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What type of natural selection could have produced birds with these two extreme types of beaks?
Wiki User
∙ 7y ago
The description of extreme beak types suggests disruptive selection, where individuals with either extreme of the trait are favored over the intermediate forms. This could occur if there are distinct ecological niches that benefit birds with specific beak shapes.
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Vikas Babbar
Wiki User
∙ 11y agonatural selection
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What process produced the two different types of beaks shown?
natural selection
What body part of the Galapogos finches appears to have modified by natural selection?
The finches beaks were modified by natural selection. The beak size and shape varied from island to island.
How is disruptive selection different from directional selection?
disruptive selection favors the extremes of a range of selection Disruptive selection refers to natural selection that favors phenotypic extremes. Example (off the top of my head, but based loosely on reality): Consider a population of seed-eating birds with beaks that range in size, so that big beaks are best adapted to eating big seeds, small beaks are best adapted to small seeds, and medium beaks are best adapted to medium seeds. Now suppose that the source of medium seeds goes extinct (perhaps because of a fungal pathogen). The bird phenotype with medium beaks looses its food source; selection favors the big and small beaks.
In selection individuals with both extreme forms of a trait are at a selective advantage?
There are three patterns of natural selection. 1) Disruptive selection: this is when the two extreme forms of a trait are selected for and intermediate forms are selected against. For example plants which can tolerate heavy metal ions are at an advantage on old spoil tips, whereas those which cannot tolerate these ions are at an advantage on uncontaminatied soil. 2) Stabilizing selection: this is when the intermediat forms are selected for and the extreme forms are selected against. A classic example is birth weight in humans. Babies which are much heavier or much lighter than average are more likely to die than average weight babies. 3) Directional selection:this is when one extreme is selected for and the other extreme is selected against. For example in Darwin's finches on the Galapagos Islands, during a drought larger birds with larger beaks are favoured over smaller birds with smaller beaks. See: http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/E/Evolution.html http://www.evotutor.org/Selection/Sl5A.html
What do darwinists believe?
Darwinists believe in the theory of evolution proposed by Charles Darwin, which states that all species of organisms develop and change through natural selection over time. They also believe that all life on Earth shares a common ancestor and that species have evolved to adapt to their environments through the process of natural selection.
How could you use artificial selection to breed pigeons with large beaks?
Artificial selection (or selective breeding) describes intentional breeding for certain traits, or combination of traits. The way to breed pigeons with large beaks is to find pigeons with large beaks of both sexes and mate them and then not allow breeding for pigeons without large beaks. You may also be able to genetically engineer pigeons so that they have large beaks.
Darwin began to formulate his concept of evolution by natural selection after what?
observation of many species and their geographical locations.
How can natural selection lead to speciation?
Because in natural selection heritable traits will be passed down allowing those species to have a better chance at survival, thus making speciation a reality.
What happens to the variation in traits which are under strong natural selection?
It depends on which form is being favored by selection. In directional selection, one of the extremes of the "bell curve" has the advantage. In this case selection will "drive" the variation toward one end. Example: a population of birds where long, narrow beaks have an advantage; variation will be pushed toward longer, narrower beaks until that stops being advantageous. On the other hand, sometimes selection favors the "middle of the road" form. In this case, the variation will be driven toward the middle and the extremes will drop away. For example, a population of moths where a medium shade of coloring has the advantage (not too light or too dark); in this case, you'll get more gray moths, less black and white. This is "stabilizing selection".
What was the effect of natural selection on beak size in the Grants' study?
The Grants studied finches on the Galapagos islands for many years, focusing on the effect of types of food on the size and shape of the finches' beaks. The finches had speciated based on the foods they found available, with some species feeding on large seeds, some on small seeds, and some on other foods. In years with drought in which some foods were scarce, they found that different beak sizes were advantageous than in a wetter year, causing a change in the average beak size seen in the populations. This is important because it is an example of natural selection occurring on a scale that we can easily observe.
What is natural selection how does it drive evolution?
Basically, the ones who have the worst adaptions to survive in the environment it lives in, will die, while the ones with the best adaptions will thrive and breed, gradually making the better adaption dominant in the surviving members of the species. This is how you can have different features (say thicker beaks, longer tails, smaller eyes) in different sub-species of the same species - they've evolved for a different environment, and therefore have different adaptions.
Which feature of galapagos finches was important to Darwin in developing his theory of natural selection?
Darwin noticed that the finches in the Galapagos Islands had different types of beaks. He concluded that this meant they must have evolved these beaks, so that each type could find food.
