Science : Evidence for evolution

Evidence for evolution

Key points:

Evidence for evolution comes from many different areas of biology:

Anatomy. Species may share similar physical features because the feature was present in a common ancestor (homologous structures).

Molecular biology. DNA and the genetic code reflect the shared ancestry of life. DNA comparisons can show how related species are.

Biogeography. The global distribution of organisms and the unique features of island species reflect evolution and geological change.

Fossils. Fossils document the existence of now-extinct past species that are related to present-day species.

Direct observation. We can directly observe small-scale evolution in organisms with short lifecycles (e.g., pesticide-resistant insects).


Introduction

Evolution is a key unifying principle in biology. As Theodosius Dobzhansky once said, “Nothing in biology makes sense except in the light of evolution.

But what, exactly, are the features of biology that make more sense through the lens of evolution? To put it another way, what are the indications or traces that show evolution has taken place in the past and is still happening today?


Evolution happens on large and small scales

Before we look at the evidence, let's make sure we are on the same page about what evolution is. Broadly speaking, evolution is a change in the genetic makeup (and often, the heritable features) of a population over time. Biologists sometimes define two types of evolution based on scale:

Macroevolution, which refers to large-scale changes that occur over extended time periods, such as the formation of new species and groups.

Microevolution, which refers to small-scale changes that affect just one or a few genes and happen in populations over shorter timescales.

Microevolution and macroevolution aren’t really two different processes. They’re the same process – evolution – occurring on different timescales. Microevolutionary processes occurring over thousands or millions of years can add up to large-scale changes that define new species or groups.


The evidence for evolution
In this article, we'll examine the evidence for evolution on both macro and micro scales.

First, we'll look at several types of evidence (including physical and molecular features, geographical information, and fossils) that provide evidence for, and can allow us to reconstruct, macroevolutionary events.

At the end of the article, we'll finish by seeing how microevolution can be directly observed, as in the emergence of pesticide-resistant insects.


Anatomy and embryology

Darwin thought of evolution as "descent with modification," a process in which species change and give rise to new species over many generations. He proposed that the evolutionary history of life forms a branching tree with many levels, in which all species can be traced back to an ancient common ancestor.



In this tree model, more closely related groups of species have more recent common ancestors, and each group will tend to share features that were present in its last common ancestor. We can use this idea to "work backwards" and figure out how organisms are related based on their shared features.


Homologous features

If two or more species share a unique physical feature, such as a complex bone structure or a body plan, they may all have inherited this feature from a common ancestor. Physical features shared due to evolutionary history (a common ancestor) are said to be homologous.

To give one classic example, the forelimbs of whales, humans, birds, and dogs look pretty different on the outside. That's because they're adapted to function in different environments. However, if you look at the bone structure of the forelimbs, you'll find that the pattern of bones is very similar across species. It's unlikely that such similar structures would have evolved independently in each species, and more likely that the basic layout of bones was already present in a common ancestor of whales, humans, dogs, and birds.



Some homologous structures can be seen only in embryos. For instance, all vertebrate embryos (including humans) have gill slits and a tail during early development. The developmental patterns of these species become more different later on (which is why your embryonic tail is now your tailbone, and your gill slits have turned into your jaw and inner ear). Homologous embryonic structures reflect that the developmental programs of vertebrates are variations on a similar plan that existed in their last common ancestor.



Sometimes, organisms have structures that are homologous to important structures in other organisms but that have lost their major ancestral function. These structures, which are often reduced in size, are known as vestigial structures. Examples of vestigial structures include the tailbone of humans (a vestigial tail), the hind leg bones of whales, and the underdeveloped legs found in some snakes.

Analogous features

To make things a little more interesting and complicated, not all physical features that look alike are marks of common ancestry. Instead, some physical similarities are analogous: they evolved independently in different organisms because the organisms lived in similar environments or experienced similar selective pressures. This process is called convergent evolution. (To converge means to come together, like two lines meeting at a point.)

For example, two distantly related species that live in the Arctic, the arctic fox and the ptarmigan (a bird), both undergo seasonal changes of color from dark to snowy white. This shared feature doesn’t reflect common ancestry – i.e., it's unlikely that the last common ancestor of the fox and ptarmigan changed color with the seasons. Instead, this feature was favored separately in both species due to similar selective pressures. That is, the genetically determined ability to switch to light coloration in winter helped both foxes and ptarmigans survive and reproduce in a place with snowy winters and sharp-eyed predators.



