1. humans drill into the geosphere for oil and dig up rocks
2. humans drill into the geosphere to get water (hydrosphere) to use for crops and personal uses
Answer:
C. Beak size is an inherited trait in the finch population under study.
D. Birds that could eat larger, tougher seeds survived and reproduced during the drought.
E. Beak size varies among the birds in the finch population under study.
Explanation:
The presence of genetic variations among the individuals of a population is required for natural selection to be operative. Natural selection targets the beneficial genetic variations present in the population. Natural selection refers to the differential reproductive and survival success of organisms of a population due to some beneficial genetic traits. These organisms with beneficial genetic traits are able to survive and leave more progeny under prevailing conditions.
If the natural selection has occurred in the ground finch population for the beak size, the beak size should be a genetic trait since natural selection works on genetic traits only. The finch population should have variations with respect to the beak size. The finches having the larger beak size that enabled them to feed on larger, tougher seeds should have higher survival and reproductive fitness during the drought.
Under these conditions, natural selection would favor the finches with larger beak size and would eventually result in an increase in the average beak size of the future generations.
Answer:
Hemoglobin is responsible for binding and transporting oxygen in the body. It is a tetrameric protein that is found in high concentration in red blood cells (erythrocytes, red blood cells). Each hemoglobin molecule is made up of four subunits: two of the alpha type and two of the beta type, and each subunit can bind an oxygen molecule through its heme group.
Structure studies have shown that hemoglobin can adopt two conformations, called T (tense) and R (relaxed). Deoxyhemoglobin (in blue) is in state T, and the union of oxygen (in red) causes the transition to state R. The animation shows a close view of the heme group (in white, balls and rods) of one of the subunits of hemoglobin. In the deoxygenated state (T), the iron atom is not coplanar with the rest of the heme group due to its association with the histidine side chain. The union of oxygen displaces the iron atom so that it remains coplanar with the rest of the heme group, which in turn drags histidine, producing a larger-scale conformational change that affects the entire protein.
Hemoglobin can be considered as a tetramer formed by two alpha-beta dimers. The conformational change associated with the transition from T to R mainly affects the relative position of these two dimers (rather than the interactions between the alpha and beta subunits within a dimer). This is illustrated in the last stretch of the animation (drawn in black and white).
