Darwin's finches are a traditional illustration of an adaptive radiation. Their ancestor came on the Galapagos Island about two million years ago. With time Darwin's finches have developed into fifteen different species separated on the basis of beak shape, body size, and feeding and song behavior.
The population of finches possesses the tendency of evolving rapidly in response to a changing environment. However, they can also get extinct in condition if the weather fluctuates too briskly between the dry and wet seasons. This would most likely take place due to the immigration of genes and mutations within the genes that are conducted on to the next generations.
<span>There are numerous proteins in muscle. The main two are thin actin filaments and thick myosin filaments. Thin filaments form a scaffold that thick filaments crawl up. There are many regulatory proteins such as troponin I, troponin C, and tropomyosin. There are also proteins that stabilize the cells and anchor the filaments to other cellular structures. A prime example of this is dystrophin. This protein is thought to stabilize the cell membrane during contraction and prevent it from breaking. Those who lack completely lack dystrophin have a disorder known as Duchene muscular dystrophy. This disease is characterized by muscle wasting begininng in at a young age and usually results in death by the mid 20s. The sarcomere is the repeating unit of skeletal muscle.
Muscle cells contract by interactions of myosin heads on thick filament with actin monomers on thin filament. The myosin heads bind tightly to actin monomers until ATP binds to the myosin. This causes the release of the myosin head, which subsequently swings foward and associates with an actin monomer further up the thin filament. Hydrolysis and of ATP and the release of ADP and a phosphate allows the mysosin head to pull the thick filament up the thin filament. There are roughly 500 myosin heads on each thick filament and when they repeatedly move up the thin filament, the muscle contracts. There are many regulatory proteins of this contraction. For example, troponin I, troponin C, and tropomyosin form a regulatory switch that blocks myosin heads from binding to actin monomers until a nerve impulse stimulates an influx of calcium. This causes the switch to allow the myosin to bind to the actin and allows the muscle to contract. </span><span>
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Answer:
<u><em>Ancestors</em></u>
Explanation:
Ancestors can be described as the persons from which a particular human being originated. In a broader perspective, it is referred to family history of a person. Scientists believe that all organisms on Earth originated from a common ancestor which were the prokaryotes. The prokaryotes with time gave rise to the eukaryotes. Common descent is the phenomenon in which organisms having common ancestors are referred.
Answer:
the answer is C. the lymph system
<span>B.The existence of vestigial structures
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Vestigial structures have been used for long by evolutionists to support the theory of evolution. These organs are believed to have been in use in the past lives but as the species adapts to new forms of life and lifestyle,the vestige organs becomes obsolete,but are not removed by the body. An example of vestige organs in human being are the appendix,tail bone,and mammalian grands in men.
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