Muscle cells have an abundant, modified smooth ER called the sarcoplasmic reticulum.

The release and reuptake of Ca2+ by the sarcoplasmic reticulum trigger myofibril contraction and relaxation, respectively

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#Id: 3165

#XL - T Zoology

Ronald A. Fisher, John B. S. Haldane and Sewall Wright- which showed that mutation and natural selection together cause adaptive evolution.

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#Id: 3166

#XL - T Zoology

 Neutral theory of molecular evolution- Developed by Motoo Kimura, who argued that most of the evolution of DNA sequences occurs by chance (genetic drift) rather than by natural selection.

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#Id: 3167

#XL - T Zoology

Theory of recapitulation - Ernst Haeckel
He proposed that the embryonic development of an individual organism (its ontogeny) followed the same path as the evolutionary history of its species (its phylogeny).

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#Id: 4307

#XL - T Zoology

Bergmann’s rule: populations in colder climates tend to have greater body mass than those

in warmer climates. This pattern is so common that it has a name.

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#XL - T Zoology

Haldane’s rule: hybrid sterility or hybrid inviability is often limited to the heterogametic sex. (The heterogametic sex is the one with two different sex chromosomes, while the homogametic sex has two sex chromosomes of the same type).

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#Id: 4309

#XL - T Zoology

Hamilton’s rule: It states that an allele that causes an altruistic behavior will spread if the following condition is met (rb>C)