Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5

Evolution: why it seems to have a direction & what to expect next

#1
C C Offline
https://theconversation.com/evolution-wh...ext-139706

EXCERPTS: . . . So natural selection operates from one generation to the next. It cannot plan ahead or have a goal. In addition, not all evolutionary change is a response to selection, but can be neutral or random. It is not even guaranteed to produce more species, since evolution can occur in a single lineage and this can go extinct at any time. How can we reconcile such an aimless process with the bewildering diversity and complexity we see?

Ecology and evolution are two sides of the same coin. The environment is not just the physical surroundings of an organism, but also the other biological species with which it interacts. We can see this environmental interaction deep in the history of life. For billions of years, organisms were “stuck” as single cells within the seas. Several groups independently evolved multi-cellularity (perhaps 25 times). But the first animals, plants and fungi with complex development, different tissues and organs only appeared around 540 million years ago, with the Cambrian “explosion” of diversity.

[...] Once animals had attained greater size and evolved guts, hard parts, jaws, teeth, eyes and legs, complex food webs became possible – along with “arms races” between predators and prey. Groups with adaptations that enabled them to live on land opened up even more opportunities. Once out of the bag, these innovations were difficult to “uninvent” – promoting diversity. ... as we can tell, the species count has been increasing for most of the last 250 million years. Even past natural mass extinctions were only temporary setbacks that may have created even more opportunities for diversity in the long run.

As organisms evolve more complicated systems of development, they may, however, become less able to modify certain aspects of their anatomy. This is partly because genes, tissues and organs often have several different functions, so it may become difficult to change one for the better without accidentally “breaking” something elsewhere.

[...] Clearly, there is an apparent contradiction at the heart of evolutionary biology. On one hand, the mechanisms of evolution have no predisposition for change in any particular direction. On the other hand, let those mechanisms get going, and beyond some threshold, the interwoven ecological and developmental systems they generate tend to yield more and more species with greater maximum complexity... (MORE - details)
Reply
#2
Zinjanthropos Offline
(Jun 3, 2020 04:10 PM)C C Wrote: As organisms evolve more complicated systems of development, they may, however, become less able to modify certain aspects of their anatomy. This is partly because genes, tissues and organs often have several different functions, so it may become difficult to change one for the better without accidentally “breaking” something elsewhere.
 
How complicated is a coelacanth? Hasn’t changed much in 25 million years. 

Do people still believe palaeontologists have unearthed fossils of every creature that ever lived with complete family trees? Billions of years for billions of animals is a long time folks. Unfortunately the fossil record isn’t as grand as some think. Consists mainly of snapshots which is basically what we see with today’s life forms.
Reply


Possibly Related Threads…
Thread Author Replies Views Last Post
  Brainless single-cell seems able to "change its mind" + How microbiomes affect fear C C 2 345 Dec 9, 2019 11:12 PM
Last Post: confused2
  Convergent evolution? Vampire birds have same gut bacteria as vampire bats C C 0 375 Jun 11, 2019 09:16 PM
Last Post: C C
  Next gen weapons against resistant superbugs + Evolution & arthritis risk C C 0 352 Jul 3, 2017 06:09 PM
Last Post: C C



Users browsing this thread: 1 Guest(s)