Determining relationships from similar features

In general, biologists don't draw conclusions about how species are related on the basis of any single feature they think is homologous. Instead, they study a large collection of features (often, both physical features and DNA sequences) and draw conclusions about relatedness based on these features as a group. We will explore this idea further when we examine phylogenetic trees.

Molecular biology

Like structural homologies, similarities between biological molecules can reflect shared evolutionary ancestry. At the most basic level, all living organisms share:

The same genetic material (DNA)
The same, or highly similar, genetic codes
The same basic process of gene expression (transcription and translation)
The same molecular building blocks, such as amino acids

These shared features suggest that all living things are descended from a common ancestor, and that this ancestor had DNA as its genetic material, used the genetic code, and expressed its genes by transcription and translation. Present-day organisms all share these features because they were "inherited" from the ancestor (and because any big changes in this basic machinery would have broken the basic functionality of cells).

Although they're great for establishing the common origins of life, features like having DNA or carrying out transcription and translation are not so useful for figuring out how related particular organisms are. If we want to determine which organisms in a group are most closely related, we need to use different types of molecular features, such as the nucleotide sequences of genes.

Homologous genes

Biologists often compare the sequences of related genes found in different species (often called homologous or orthologous genes) to figure out how those species are evolutionarily related to one another.

The basic idea behind this approach is that two species have the "same" gene because they inherited it from a common ancestor. For instance, humans, cows, chickens, and chimpanzees all have a gene that encodes the hormone insulin, because this gene was already present in their last common ancestor.

In general, the more DNA differences in homologous genes (or amino acid differences in the proteins they encode) between two species, the more distantly the species are related. For instance, human and chimpanzee insulin proteins are much more similar (about 98% identical) than human and chicken insulin proteins (about 64% identical), reflecting that humans and chimpanzees are more closely related than humans and chickens.

Biogeography

The geographic distribution of organisms on Earth follows patterns that are best explained by evolution, in combination with the movement of tectonic plates over geological time. For example, broad groupings of organisms that had already evolved before the breakup of the supercontinent Pangaea (about 200200200 million years ago) tend to be distributed worldwide. In contrast, broad groupings that evolved after the breakup tend to appear uniquely in smaller regions of Earth. For instance, there are unique groups of plants and animals on northern and southern continents that can be traced to the split of Pangaea into two supercontinents (Laurasia in the north, Gondwana in the south).



The evolution of unique species on islands is another example of how evolution and geography intersect. For instance, most of the mammal species in Australia are marsupials (carry young in a pouch), while most mammal species elsewhere in the world are placental (nourish young through a placenta). Australia’s marsupial species are very diverse and fill a wide range of ecological roles. Because Australia was isolated by water for millions of years, these species were able to evolve without competition from (or exchange with) mammal species elsewhere in the world.

The marsupials of Australia, Darwin's finches in the Galápagos, and many species on the Hawaiian Islands are unique to their island settings, but have distant relationships to ancestral species on mainlands. This combination of features reflects the processes by which island species evolve. They often arise from mainland ancestors – for example, when a landmass breaks off or a few individuals are blown off course during a storm – and diverge (become increasingly different) as they adapt in isolation to the island environment.

Fossil record

Fossils are the preserved remains of previously living organisms or their traces, dating from the distant past. The fossil record is not, alas, complete or unbroken: most organisms never fossilize, and even the organisms that do fossilize are rarely found by humans. Nonetheless, the fossils that humans have collected offer unique insights into evolution over long timescales.



How can the age of fossils be determined? First, fossils are often contained in rocks that build up in layers called strata. The strata provide a sort of timeline, with layers near the top being newer and layers near the bottom being older. Fossils found in different strata at the same site can be ordered by their positions, and "reference" strata with unique features can be used to compare the ages of fossils across locations. In addition, scientists can roughly date fossils using radiometric dating, a process that measures the radioactive decay of certain elements.

