By understanding DNA and gene expression, humans have been able to understand how genetic diseases are caused, therefore they have been able to devise gene therapy and other technologies to treat such disease. Second, the understanding has also allowed humans to devise plants that are resistant to pests and drought hence increasing crop yields.
A negative aspect of this understanding is the issue of bioterrorism. In the wrong hands, this technology can be used against society. The technology can be used to modify organisms to make them deliberately harmful to humans. Second is the issue of bioethics. This technology can be used to enhance humans and result to an ‘arms race’ between human races that can tear down the social fabric.
Answer:
Yes both are different. In directional selection one of the extreme traits is favored, whereas in disruptive selection both the extreme traits are favored.
Explanation:
Directional: If selection acts to eliminate one extreme form and supports the other extreme then the peak shifts in the direction which is selected by the nature.
Disruptive: If the selection does not favor the mean character value, rather favors both the peripheral character values then this kind of selection is called disruptive selection.
The answer is pronuclei. A pronuclei is the state of the
nucleus of either the sperm or the ovum after the sperm has entered the ovum
but the two nuclei have not yet fused. When the sperm enters the ovum, the membrane
of the sperm pronuclei dissolves hence leaving no barrier for the two genetic
materials to combine.
Stem cells are what allow planaria to grow and regenerate as the stem cells can change into any of the cells that make up the planaria.
Finches adapt to the new conditions such as drought by changing the size, shape and depth of their beaks. Beak morphology varies according to drought conditions. Since after the drought, vegetation dries out and the hard, big, tough seeds remain, only the finches with deep beaks will survive. Finches adapt via their beaks to different foods sources and different local conditions.
