Survival Rate

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Survival Rate


in biology, the average probability of survival and reproduction of the organisms of each generation of a species (population). The survival rate is measured by the ratio of the number of adults that reproduce to the number born in each generation (or the number of eggs de-posited, spawn laid, seeds ripened, and so forth).

Under unfavorable conditions the survival rate (like fertility) decreases, and a population declines. Under favorable conditions the survival rate increases, stabilizing or augmenting the population. The survival rate increases by many orders in the course of progressive evolution. Thus, the average survival rate increases from 10~7-10~6 percent in bacteria, unicellular organisms, and plants to 10-30 percent in higher animals. This is associated with the development of several systems that promote the safety of the organism and reduce loss in all phases of ontogeny (development of multicellularity, differentiation of organs, perfection of self-regulation and homeostasis, increase in the amount of yolk in an egg, shift to internal fertilization, viviparity, active con-cern for offspring, and so forth). An increase in the survival rate during evolution is accompanied by a regular decrease in fertility. For example, in animals with small eggs deficient in yolk that are laid directly in water, the females deposit many million eggs at a time; however, in species that have large well-protected eggs and are capable of guarding their young, the females deposit only ten to 100 eggs. Maintenance of the optimum survival rate is important for evolution because higher rates can dangerously lower the effectiveness of natural selection and the evolutionary flexibility of the species.

The term “survival rate” is also used in research on the effect on the organism of various unfavorable factors, such as ionizing radiation. It means the percentage of organisms surviving exposure to such factors.


References in periodicals archive ?
n 9% Improvement in fiveyear survival rates for kids' cancers since 2001
But survival rates for other types of cancer England are slow to improve and in some cases getting worse, statistics revealed.
PHILIPPINE micro, small and medium enterprises (MSMEs) exhibit better survival rates when they export to non-Asean countries than to Asean member-nations, a recent study published by state think tank Philippine Institute for Development Studies (PIDS) said.
There is hardly any study which investigates direct link between under-five survival rate and availability of food in case of Pakistan.
When recent publications on the effect of resection type on survival rates were investigated, the primary finding was that lobectomy is associated with a better prognosis for stage 1 patients (27).
Liver, lung and pancreas cancer had the worst survival rates in 2010-14, while patients were statistically more likely to survive over one or five years if they had melanoma (skin), prostate and breast cancer.
Cancer survival rates in the UK are among the worst in Europe, which many believe is down to late diagnosis.
The one-year survival rate between 2006 and 2008 was 94.5%, one of the lowest rates in England and worsening on average at 0.7% a year.
The survival rate of offspring is an important criterion in determining the economic value of offspring born which is important for all animal producers (Akcapinar and Ozbeyaz 1999).
Conclusion: In this study, the 10 year-graft survival rate for pediatric renal transplantation was 78.1%.
“For certain types of cancer such as breast cancer, the five year survival rate is now 91.4 percent,” according to Jesse Slome, executive director of the American Association for Long-Term Care Insurance.

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