Answer:
the name of the organelle is Golgi Body. option B.
Answer:
In many senses, Darwin's theories created a societal transformation. Darwin's theory consisted of two main points; 1) diverse groups of animals evolve from one or a few common ancestors; 2) the mechanism by which this evolution takes place is natural selection.
Explanation:
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Complete question:
In the 1890s, Northern elephant seals were hunted almost to extinction. An unknown population of less than one hundred animals managed to survive on the tiny island of Guadalupe off of Mexico. The current population of over 100,000 is thought to be derived from that tiny remnant population. Compared to the Southern elephant seals (which did not experience such a bottleneck), the Northern elephant seals likely have -------- (Lower - Higher) genetic diversity and -------- (Lower - Higher) levels of genetic diseases.
Answer:
In the 1890s, Northern elephant seals were hunted almost to extinction. An unknown population of less than one hundred animals managed to survive on the tiny island of Guadalupe off of Mexico. The current population of over 100,000 is thought to be derived from that tiny remnant population. Compared to the Southern elephant seals (which did not experience such a bottleneck), the Northern elephant seals likely have Lower genetic diversity and Higher levels of genetic diseases.
Explanation:
Genetic drift is the random change that occurs in the allelic frequency of a population through generations. The magnitude of this change is inversely related to the size of the original population. These changes produced by genetic drift accumulate in time. Eventually, some alleles get lost, while some others might set. Genetic drift affects a population and reduces its size dramatically due to a disaster or pressure-bottleneck effect- or because of a population split -founder effect-.
In the exposed example, extensive hunting acted as a pressure that reduced the number of Northern elephant seals to fewer than 100. This population experienced one or many generations of small size since these animals were affected by hunting. As the survivors did not have the whole genetic pool of the original population, the population size might have recovered to a current population size of 1000,000 individuals, but <u>the genetic pool might have not</u>. When the small population increases in size, it will have a genetically different composition from the original one. In these situations, there is a<u> reduced genetic variability</u>, with a possibility of developing a peculiar allelic component. If the survivors in the population carried or developed a mutation, probably this mutation passed from generation to generation. It will involve more individuals each time and<u> increase the probability of developing a genetic disease</u>.
Answer:
In muscles contraction the correct order of the steps are: A (Nerve impulse reaches the muscle), B (Action potential travels down T-tubules), C (Calcium binds to troponin), D (Tropomyosin moves).
Explanation:
Skeletal muscle contractions are based on different physiological and biochemical phenomena that happen in every cell. These phenomena are due to stimulation produced by somatic motor neurons, which axons get in contact with muscle fibers through a neuromuscular synapse. In rest, attraction strengths between myosin and actin filaments are inhibited by the tropomyosin. When an action potential is originated in the central nervous system, it travels to the somatic motor neuron membrane: the muscle fiber, and activates the calcium channels releasing it in the neuron. Calcium makes vesicles to fuse with the membrane and release the neurotransmitter named acetylcholine (Ach) into the synaptic space in the juncture. Then, Ach binds to its receptors on the skeletal muscle fiber. This causes the ion channels to open, and positively charged sodium ions cross the membrane to get into the muscle fiber (sarcoplasm) and potassium get out. The difference in charges caused by the migration of sodium and potassium makes the muscle fiber membrane to become more positively charged (depolarized). The action potential caused by this depolarization enters the t-tubules depolarizing the inner portion of the muscle fiber. This activates calcium channels in the T tubules membrane, that make the calcium be released into the sarcolemma. At this point, tropomyosin is obstructing binding sites for myosin on the thin filament. When calcium binds to the troponin C, the troponin T alters the tropomyosin by moving it and then unblocks the binding sites. Myosin binds to the uncovered actin-binding sites, and while doing it ATP is transformed into ADP and inorganic phosphate. Z-bands are then pulled toward each other, thus shortening the sarcomere and the I-band, and producing muscle fiber contraction.
