Reproductive Advantage

Think of the case where there are two BU one is able to perform the same functions as the second, but it can do so with one half the energy requirements. If each BU is an animal, which is most likely to be caught and eaten by a predator If each BU is a predator, which is most likely to chase and 

In each of these cases, the answer is clearly that the BU with the energy advantage is the winner of the competition. Only in the instance where competition is at a minimum, say, for example, for the first species in a virgin environment, will there be little primary reason to reduce energy costs. However, as soon as the second species arrives, or even as soon as the number of individuals of the first species increases to the point that they force significant intraspecific competition, there will be an advantage to those individuals that can make more efficient use of resources. Thus, there is a tendency to minimize dependence upon the environmental sources of energy and nutrients. 

Each biological form, function, and action has a cost and a benefit. Survival considerations demand that 

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Detterman One complication I wondered about, is exactly what is a deleterious mutation Many of these genes that in the homozygous state produce mental retardation, in the recessive state actually confer some reproductive advantage, even though they may lower IQ. There is evidence for phenylketonuria, for instance, and Tay Sach s disease. 

Since then, there has been a reproductive advantage to those whose genes encode altruistic, rather than aggressive or violent behavior. Survival and reproduction are enhanced by societal rules, freedom of the individual, and secular governments. Genes that encode kindness and altruism supplement those encoding selfishness and violence. 

The belief that altruism has been the result of natural selection goes back to Charles Darwin, who said that people would risk their lives to save others. People are programmed by their genes to help their family. Altruistic genes are passed on from one generation to another because cooperation gives people a reproductive advantage. 

In flowers exposed to pollinators, it is possible that nectar secretion ceases if there is not pollinator in the area or can be reabsorbed in old or pollinated flowers (Cruden et al., 1983). A nectar production without reabsorption may be have an impact on reproductive biology (Galleto Bernardello, 1995). Therefore, plants reabsorb nectar from aging flowers and utilize its carbon in developing seeds and this is a reproductive advantage (Zimmerman, 1988). 

The power expended by the heart has no particular advantage for an organism this power does not directly aid reproduction, nor does it directly improve survival. As long as there is adequate blood flow, the organism can both survive and reproduce. Any extra power expended by the heart actually reduces the capacity of an individual to survive a physical challenge, so there is both a survival and reproduction advantage to reduce expended power as much as possible and still provide adequate circulation. 

Communications mechanisms must be fast enough to enable the control system to respond in a timely manner. Humoral communications cannot be used for fast responses, and many unmyelinated nerve fibers are also too slow for many purposes. The organism that can transmit information and process it the fastest often has a survival and reproductive advantage therefore, some specialized communication means (such as nerve fibers in myelin sheathes) have developed. 

Long-term changes to a species occur only if there is a reproductive advantage. 

The biological world is a very competitive place, with BU of aU kinds attanpting to use environmental resources to their exclusive advantage, and to the disadvantage of others. Competition is what drives BU to adapt to their environments and competition is what eventually selects for those genes that have a reproductive advantage. 

Allelopathy is the term used for plants that produce chemical compounds harmful to nearby competitor plants. Such plants have a growth and reproduction advantage without competition for resources. Two plants exhibiting allelopathy are black walnut trees and canola (rape). 

Look through the pages of a newspaper that announces engagements and weddings. Note the similarities between faces of the couple. Why do you suppose similar features are attractive Explain in terms of reproductive advantage to the species. 

War is ancient. That it traditionally exposes to maximum danger a biologically surplus and relatively powerless subset of the population— young males—suggests that in some circumstances of traditional intersocial conflict it confers reproductive advantage. Nor were mass slaughters ever... 

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