Ecological models commonly have limited applications because the models included and the whole of them are from generalizations. And another reason is because ecological models focus on a population level and also an individual level which affects it applications and it caused for limited distributions.
Answer:
having more air spaces around the spongy mesophyll cells
The probability of life evolving into a complex form is one of the factors in the Drake equation. Drake himself estimated that probability as 1.0, for what that's worth.
<span>He had that confidence precisely because descent-with-variation seems pretty certain to be a universe process because it's so straightforward. If you have something that reproduces imperfectly, eventually more complex versions will be the result. Even the "natural selection" part is optional if you were just imagining searching through the vast space of genetic possibilities, but finite resources make selection inevitable.</span>
It is believed that this happens because some signals that regulate development are the same between different species and because <span>they share ancient genes. </span>These ancient genes are expressed during a middle "phylotypic stage" of embryonic development for all species.
For example, human and animal embryos go through very similar stages of early development and share similar features such as tails and gill-like structures. The major difference appears to be how long it takes to reach each of these same stages.
