Darwin’s Finches: Darwin observed that beak shape varies among finch species. He postulated that the beak of an ancestral species had adapted over time to equip the finches to acquire different food sources. This illustration shows the beak shapes for four species of ground finch: 1. Geospiza magnirostris (the large ground finch), 2. G. fortis (the medium ground finch), 3. G. parvula (the small tree finch), and 4. Certhidea olivacea (the green-warbler finch) the Grants measured beak sizes in the much-reduced population, they found that the average bill size was larger. This was clear evidence for natural selection of bill size caused by the availability of seeds. The Grants had studied the inheritance of bill sizes and knew that the surviving large-billed birds would tend to produce offspring with larger bills, so the selection would lead to evolution of bill size. Subsequent studies by the Grants have demonstrated selection on and evolution of bill size in this species in response to other changing conditions on the island. The evolution has occurred both to larger bills, as in this case, and to smaller bills when large seeds became rare.
Option 1 is the correct answer
The neurotransmitter is Dopamine.
The following combinations of neurotransmitters seem to be at play in
those who suffer from ADHD is Serotonin, dopamine, and norepinephrine. Neurotransmitters,
also known as chemical messengers, are endogenous chemicals that enable
neurotransmission. They transmit signals across a chemical synapse, such as a
neuromuscular junction.
Answer:
4 percent (4%)
Explanation:
A single crossover occurs between two (non-sister) chromatids belonging to homologous chromosomes. In this case, 16 percent of the meioses have a single crossover, thereby it will produce 8 percent of the chromosomes with the original (parental) combination in the progeny and the remaining 8 percent should be recombinants. From this result, it is reasonable to conclude that half of these recombinants should be 'Br' (and the other remaining 4 percent should be recombinants 'bR'), and therefore the answer is 4 percent (4%).
<span>Most membrane channels allow passage by simple diffusion of small inorganic ions of a specific type and may also be voltage gated. The solute binds to a protein carrier on one side of the membrane and is released on the other side after the transporter undergoes a change in shape, the movement of molecules across a cell membrane from a region of their lower concentration to a region of their higher concentration in the direction against some gradient or other obstructing factor.</span>
