Welcome to this lesson from the unit Reproduction in humans.

The title of today's lesson is Puberty in humans and sexual maturity.

And what we're going to be looking at today is what puberty is and when it happens, what the purpose of puberty is, and what changes that take place during that process.

My name Mrs. Barnard, and I'm going to be taking you through today's lesson.

So by the end of today's lesson, you should be able to describe the changes that take place in human females and males during puberty, and why these changes are necessary.

So we've got some keywords for you to look out for today, just a few in today's lesson: reproduction, puberty, and hormones.

So I'm gonna put the definitions up.

Now you can just pause the video to write these down, but otherwise we're gonna be going through them at different points during today's lesson.

Okay, so our lesson today is in three parts, and that is puberty, so we're going to be looking at what that is, what the definition of it is and when it happens.

Then we're gonna be looking at preparing for reproduction.

So how those changes allow reproduction then to take place in adults.

And finally, other changes that take place during puberty that aren't necessarily directly related to reproduction.

So let's get started with the first section of today's lesson, which is puberty.

So all living organisms are able to reproduce to make offspring.

So reproduction is one of the common processes of all living organisms. It's a really important process because it allows a species to continue, and it does this by allowing it to make the next generation.

In order for organisms to be able to reproduce, they must have have to have some form of reproductive system.

So some organs in their bodies sole function is about reproducing and making offspring.

So here are the reproductive organs of humans.

So we've got the female reproductive organs and the male reproductive organs, and both of those organ systems work together in order to produce offspring.

So we get a little baby there, and that's the offspring of those parents.

So human children cannot produce offspring because their reproductive systems are not mature.

So as a child develops into an adult, they experience changes, and those changes are physical or emotional.

So they are changes that are in their appearance, so things that you can see, but also emotional changes, which are to do with how you think and how you feel.

And those changes allow the body to then be prepared to reproduce, to produce offspring, and they change a child into an adult.

And the process of these changes is called puberty.

So puberty varies from individual to individual when it starts and when it ends, but there's some ranges in which most individuals would fall.

So for most females, they undergo puberty between the ages of 8 and 14.

So that's when they start.

And generally they finish puberty within four years of when they've started.

So you can see puberty here taking you from a child to an adult in females.

But for males they start slightly later.

Again, it's a range.

So between 9 and 14 years old, and it takes a little bit longer to complete puberty in males.

So it's up to six years.

And again, that takes a child, a boy, into a man through puberty.

So puberty is a stage in the lifecycle of humans.

So as we've gone through a few keywords in those first few slides, what I'd like you to do is to match the keywords to the correct definition.

So pause the video for five seconds while you decide what the correct definition is for reproduction, puberty, and adult.

Okay, so let's see how you got on with that.

So, reproduction.

So reproduction is the process of making offspring.

So it's one of those common processes of living organisms. Puberty is the process of physical changes, also emotional changes that take place when a child becomes an adult.

And the definition of an adult in this context is an organism that is able to reproduce.

Now there's gonna be lots of variation in terms of what somebody might define an adult to be, but in the context of this lesson, it's an organism that can reproduce.

So let's have a little practise task.

So Laura and Sofia here are discussing the process of puberty, and Laura says, "Puberty is an important part of the human lifecycle." And Sofia says, "Puberty changes children into adults." And in this case, both of the pupils do have the correct understanding.

But what I would like you to do is to write an explanation for the importance of puberty.

But you can start by including Laura and Sofia's ideas, because those are correct.

But in your explanation, can you make sure that you use the words puberty, reproduction, and offspring? So if you pause the video while you do this piece of extended writing, and then we'll come back and we will check your answers.

Okay, so let's see how you got on with this.

So Laura said, "Puberty is an important part of the human lifecycle." And Sofia said, "Puberty changes children into adults." So a good explanation would include the following ideas.

So puberty is an important part of the human lifecycle.

It starts in childhood and is completed at the start of adulthood.

The process causes changes that make reproduction possible.

And an adult is a human who is able to reproduce to make offspring.

Now, you may have included some other ideas in there that are also correct.

This is an example of what a good explanation might look like.

Okay, so let's move on to the next part of our lesson.

And the next part of our lesson is preparing for reproduction.

So the changes that we talked about in the previous slides, the physical changes and the emotional changes have to be controlled in the body.

And they are controlled by chemical messengers called hormones.

Now, there's lots of different processes in the body that are controlled by hormones, but the ones that are involved in puberty are called the sex hormones.

Now, you can see in the pictures below that we've got the outline of a male and a female, and there's some coloured shapes highlighted.

Now, those coloured shapes are glands.

Now, the major glands there are indicated, and you can see they're quite similar between a male and a female, and glands release hormones.

The ones that we are interested in though for this lesson is the ones that produce the sex hormones.

