Living organisms also contain a lot of hydrogen, oxygen, nitrogen, sulfur, and phosphorous. Those atoms combine together to form complex molecules of various types: proteins, carbohydrates, lipids, and nucleic acids.
Answer:
- Interruption in the genetic flow between separated groups
- The emergence of new mutations in each of the groups, and their accumulation in time. Slow and gradual differentiation between populations.
- Genetic divergence by natural selection and reproductive isolation
- Prezigotic isolation mechanisms
Explanation:
Allopatric speciation consists of the geographic separation of a continuous genetic background that can give place to two or more new geographically isolated populations. These separations might be due to migration, extinction of geographically intermediate populations, or geological events. In this speciation, some barriers impede genetic interchange, or genetic flux, as the two new groups that are separated can not get together and mate anymore. These barriers might be geographical or ecological.
The process of allopatric speciation involves different steps that affect organisms:
- The emergence of the barrier.
- Interruption in the genetic interchange
- The occurrence of new mutations and their accumulation in time in each population. Slow and gradual differentiation.
- Genetic divergence by natural selection and reproductive isolation makes it impossible for the two groups to mate even if the barrier disappears.
- Prezigotic isolation mechanisms will be favored by selection if occurs a secondary contact between the new species in formation.
Answer:
C3 photosynthesis produces a three-carbon compound via the Calvin cycle while C4 photosynthesis makes an intermediate four-carbon compound that splits into a three-carbon compound for the Calvin cycle. Plants that use CAM photosynthesis gather sunlight during the day and fix carbon dioxide molecules at night.
Explanation:
Answer:
The correct option is D.
Explanation: The options attached to this question are given below:
A) Bacteria from other animals replace those killed by the antibiotics.
B) The few surviving bacteria that are affected by the antibiotics develop immunity to the antibiotics, which they pass on to their progeny.
C) The antibiotics cause new mutations to occur in the surviving bacteria, which results in resistance to antibiotics.
D) The antibiotics kill susceptible bacteria, but the few that are naturally resistant live and reproduce, and their progeny repopulate the host animal.
E) The antibiotics persist in soil and water.
Antibiotics are sometimes used in animals to control infections. With time, the microbes that are been targeted with the antibiotics usually develop mutations, which makes the antibiotics to become ineffective, thus, the antibiotics will only be able to kill the susceptible microbes while the ones that have developed resistance will remain and give birth to young ones that are also resistant to antibiotics.
