is a competition between the organisms. Different species have competed, then there is a co-evolution that evolves. Similarly, the second type is the predated prey relationship. In predated prey relationship there is also the co-evolution. The predator evolves and the prey evolves. Similarly, if I explain it a little bit, what is predated prey evolution? Predator catches the prey efficiently. In different species, when evolution occurs, with the passage of time it will be better. So that it can capture the prey easily. So what is evolution in the predator? That is why to facilitate the hunting, the predation. What is the evolution of the prey? What will the prey do accordingly? It will modify itself. Because of which, if the predator evolves and becomes better, the prey becomes as efficient as possible to survive. So if evolution occurs on both sides, then the net result will be zero. It will be a balanced evolution in which both groups will evolve. But if one group evolves more, the other evolves more, then what will happen? The group that evolves more will ultimately evolve. If the predator evolves more, then the prey will not be able to survive in that habitat. The ecological balance will end. If the prey evolves more, then the predator will not be able to capture it. The result will be that there will be an ecological imbalance. There will be an imbalance in nature. So normally, when the species they compete, and they evolve, then natural selection favors the specific rectors. So what does natural selection do? It favors the specific rector. If there is a suitable rector, then what will it do? It will promote it. So again, if there is a balance, if there is a balance on both sides, in predator prey or in other things, then what will the net do? No one is the winner. So here we have some examples of co-evolution. The first example of co-evolution is the pollinators. Pollinators and the flowering plants. The concept of co-evolution is that initially, most of the plants used to be pollinated by the wind. What was there through the wind? There was a pollination. The wind would go through the wind and fall on the stigma. So this process would work. With the passage of time, the plants they operate some more efficient ways. The plant adopted some more efficient ways. Number one, the plants, they became more bright in color. The colors of the flowers became brighter. They also produce different types of scents. The scents would be nectar production. So what was the result? When different types of scents, like bright coloration, or different types of scents, the pollinators were attracted to the plants. What happened now is that to attract insects and birds, the plants evolved themselves. So this is the one example of co-evolution. What is one group doing? They are evolving themselves. Similarly, the other example of plants and pollinators is the hummingbird. Those plants which are pollinated by the hummingbirds. In nature, there are many plants which pollinate the hummingbirds. Normally, those plants which are pollinated by the hummingbirds are pollinated by the hummingbirds. That is, pollination. Those plants have red color. What happens to those plants? They have red color and they are tubular shaped. Now if we look at this, what is the red color of the plants? The hummingbird's sense of smell is not as strong as the red color which can be easily recognized. Because of the red flower, this specific plant will attract the hummingbird because of the red flower. The tubular portion of the hummingbird is long, so it can feed the nectar from the tubular flowers. When the nectar feeds, it will be pollinated. The second example, the next example is the hummingbird and the passion flower. The first example is the general flowers Here we have a very specific example. There are many species of hummingbirds. One of them is the encephera encephera. The encephera encephera is one species of hummingbird. There are many species of hummingbird. This specific species of hummingbird it feeds on the passion flower. What does it do? It feeds on the passion flower. If we look at the relationship between the two, the nectar of the passion flower is a very deep store. The nectar in the flower is a very deep store. The other birds cannot feed it. The other birds or other animals cannot feed the nectar so they cannot pollinate it. Only the encephera hummingbird will come to these specific passion flowers. They will feed the nectar and pollinate it. There are two important things here. One is that the passion flower is specifically pollinated by the hummingbird. The encephera encephera will only be pollinated by the specific species. The other important thing is that the encephera hummingbird is saved from competition. What is the specific competition? There is a reduced competition between the species.