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NOVA Labs
Course: NOVA Labs > Unit 1
Lesson 1: Evolution 101Evolution 101
Every creature that’s ever lived, including you, has been honed by the powerful force of evolution. Play NOVA's Evolution Lab to learn how it’s responsible for the explosion of Earth's biodiversity. http://www.pbs.org/nova/labs/lab/evolution/ .
Want to join the conversation?
- How did LUCA cells exist in the first place?(3 votes)
- Why were there dinosaurs?(3 votes)
- Well, that's a hard question. Some people (based on religion) would think that they were the first beings made to see if Earth could contain life. But, based on scientific terms, they were what first evolved from the cells, and evolved from their to live longer, successfully reproduce, and to live in different ecosystems.(1 vote)
- can you make captions color to yellow or any other color to be readable because white color in this video not looking good(2 votes)
- I don’t think it’s possible to do that.(1 vote)
- How did evolution over billions of years make us who we are today?(1 vote)
- Over millions of years, organisms slowly adapted to their environment, helping them to produce offspring that were adapted to their environment just like their parents were. As many years went by, the organisms started to expand over to new areas, becoming even more adapted to their environment, forming what they are in the modern day. This is the same with us humans. We basically started out as tiny organisms waiting to develop. Over the years we have become smarter and modernized, until we finally become what we are.(3 votes)
- Is evolution proven to be a fact or is it a mere theory?(2 votes)
- So we are related to cavemen?(1 vote)
- Technically, we are. Cavemen is a broad term. You could be talking about any cavemen, neanderthals or humans. We are related to some neanderthals, but there were cavemen that were humans - and we are definitely related to them.(2 votes)
- when it comes to evolution is it a mathematical or scientific concept?(1 vote)
- It is mathematical and scientific as there are many ratios involved and the science of evolving into another subspecies is scientific because of cell division and the whatnot.(1 vote)
- I have some question on the theory of Evolution when it comes to human evolved from apes. If that is true, then:
1- Why there are still apes?
2- Why there is nothing is the middle? because evolution is gradual we should have half human and half apes beings.
3- Why the evolution stopped at human?
4- If we can say apes evolved into human then there can also be reverse causality meaning that human evolved into apes?
5- Why only apes managed to evolve into a creature (human) that can think, talk, do anything he want, invent and finally dominate the whole world? Why the other failed?
6- If the evolution is true? then how the first cell existed? who created that cell at the first cell?
7- If the evolution is true, what are the scientific evidence? and why it is still called a theory?
I would appreciate if someone could respond to the above questions.(1 vote) - how can we prove that evolution is real(0 votes)
- A proof is a mathematical concept, not a scientific one. Science either disproves ideas, or builds confidence and refines concepts using evidence and observations.
That said, evolution has among the highest degrees of confidence of all scientific concepts.(1 vote)
- Then what began evolution, what stated trees and dogs and pets and so on what really started it?(0 votes)
Video transcript
Ok, go to the window. Or better yet, step
outside. A squirrel darts past. Trees and weeds surge up towards the sky. Birds tickle
the air. Get down on the ground and there’s more—worms wriggling, mushrooms sprouting,
beetles crawling. There’s stuff you can’t even see, like bacteria. And everywhere you
go on this planet—on land, underground, in the air, and in the water—there’s more
life to be found. And all of it—even you—is shaped by the
most incredible of forces. Evolution. Evolution essentially multiplies majesty by
majesty by majesty. And our understanding of all that majesty—it
goes back to the mid-1800s, when an English 20-something, a guy named Charles Darwin,
got an invitation he couldn’t refuse. To travel ’round the world. It was 5 years.
And that voyage made him into a thinker. He was just a great naturalist—he saw things
out in nature, and he asked: “Why?” As in, why is there such a stunning diversity
of life? Why are similar looking species sometimes located on opposite sides of the planet? It was Darwin and Alfred Russel Wallace who
independently puzzled out a mechanism behind evolution. Which was natural selection. Natural selection just means that nature—the
natural environment—is what’s selecting which organisms survive long enough to reproduce.
And it depends on two key ingredients. The first is some way of getting features,
or traits, to be inherited from one generation to the next, which usually means reproduction. The second is variation. If organisms were
to make exact duplicates of themselves every time they reproduced, nothing would change.
There’d be no elephants, no pine trees, no humans – we’d still just be single-celled
proto-organisms. Now, the environment can’t support every
individual that’s born. Maybe it’s too dry or too wet for some of them, maybe all
the food’s up in tall trees, maybe there’s not enough food, or maybe it’s just really
cold. Whatever it is, organisms compete for resources. And this is where selection comes
in. For instance, scientists believe that a few
hundred thousand years ago, before there were polar bears, some brown bears got stranded
in the Arctic. The few that survived likely had fur coats that were a bit thicker, and
lighter in color than the others. That would’ve kept them warmer, and helped them blend in
with the snow to sneak up on prey more easily. The point is—not all variations make it. And the things that survive go on to reproduce. In other words, survival of the fittest. Which
doesn’t necessarily mean the biggest or the strongest. Fittest in an evolutionary sense is whoever
has the most descendants. In the Arctic, the bears with thicker and
whiter coats survived more often and had more offspring—offspring that inherited the thicker
and whiter fur. And gradually, other changes accumulated too. Until this population became
a separate species from the brown bears. However, if we were to swap out the snow for
a forest, having polar bear-like fur would likely be a bad thing. In other words, evolution doesn’t progress
in one fixed direction—but it’s not entirely random either. With so many environments selecting
for all kinds of traits, evolution has resulted in the countless species that have lived on
Earth. Now, Darwin wrote these ideas down. He was not a visual man. So when he did bother to draw something, people
took notice. Like this image he sketched in one of his notebooks. It’s a tree. And it tells us how things are related. That
is, they all can be traced back to a common ancestor. That ancestor—the first living organism
on our planet – is at the base of the tree trunk. Here’s another view of this so-called
phylogenetic tree. As life’s evolved over the last 3.8 billion years, new species have
branched off, leading to entire lineages of different organisms. Every branching point in that tree is a story. Stories of global domination, of extinction.
Stories of beauty, and of remarkable adaptation to an ever-changing world. I mean, the goal of the tree of life is: try
to understand how every species is related to each other. The breadth of this—that
is amazing. And that’s where you come in. In NOVA’s
Evolution Lab, you’ll be climbing around the tree of life to build out portions of
that tree. To see how evolution really works, and understand why it matters to you. Like:
did you eat a dinosaur last night for dinner? Can you save someone from a venomous snakebite?
Or do you have a Neanderthal ancestor? Play this Lab, build the tree of life—which
is your family tree, and discover just how connected you are to everything that’s alive
and everything that’s ever lived.