Fossils document the existence of now-extinct species, showing that different organisms have lived on Earth during different periods of the planet's history. They can also help scientists reconstruct the evolutionary histories of present-day species. For instance, some of the best-studied fossils are of the horse lineage. Using these fossils, scientists have been able to reconstruct a large, branching "family tree" for horses and their now-extinct relatives. Changes in the lineage leading to modern-day horses, such as the reduction of toed feet to hooves, may reflect adaptation to changes in the environment.



Direct observation of microevolution

In some cases, the evidence for evolution is that we can see it taking place around us! Important modern-day examples of evolution include the emergence of drug-resistant bacteria and pesticide-resistant insects.

For example, in the 1950s, there was a worldwide effort to eradicate malaria by eliminating its carriers (certain types of mosquitos). The pesticide DDT was sprayed broadly in areas where the mosquitoes lived, and at first, the DDT was highly effective at killing the mosquitos. However, over time, the DDT became less and less effective, and more and more mosquitoes survived. This was because the mosquito population evolved resistance to the pesticide.



Emergence of DDT resistance is an example of evolution by natural selection. How would natural selection have worked in this case? [More on natural selection]

Before DDT was applied, a tiny fraction of mosquitos in the population would have had naturally occurring gene versions (alleles) that made them resistant to DDT. These versions would have appeared through random mutation, or changes in DNA sequence. Without DDT around, the resistant alleles would not have helped mosquitoes survive or reproduce (and might even have been harmful), so they would have remained rare.

When DDT spraying began, most of the mosquitos would have been killed by the pesticide. Which mosquitos would have survived? For the most part, only the rare individuals that happened to have DDT resistance alleles (and thus survived being sprayed with DDT). These surviving mosquitoes would have been able to reproduce and leave offspring.

Over generations, more and more DDT-resistant mosquitoes would have been born into the population. That's because resistant parents would have been consistently more likely to survive and reproduce than non-resistant parents, and would have passed their DDT resistance alleles (and thus, the capacity to survive DDT) on to their offspring. Eventually, the mosquito populations would have bounced back to high numbers, but would have been composed largely of DDT-resistant individuals.

In parts of the world where DDT has been used extensively in the past, many of the mosquitoes are now resistant. DDT can no longer be used to control the mosquito populations (and reduce malaria) in these regions.

Why are mosquito populations able to evolve rapid resistance to DDT? Two important factors are large population size (making it more likely that some individuals in the population will, by random chance, have mutations that provide resistance) and short lifecycle. Bacteria and viruses, which have even larger population sizes and shorter lifecycles, can evolve resistance to drugs very rapidly, as in antibiotic-resistant bacteria and drug-resistant HIV.

Summary

Multiple types of evidence support the theory of evolution:

Homologous structures provide evidence for common ancestry, while analogous structures show that similar selective pressures can produce similar adaptations (beneficial features).

Similarities and differences among biological molecules (e.g., in the DNA sequence of genes) can be used to determine species' relatedness.

Biogeographical patterns provide clues about how species are related to each other.

The fossil record, though incomplete, provides information about what species existed at particular times of Earth’s history.

Some populations, like those of microbes and some insects, evolve over relatively short time periods and can observed directly.

Re: Evidence for evolution

Evolution is a fact!

Only the stupidest of retards would disagree with that.

We are accountable to reality. To truth and goodness and beauty.

Re: Evidence for evolution

The Russian foxes bred for neotenous/domesticated traits are a good one

"Only the stupidest of retards would disagree with that."
Nullius in Verba

Re: Evidence for evolution

So true.

How Can Mirrors Be Real If Our Eyes Aren't Real

Re: Evidence for evolution

All that mystical mumbo-jumbo that you just posted above still doesn't explain how all that could have happened in mere 6000 years. And that is an indisputable proven fact since we are only able to observe stars and galaxies 6000 light years or closer at this point in time.

Re: Evidence for evolution

When I learned it, immediately I thought this theory of evolution explained all lifeforms on planet Earth except for human beings.

Even after biologists determined that chimpanzees share 98% of the same DNA sequences as humans. We still are greatly different. What compelled the chimpanzees to remain walking upright, lose most of its body hair, learn speech and built is home and all the other things homo sapiens are capable of doing? The had to be a motivation for survival. Chimpanzees and the other great apes survive fine like they are until we destroyed their habitat and even then the great apes are not evolving as quickly as mosquitos, virus, maggots and bacteria.
Why?
Now I'm thinking this:

Could be that all other animals evolved from homo sapiens? We, bacteria, viruses, maggots and those other species that evolve quickly are the first life forms on planet Earth?

Re: Evidence for evolution

From what I’ve gleaned over the years, the theory is about the walking upright part was that it was helpful in the tall grasslands to be able to see any approaching predators more easily, thus enabling them to survive and pass on their traits more frequently than the ones that didn’t go upright as well.

It would be just a guess, but I would imagine that it wasn’t all chimps everywhere that started evolving into more advanced hominids, but probably just a particular group of chimps that encountered some type of selective pressure due to their particular geographic location that other chimps weren’t exposed to that gave them an evolutionary advantage over ordinary chimps. Over the course of thousands or even millions of generations, these differences became more and more pronounced until I was finally born - the pinnacle of evolution thus far.

I am a super-monkey!

Re: Evidence for evolution

From what I’ve gleaned over the years, the theory is about the walking upright part was that it was helpful in the tall grasslands to be able to see any approaching predators more easily, thus enabling them to survive and pass on their traits more frequently than the ones that didn’t go upright as well.
Okay I am relying on information from Google in order to apply the science to the theory.

Who are predators in a grassland habitat?


Predators. Carnivorous predators inhabit grasslands in high numbers. Jaguars, Sumatran and Malayan tigers, lions, leopards, hyenas, cheetahs, African wild dogs, wolves and coyotes all patrol in search of grazing and roaming prey.

These are the species alive today. Early humans did have more hair on their bodies. That would make them blend in. But they also had the ability to craft crude weapons and other useful tools. The first humans probably interbreed when they migrated from Africa.

There's a video pdf
Dr. Rick Potts provides a video short introduction to some of the evidence for human evolution, in the form of fossils and artifacts
https://humanorigins.si.edu/education/introduction-human-evolution

Re: Evidence for evolution

*WHEW!*
You had me going for a minute there bud.
Getting all serious around here like that.
I was about to call the Straight Man Help Hotline on your behalf.
Their motto is, "We take a straight man and help him become gay for your pleasure!"

"Please vote to preserve the unique character of Warren…" - Robert Duvall

Re: Evidence for evolution

What compelled the chimpanzees to remain walking upright, lose most of its body hair, learn speech and built is home and all the other things homo sapiens are capable of doing? The had to be a motivation for survival.

You fundamentally have no idea how evolution works. A species does not will, through motivation, changes to their DNA.

Could be that all other animals evolved from homo sapiens?

No. That's ignorant, batshit crazy lunacy.

The fossil and DNA records are very, very clear on what evolved from what. This is established science and there is no room for such ridiculous speculation.

Re: Evidence for evolution

It's not that I have no idea. It's that I have forgotten.

No. That's ignorant, batshit crazy lunacy.

The fossil and DNA records are very, very clear on what evolved from what. This is established science and there is no room for such ridiculous speculation.

Oh? My courses didn't focus on too much of that. So what evolved from what Mr. Brilliant?

Apes into hairless walking upright humans. Okay well then you're a white ape asshole.

Re: Evidence for evolution

You are feeding a troll who is just here to make up **** for it's grins and gigs.

"Please vote to preserve the unique character of Warren…" - Robert Duvall

Re: Evidence for evolution

And what the **** are you here for? Other than chasing after monicah's ass as she takes classes to be a medical assistant.

Re: Evidence for evolution

Warren is a stupid **** but in this case he is correct. Lyman is one of conmans sock accounts.


Fuck his Mother

Beware the sound of one hand clapping.

Re: Evidence for evolution

I'm gonna put that stupid love letter you wrote to me on Tik Tok so I can laugh at it along with whoever wants a laugh as well.

Re: Evidence for evolution

Go for it then I can see if you really are a tranny or a teenage boy as I suspect.

"Please vote to preserve the unique character of Warren…" - Robert Duvall

Re: Evidence for evolution

no sane person has ever confused me for being a tranny or a teenage boy. It's just stupid you and your stupid friends.

