Exploratory Activity on Bird Beak
In the 19thcenturyCharles Darwin, a biologist from England observed that there were variations in traits of the same species from the same population and that variations may increase their chance to survive and reproduce. The variations are achieveddue to both the recombination of genes during sexual reproduction and mutations. The selection of a best suited type is a function of the environment in which the species lives and is referred to theoretically as natural selection. This isbelieved to be thedynamic force of evolution.
Factors responsible for differential survival of organisms and consequently their ability to reproduce:
(a) changes in abiotic factors in the habitat such as temperature or pH changes,
(b) Availability of resources such as nesting sites or food,
(c) Interspecies interactions such as predator-prey relationships.
Availability of resources play a very important role in the survival of the organism, if resources are less than Compiton will increase and the organisms who die as a result of this competition were not totally random, but he found that those organisms more appropriate to their environment were more liable to survive. This resulted in the phrase "survival of the fittest".
So we can say that those alleles of a species that are favored in the environment will become more frequent in the genomes of the species, and as a result the species survival rate increases.
In this activity six stations are set up to having different types of food that birds might eat, as follows:
Station 1: In this station Sunflower seeds are scattered on a table anda bird having pier type of beak can eat these sunflower seeds.Because with the help of plier type beak shape sunflower seed can easily picked.
Station 2: In this station Colored water is filled in a long, narrow vase which represents flower nectar is placed on the table and a bird having drinking straw type beak can penetrate and extract from the vase and survive.
Station 3: Rice grain stucked inside the piece of Styrofoam, which represents small insects in tree bark and to eat these insects like rice grain birds having beak like needle-nose tweezers are present, because this type of beak is long and sharper and is capable to pick the insect from the tree trunk .
Station 4: On this station 3-4 large piece of Marshmallows scattered on the table which represents meat from small animals and for eating this type of food bird having pliers type of beak is present, because meat is soft and to chew it beak should have small teeth like structure which is present in pliers.
Station 5: On this station Ice cubes in water is present which represent fish in a lake, to eat these fishes which are present in lake bird having slotted spoon type beak is present, because on the fishes are to be captured and not water holes are present in the beaks so that the excessive water should drain out and also the beak is broader in the front so that fish can be easily captured and hold for a while.
Station 6: On this station some herbs placed in the bowl of water, which represents small plants and animals floating in a lake, to pick these herbs from lake bird having slotted spoon type beak is present, because of its broader and slotted nature only the floating herbs and insects is captured and water is drain out.
Now from the above activity we are able to understand that to eat different types of foodbirdsreqire different types of beak and because of that we have different species of birds with in the same population.
If for instance the usual food changes, for example small insects hiding deeper inside the tree trunk than the birds developed more long and sharper beaks like needle nose tweezers type so that they are able to pick the insects from the deeper part of the tree.
Take another example if sunflower developed harder shell in that case to break the shell and to remove sunflower seed the beaks should be plier type having more teeth to crush the harder coat.
From the above activity
Asit wasillustrious in the introductory paragraph above, natural selection is achieved by the combination of several different mechanisms that cause evolutionary change in populations and these changes which are present in the genome of a population inherited from one generation to the next because of which, organisms become better adapted to their environment.
Causes of Natural Selection:
1. Some Individuals within a populationmay vary; they are not all identical.
2. Some variants are "better" and most fitted to the environment than others. As a result, their population increases.
3. The traitsfor that species which vary from the others are heritable.
If the above items are correct, then the "better" individuals will have extra success reproducing and because of that will have more offspring. In consecutive generations, more offspring will have the better traits; and as a result the population will change which indicates evolution.
So, from the above activity it is clear that if seeds become more harder and insects penetrate more deeper inside the bark than only those birds survive which have the suitable beak to neutralizes the effects on the nature and location of food. Because of the better adaption those birds reproduce fastly and as result more and more population of that species formed and evolves a different species with time.