The Influence of Climate on the Evolution of Early Humans

Explainer AI

Transcript

00:00It's me, and you are watching this channel.

00:03This is the story of our distant ancestors.

00:06They were probably short, kind of stupid, and really ugly.

00:10Now that's not fair.

00:11We are all beautiful in our own unique way,

00:14and our ancestors are no exception.

00:18But their beauty was a little bit different from ours

00:21because they were covered head to toe in luscious, thick body hair.

00:25But why?

00:26Well, one reason can be found right outside the climate.

00:31You see, the climate during that time was not like now.

00:34Back then, it was much colder,

00:36and humans needed the extra fluffiness to stay warm.

00:40But why are we talking about this now?

00:43Well, recently some scientists discovered evidence

00:46of an ancient mega-drought in East Africa,

00:49which lasted for around 20,000 years.

00:52But when did this happen?

00:53Well, during a period where early humans were evolving into modern humans.

00:59So, could this have affected them?

01:01Well, if they hadn't adapted to the changing climate,

01:05yes, it would have wiped them out.

01:07But that's not what happened, is it?

01:09So, this means that the drying up of the world around them

01:12played a part in our evolution.

01:14But how?

01:15Welcome to my channel.

01:18It's time to find out.

01:20The truth is our fur.

01:22Humans today come in all shapes and sizes.

01:25Our skin comes in a variety of colors,

01:27and our hair comes in all kinds of crazy styles.

01:30There's even a person out there with no hair at all.

01:33But our distant ancestors didn't have the same luxury.

01:37You see, they were all covered head to toe in thick body hair.

01:40But why?

01:42Well, think back to the last time you went swimming in the freezing cold ocean water.

01:47What was the first thing you did afterwards?

01:49Did you go for a nice walk on the beach,

01:51or maybe lie down and soak up some sun?

01:54No, you probably did your best to get warm as fast as possible.

01:58You might have rubbed yourself against a towel

02:00or snuggled up next to your friends to share body heat.

02:03Even animals do this by huddling together.

02:05And humans are animals too, right?

02:09Well, our ancestors were the same.

02:12They huddled together for warmth.

02:14But there was a problem.

02:16Their bodies weren't used to being so close to each other for so long.

02:19See, as a species,

02:21we're not great at regulating our own body temperature.

02:24As a result, humans tend to overheat when we're too close to each other.

02:28And if they couldn't cool themselves down,

02:31they would have died.

02:32So, to avoid this, they started removing some of their hair.

02:36This would have made it more comfortable for them to be around each other.

02:39And if females preferred males with less body hair,

02:43well, that would have been a bonus.

02:45After all, females are usually the ones who choose their partners based on looks.

02:50But our ancestors' need to remove their hair didn't stop there.

02:54As they continued to develop,

02:56their brains got bigger and bigger.

02:59And bigger brains mean more heat.

03:01To compensate for this,

03:03our ancestors lost even more body hair over time until modern humans evolved.

03:09But this wasn't the only thing that happened during this time.

03:13Our ancestors also had to deal with something else.

03:16Change.

03:16As you already know,

03:18the climate changed during the Middle Stone Age,

03:21which began 34,000 years ago,

03:23and lasted until around 12,000 years ago.

03:27During this time, the world slowly became drier.

03:31But you knew that already.

03:33The question is,

03:34how did this affect early humans?

03:37See, humans aren't really good at adapting quickly.

03:40We don't reproduce fast enough to make big changes to our DNA in a short amount of time.

03:46Take polar bears, for example.

03:48They evolved from brown bears only 500,000 years ago.

03:53And since then,

03:54they've developed the perfect adaptations for surviving in the Arctic Circle.

03:59Things like a thick coat of fat and a layer of dense fur.

04:03But humans didn't evolve in such a short time frame.

04:06It took us more than 6 million years to become the species we are today.

04:10But during that time,

04:12we've learned to adapt to the world around us.

04:15And that's exactly what our ancestors did when the climate changed.

04:19Take, for example, the Sahara.

04:22Right now, it's the third biggest desert in the world.

04:25But it wasn't always like this.

04:26In fact, until very recently,

04:29it was full of plants and animals,

04:31including early humans.

04:33But then the climate shifted,

04:34and the Sahara turned into a desert.

04:37So our ancestors migrated southwards into what is now Ethiopia,

04:41where there was plenty of food and water.

04:44But it wasn't all sunshine and rainbows.

04:46Our ancestors had to deal with the problem of food shortage.

04:50And no, this doesn't mean they went hungry.

04:53It just means that the types of food available to them changed.

04:57For example,

04:58wild barley and legumes were replaced by new foods like sorghum and African rice.

05:03Of course, these plants wouldn't have appeared out of nowhere.

05:08Seeds brought by migrating birds would have germinated and grown,

05:11providing food for those who ate them.

05:14And our ancestors were smart enough to realize that if they planted these seeds,

05:18they would grow into food.

05:20And just like that, agriculture was born.

05:24But it wasn't easy.

05:25Farming isn't as simple as putting a seed in the ground and watering it.

05:29First, humans had to learn how to control their environment.

05:33They had to build dams to hold back the water and irrigation ditches to direct it towards their crops.

05:39They also had to develop new tools to help them farm.

05:42And it took a lot of work to keep the pests away.

05:45But as time passed,

05:47farming became easier and more efficient.

05:50In fact,

05:51this period of development is called the Neolithic Revolution.

05:54It began 12,000 years ago,

05:57after the end of the last ice age.

06:00And it changed the world forever.

06:03Farming allowed humans to settle down in one place

06:05instead of wandering around as nomads.

06:08It also led to population growth,

06:11specialization of labor and the formation of cities,

06:14which led to the development of civilizations.

06:16But farming wasn't the only change that occurred in East Africa during the Middle Stone Age.

06:22Something else happened.

06:24Language.

06:25Scientists have discovered that the oldest known human ancestor capable of speech lived in this region.

06:31And the oldest evidence of this ability dates back 190,000 years.

06:37But how do scientists know that it was our ancestor?

06:40Well, it's thanks to a small hole in its skull.

06:43You see, when humans speak, we use our tongues to form words.

06:48To do this, we move our tongues all around our mouths,

06:51and this requires a large opening between our mouth and nose.

06:55Other animals can't talk because their skulls are too small or their tongues are too thin.

07:01But our ancestors were different.

07:03They had the ability to speak, which gave them an advantage over other species.

07:08Language allowed humans to communicate more effectively,

07:11which helped them cooperate, plan for the future, and pass on knowledge to younger generations.

07:17This is one of the reasons why humans became the dominant species on Earth.

07:22But this isn't the only reason.

07:24Another major factor in our success is our adaptability.

07:28You see, humans can adapt to almost any environment on Earth.

07:32We can survive in hot deserts, frozen tundras, and everything in between.

07:37But sometimes this adaptability can be a bad thing.

07:41You see, when the climate began to change during the Middle Stone Age,

07:45many species couldn't adapt quickly enough and went extinct.

07:49But humans were able to adapt and thrive.

07:52In fact, scientists believe that this is the reason why only one species of the genus Homo remains,

07:58while all the others died out.

08:00The truth is, humans are a pretty adaptable bunch.

08:04We're not the strongest or fastest.

08:06But we're pretty clever.

08:08And our adaptability has allowed us to thrive in almost every environment on Earth.

08:13So the next time you hear someone say that humans are the dominant species on Earth,

08:18remember that it wasn't easy to get here.

08:20It took millions of years of adapting and evolving to reach this point.

08:24And who knows what the future holds.

08:27Maybe one day we will evolve to have green fur.

08:30But until then, we will continue to adapt and evolve as a species.

08:35That is if we don't wipe ourselves out first.

08:39Now you need to watch how humans will evolve or die trying.

08:42Or check out this video instead.

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