Re: Evidence for evolution

And I'll show people that part you said about me being a tranny and teenage boy too. The routine is unfolding in my mind as I write this. I'll make them laugh at you. Dave Chappelle taught me how to talk to my audience while telling jokes.

Re: Evidence for evolution

Yeah right.
Do it or not I don't give a ****.

"Please vote to preserve the unique character of Warren…" - Robert Duvall

Re: Evidence for evolution

Fine. I'll leave. I'm tired of getting attack about everything. Is that what you want, Romeo?
Writing love letters to women and then throwing her under the bus every other day.

Re: Evidence for evolution

This is conmans thread. Are you sure you want to piss off your benefactor by calling him a liar?

Beware the sound of one hand clapping.

Re: Evidence for evolution

About waterfalls, if creation is true then was some water created in mid fall or was the water held back and didn't fall over the edges of the cliffs until the moment AFTER creation?

I think it was created in mid fall. Likewise some of the starlight was created mid travel. That would actually mean that the light reaching us 'from' some stars was never actually originated at those stars. Kind of wild.

Beware the sound of one hand clapping.

Re: Evidence for evolution



We are accountable to reality. To truth and goodness and beauty.

Re: Evidence for evolution

Yes, the movie exists.

Course, that is as close as it gets conman. Unless you have an answer for why there are no new genes as pointed out in the other post. But you can't. Good luck wasting your time searching for another pithy little meme.

Beware the sound of one hand clapping.

Re: Evidence for evolution



We are accountable to reality. To truth and goodness and beauty.

Re: Evidence for evolution


It quite literally is.
Evolution always comes down to the smallest scale. Even the closest species are separated by thousands of base pairs. Unless evolution has stopped completely, [& if so why?] Then in some species we should see new base pairs being added. Yet this hasn't happened in any of the millions of species known to science. We have seen mutations that transpose and mutations that subtract but nothing that adds.

But you are conman. You will ignore that fact. You will simply continue to insist that you are right and declare victory without actually backing it up. You are a goon-ass twink bastard.













Fuck your Mother

Beware the sound of one hand clapping.

Re: Evidence for evolution



We are accountable to reality. To truth and goodness and beauty.

Re: Evidence for evolution

Now see this is the sort of thing I'm talking about. Goon-ass twink bastard behavior. Rather than address the fact that new base pairs [evolution] has NEVER been observed in any species you slap together some half-ass meme.

Declare victory if you wish but know that you lost. And until you address the base pair issue you will continue to lose.

Beware the sound of one hand clapping.

Re: Evidence for evolution



We are accountable to reality. To truth and goodness and beauty.

Re: Evidence for evolution

until you address the base pair issue you will continue to lose.

Beware the sound of one hand clapping.

Re: Evidence for evolution

Evolution is real.

I won.

We are accountable to reality. To truth and goodness and beauty.

Re: Evidence for evolution

until you address the base pair issue you will continue to lose.

Beware the sound of one hand clapping.

Re: Evidence for evolution

Evolution is real.

You lost.

We are accountable to reality. To truth and goodness and beauty.

Re: Evidence for evolution

You sure showed him. As usual, Loser_Venom had no argument at all.

Re: Evidence for evolution



Just imagine not believing in evolution…

We are accountable to reality. To truth and goodness and beauty.

Re: Evidence for evolution

heres_ky said...

Just imagine not believing in evolution…
expand
What an idiot. LOL!

I've heard he (venom) ****s dogs.

Re: Evidence for evolution

Lyman said... What an idiot. LOL!

I've heard he (venom) fucks dogs.
expand
Yeah. He's known to rape puppies.

We are accountable to reality. To truth and goodness and beauty.

Re: Evidence for evolution

heres_ky said... Yeah. He's known to rape puppies.
expand
Hahaha! No wonder people **** in his mouth.

Re: Evidence for evolution

Lyman said... Hahaha! No wonder people shit in his mouth.
expand


My password is password

Re: Evidence for evolution

Lyman said... Hahaha! No wonder people shit in his mouth.
expand
😲

My password is password

Re: Evidence for evolution

I did this vocaroo for another thread on the same topic this morning 😸



Travel influenser, Skyrizi theme song writer and Most Handsome

Re: Evidence for evolution

That is because this is a conman thread. No doubt created only to oppose my own. It's like wagging the dog around here. I can practically dictate what conman will post on next by posting on the topic myself. If I say black you can count on that goon-ass twink bastard to say white.



