How does evolution takes place? What micro and macro evolution.
Answers
Answer:
Imagine each of these digits is a creature:
1 3 7 8 4 2 1 9 7 2 3 6
Each generation, a creation may or may not give birth by copying itself
1 → 1 1 1
3
7 → 7 7
…
As you can se, the first creature (1) had three children, the second (3) had none, and the third (7) had 2.
Now let’s add another wrinkle: each time a creature reproduces, there’s a small chance its child may be slightly different from it (maybe due to cosmic radiation causing a mutation). Our number children can mutate by being one digit higher or lower than their parents:
1 → 1 2 1
As you can see, 1’s second child mutated to a 2.
Final wrinkle: there’s environmental pressure that favors creatures that are closer to being 5s. So you’re apt to be lucky if you’re born a 4, 5, or 6. You’re apt to be unlucky if you’re a 2 or a 9.
There’s something about being a 5 that helps you get more food, and the more food you have, the easier time you’ll have reproducing. If you spend all your energy searching for food—which is the sad fate for many 1’s, 2’s, 8’s, and 9’s—you’ll have little energy left for reproducing, so you’ll have fewer kids than the 4’s 5’s, and 6’s on average.
Okay, given those rules, let’s see what happens to our original population after they’ve been living for a while:
1 → 1
3 → 3 3 4
7 → 7 7
8
4 → 4 4 5 4 3
2
1
9 → 9
7
2
3 → 3 3
6 → 6 6 6 7 6
Notice that even though 1 is pretty far from 5, the top creature (1) got lucky and had a child anyway, as did a surprisingly lucky 9 lower down. Sometimes that happens. And even though 7 is pretty close to 5, there’s a 7 in the group that got unlucky and had no children. It’d even possible for a 5 to get unlucky and have no children—and for a 9 to get really lucky and have multiple children. But those occurrences are statistically rare.
For the most part, things played out as we’d expect, and the most children were had by 4 and 6. Note that some of their children mutated.
So, now the first generation is dead and our new population (the children) looks like this:
1
3 3 4
7 7
4 4 5 4 3
9
3 3
6 6 6 7 6
One wrinkle I didn’t mention is that the food supply is limited. So the population can’t keep getting bigger and bigger. Eventually, it would run out of food. The existing creatures are all competing for a limited supply—and, as stated above, the ones closest to 5 tend to be the winners.
Here’s the next set of births:
1
3
3 → 3
4 → 4 4 5
7
7 → 7 7
4 → 4
4 → 4 3 4 4 4 4
5 → 5 5 5 5 6 5 5 5 5 5 4
4 → 4 4
3
9
3 → 3
3
6 → 6 6 6 5
6 → 6 6 7 6 6 6 6
6 → 6
7
6 → 6 6 6
What I hope you can see is that, if this keeps happening, the population will become more “fit.” It will converge on 5. Due to mutations (and lucky non-5′s), we’ll never likely get a generation of all 5′s, but the population will be biased in that direction.
Here’s what it might look like after several more generations:
5
5
4
5
5
5
9
6
5
5
5
5
3
5
4
If you want to add another level of complication to this, imagine the environmental forces drifting. Maybe the planet has heated up, which somehow makes 7 a more winning number than 5. Evolution can be a moving target.
There’s tons more we can add to this picture, such as sexual reproduction, sexual selection, genetic drift, epigenetics, and so on, but what we have is sufficient for Evolution to happen. It only requires—
A starting population.
A mechanism for organisms to copy themselves.
Rare mutations that sometimes make copies slightly different than originals.
Outside (environmental) forces that make some mutations more advantageous than others.
Note: “More advantageous” means “that which gives the organism with those mutations a statistically better chance of reproducing.”
If all of those things are in place, Evolution will occur.
Explanation: