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The rate of living theory postulates that the faster an organism's metabolism, the shorter its lifespan. First proposed by Max Rubner in 1908, the theory was based on his observation that smaller animals had faster metabolisms and shorter lifespans compared to larger animals with slower metabolisms. [ 1 ]
Life history theory ... Examples of some major life history characteristics include: ... Growth rates, developmental markers and life histories in 21 small-scale ...
The theory was popular in the 1970s and 1980s, when it was used as a heuristic device, but lost importance in the early 1990s, when it was criticized by several empirical studies. [5] [6] A life-history paradigm has replaced the r/K selection paradigm, but continues to incorporate its important themes as a subset of life history theory. [7]
This example of a survival tree analysis uses the R package "rpart". [8] The example is based on 146 stage C prostate cancer patients in the data set stagec in rpart. Rpart and the stagec example are described in Atkinson and Therneau (1997), [9] which is also distributed as a vignette of the rpart package. [8] The variables in stages are:
For example, oysters produce millions of eggs, but most larvae die from predation or other causes; those that survive long enough to produce a hard shell live relatively long. The number or proportion of organisms surviving to any age is plotted on the y-axis (generally with a logarithmic scale starting with 1000 individuals), while their age ...
"Now, here, you see, it takes all the running you can do, to keep in the same place." — Lewis Carroll [4]. In 1973, Leigh Van Valen proposed the hypothesis as an "explanatory tangent" to explain the "law of extinction" known as "Van Valen's law", [1] which states that the probability of extinction does not depend on the lifetime of the species or higher-rank taxon, instead being constant ...
Increasing obesity rates in high-income countries are further confirming the epidemiological transition theory as the epidemic leads to an increase in NCDs. The picture is more nuanced in low- and middle-income countries, where there are signs of a protracted transition with the double burden of communicable and noncommunicable disease.
Investigation of the tenacity and versatility of life on Earth, [116] as well as an understanding of the molecular systems that some organisms utilise to survive such extremes, is important for the search for extraterrestrial life. [95] For example, lichen could survive for a month in a simulated Martian environment. [162] [163]