Fuck his Mother

Beware the sound of one hand clapping.

Re: Evidence for evolution

News flash.
Not everyone is going to create an OP in response to yours.
Sometimes it is coincidence of things they want to share that is important to them.

OK so if evolution does not exist then how would you explain that the skulls of early humans from thousands of years ago look so much more different than the ones we now have.

Birds evolved from dinosaurs.
Do you deny that fact?

"Please vote to preserve the unique character of Warren…" - Robert Duvall

Re: Evidence for evolution

Not everyone is going to create an OP in response to yours.
This is correct. Conman however is a goon-ass twink bastard and as such it has become a predictable part of his M.O.



Fuck his Mother

look so much
Since life is all based on the same molecule looks mean nothing.

According to preliminary sequences from 2010, 99.7% of the nucleotide sequences of the modern human and Neanderthal genomes are identical, compared to humans sharing around 98.8% of sequences with the chimpanzee
The fact is that so-called 'neanderthals' are close enough genetically to breed with modern humans. The differences at the genetic level could just as easily be explained by inbreeding among a relatively small population causing enough genetic damage to create the 0.2% difference.

Birds evolved from dinosaurs.
Do you deny that fact?
When did you stop beating your wife?
One logical fallacy deserves another. Your logical fallacy is worded to assume a fact that you haven't yet proven to BE a fact.

I personally believe that God created all life using the DNA molecule as a blueprint. He created every variation of that molecule that resulted in a viable lifeform.
This explains why not transitional forms for one species to another exist ANYWHERE in the fossil record.

Beware the sound of one hand clapping.

Re: Evidence for evolution

So the one you are calling "Conman" is "Lyman?"
Socks of each other or name changes?
Or is "Conman" a generic name you are using for those you strongly disagree with?
Have you seen other threads created by Ly/Conman that are a counter point to a post you brought up shortly before?

So do you think or believe that things created by God have the capacity to change through time?

"Please vote to preserve the unique character of Warren…" - Robert Duvall

Re: Evidence for evolution

You are relatively new here so it is understandable that you dont know.

Yes they are one and the same person. Conman is actually slang for Conmander_Jim. He is the biggest worst uber-leftist troll on the board. We went to war a couple years back and one of his tactics was to create over 100+ sock accounts. Another of his tactics was spamming the politics boards then bumping his own posts using short affirming posts from his sock accounts. He is histories one and only goon-ass twink bastard.


Fuck his Mother

There are a handful of people on these boards that I consider stupid and have no use for, yourself included. However none of you are worse than that sorry stupid **** eating, dog ****ing, baby raping son of a retarded disease ridden whore.

Check out this poll. All named candidates are Conman socks. I think you've even tangled with the sorry sack of monkey **** a few times. https://www.filmboards.com/board/t/A-fair,-free,-democratic-election-3366691/

Beware the sound of one hand clapping.

Re: Evidence for evolution



Well I wanted divine intervention, and this is what I got. Thanks.

So, you're blending human evolution with The Book of Genesis. Nice.👍 Solve the missing link found in the logic for God's sakes, man!!

Re: Evidence for evolution

Solve the missing link found in the logic

And which missing link would that be? After the flood the people left were the sons of Shem, Ham, and Japheth. Japheth was the eldest and it is his decendants that would migrate east into asia, and later north and south america. Those of Ham went south into Africa later the south pacific. Shems spread north and west. It would be several generations before there were enough people to mitigate the inbreeding effect. Those are your 'neanderthals'.

Beware the sound of one hand clapping.

Re: Evidence for evolution

And which missing link would that be? After the flood the people left were the sons of Shem, Ham, and Japheth.

There was a flood. Any scientific evidence supporting that biblical story?

Re: Evidence for evolution

Tons. You have to understand that most of the same evidence that is used for evolution can also be used to support Creation. The only difference is in how the evidence is interpreted. The entire fossil record is evidence.

list=PLvTah6tEcChwZjUyG6X_5_zwVDAalSJHI

Beware the sound of one hand clapping.
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