More reproductions, means more energy consumption therefore, some organism develop the habit of living longer instead of reproducing more to extend their species life span. So I am not so sure about the last bit of the diagram. Do species live longer to better reproduce or save energy?
The environment determines if a species will evolve towards higher fecundity (many offspring) or towards longer life expectancy.
You should read up on
r/K selection theory
quote:
r-selection (unstable environments)
In unstable or unpredictable environments, r-selection predominates as the ability to reproduce quickly is crucial. There is little advantage in adaptations that permit successful competition with other organisms, because the environment is likely to change again. Traits that are thought to be characteristic of r-selection include: high fecundity, small body size, early maturity onset, short generation time, and the ability to disperse offspring widely.
Organisms whose life history is subject to r-selection are often referred to as r-strategists or r-selected. Organisms with r-selected traits range from bacteria and diatoms, through insects and weeds, to various semelparous cephalopods and mammals, especially small rodents.
K-selection (stable environments)
In stable or predictable environments, K-selection predominates as the ability to compete successfully for limited resources is crucial and populations of K-selected organisms typically are very constant and close to the maximum that the environment can bear (unlike r-selected populations, where population sizes can change much more rapidly).
Traits that are thought to be characteristic of K-selection include: large body size, long life expectancy, and the production of fewer offspring that require extensive parental care until they mature. Organisms whose life history is subject to K-selection are often referred to as K-strategists or K-selected. Organisms with K-selected traits include large organisms such as elephants, trees, humans and whales, but also smaller, long-lived organisms such as Arctic Terns.
I found a pic too: