Category: Uncategorized

CONSTRAINTS ON PHENOTYPE. "The common theme of all of the above is constraints on phenotypes. Allocation, antagonistic pleiotropy, mutational decay, and the laws of physics are all reasons why organisms can’t build (or can’t maintain, over evolutionary time) certain phenotypes. Trade-offs reflect constraints on the range of phenotypic options that are open to organisms.” https://lnkd.in/dGaAzSA View in LinkedIn

REASONS FOR TRADE-OFFS. "Allocation is a big one: a unit of energy, materials, or time that an organism uses to do one thing (say, build a defensive structure) cannot be used to do something else (say, reproduce). Antagonistic pleiotropy is another big one: a mutation that improves one biological function often degrades another (although this is presumably not an ultimate explanation for trade offs, since one can ask why we expect antagonistic pleiotropy). Mutational decay is a third: a mutation that degrades an unused function (think cave fish eyes) will be selectively neutral." https://lnkd.in/dGaAzSA View in LinkedIn

DEVELOPMENTAL TEST. "When sections are cut from a Drosophila imaginal disc, adjoining cells divide to produce a normal-sized trait, even when the injured disc is placed outside of the environment of the developing larva." http://www.pnas.org/content/95/7/3685.full View in LinkedIn

"THE PRINCIPLE OF ALLOCATION is a basic concept in ecology. The principle of allocation also underlies some aspects of the concept of tradeoffs and typically is considered in terms of energy. As a result, organisms tend to be unable to be simultaneously exceptionally durable, such as in terms of maintaining homeostasis, and at the same time exceptionally fecund, at least in terms of a limited resource budget." https://lnkd.in/dSYMHu9 View in LinkedIn

TRAIT SIZE REGULATION. "The findings we describe bear on an old and still unanswered question in biology, namely, how the absolute and relative sizes of traits are regulated. Numerous experiments on regeneration and transplantation have shown that the final size of appendages and internal organs is regulated autonomously, within the structure itself; size regulation of body parts typically requires no external control." http://www.pnas.org/content/95/7/3685.full View in LinkedIn

TOUGH OLD IDEA. "The concept that, during development, different parts of an organism could be in competition with each other is old, and intuitive, but has proven difficult to demonstrate in practice. One reason for this difficulty may be that resource allocation tradeoffs are difficult to measure in organisms that grow and feed continuously, because changes in demands on developmental resources can be met by changes in resource acquisition." View in LinkedIn

RELATIVE GROWTH. "When a limiting resource is shared among several body parts, the degree to which it is used by one part diminishes its availability to another. Such a resource could then constitute a signaling mechanism that controls the relative growth of body parts." http://www.pnas.org/content/95/7/3685.full View in LinkedIn

FRAGMENT FROM NATURE deals with the issue of competition for resources between cells and organs of the same organism, and how resources are allocated between competing interests. This perspective of multicellular creatures being a community of cells turns our world view upside down, but at the same time makes perfect sense. It is the microcosm of natural selection and the survival of the fittest, with the overlay of the priority for the survival of the organism as a surrogate for the survival of the population. View in LinkedIn

TRAIT ALLOCATION. "Competition among body parts in the development and evolution of insect morphology. We show in two very different systems, butterfly wings and beetle horns, that experimentally induced changes in the allocation of developmental resources to one trait produces compensatory changes in the relative sizes of other traits." https://lnkd.in/dk8W49b View in LinkedIn

EU member states to vote on near-total neonicotinoids ban http://www.bbc.co.uk/news/science-environment-43910536 View in LinkedIn