So in a female human, we've got ovaries.

So the ovaries release the sex hormones for females.

And in males we've got the testes.

So they are glands that release the sex hormones in males.

So these changes that take place during puberty are there to prepare the body for reproduction and adulthood.

So in order that these humans can produce offspring.

So let's have a look at some of the physical changes that take place.

So in a male reproductive system, so this is a side on view.

So the ones that we've looked at in the previous slides are front on.

This is side on.

One of the things that happens is that the testes and the penis get bigger.

The other thing that happens is that the testes start to produce sperm cells.

In the female reproductive system, the ovaries start to release egg cells and the menstrual cycle begins.

Now, we'll do the menstrual cycle in more detail in another lesson, but the menstrual cycle is a roughly a monthly cycle of events which prepares the female reproductive system for pregnancy.

It's also how you have your period, as you might have heard it, it's part of that menstrual cycle.

So time for a quick check.

So we've got a statement here and want you to decide whether it is true or false.

And once you've decided, there's a couple of statements below.

Which one of those best justifies your answer? So male reproductive organs change in puberty, but female reproductive organs remain the same.

Is that true or false? And would you justify that with a male's testes and penis get bigger, or a male's testes produce sperm and a female's ovaries start to release eggs.

So pause the video while you decide and then we will come back and check on your answer.

Okay, let's see how you got on with this.

So male reproductive organs change in puberty, female reproductive organs remain the same.

That is false.

And the justification for that being false is because the male's testes produce sperm and the female's ovaries start to release eggs.

Sometimes people don't understand that because you can't necessarily see what's happening inside a female, but changes are taking place.

So let's do a quick practise task.

So we've got our pictures again of our male and female reproductive organs.

And what I would like you to do is use the information that you've learned on the previous slides and to label these diagrams with where the hormones are released and also the changes that take place.

So pause the video while you do that and then we'll check back to see how you've got on.

Okay, let's see how you got on with that then.

So first of all, we'll start with the male reproductive system.

So first of all, make sure you've labelled it as the male reproductive system.

And then we are gonna say that the testes get bigger and they release the hormones.

Also, the penis gets bigger.

And finally, the testes produce sperm.

So now we're going to label our female reproductive system.

And first of all, we've got the ovaries release hormones, and then we've got that the ovaries start to release eggs.

And finally, we've got that the menstrual cycle begins.

So if you've got all of those correct, well done.

If not, then add a few extra labels onto your diagram before we move on.

So now it's time for us to do the third part of our lesson today, which is other changes that take place during puberty.

So during puberty, there are also some other changes that take place in order to allow a child to develop into an adult.

Now these changes are both physical and emotional, and in the case of this slide, these detail the changes that take place to both males and females.

So these changes include emotional changes.

So that's changes in the way that we think, the way that we feel, and possibly the way that we act.

Our growth rate increases.

So we get much taller much quicker.

There's a stronger body odour, so a smell that's given off.

The underarm hair grows and also pubic hair grows.

You can see that where the underarm hair and the pubic hair grows is detailed on that diagram there.

So those are the changes that take place for both males and females.

But let's now have a look at the changes that take place only in males.

So first of all, their voice breaks and gets deeper, so much deeper voice.

Sometimes there's a transition phase where sometimes it's a little bit higher and sometimes it's a little bit lower.

And hair starts to grow on the chest and then towards the end of puberty, also on the face.

Also, the shoulders start to get wider as muscle mass increases in males.

So moving on now to the changes that take place for a female.

So the following are the additional changes that happen in females during puberty.

So for females, their breasts develop and also their hips widen.

So that's to prepare those hips for childbirth, that's why they widen.

So let's have a quick check now.

So which of the changes listed below don't happen to either boys or girls? So they're not changes that take place at all.

So pause the video while you decide and then we'll come back and check on your answer.

Okay, so did you choose the right one? It's voice gets higher.

So neither males or females' voice gets higher during puberty.

So let's have another check.

So what I'd like you to do is identify the changes that happen in both males and females during puberty.

So from the ones that are indicated, which ones happen to both? Okay, pause the video while you decide.

The correct answer is that underarm and pubic hair grows.

So that happens to both.

And also emotional changes happen to both.

So let's move on to a practise task now.

So we've got some pupils here and they're discussing the changes that take place in males and females during puberty.

So Izzy says, "Males and females both have physical changes, some of which are to prepare for reproduction." And Jacob says, "During puberty, the changes to males and females' bodies are all to prepare for reproduction." And Alex says, "Females and males both have physical changes, but only males have changes to their reproductive organs, as they get bigger." So what I would like you to do, you have to read through those again, but decide which of the pupils has the most accurate understanding of puberty.

And secondly, can you expand on their statements to give a more complete description of the changes? So all of the changes that take place during puberty that you've learned about in today's lesson.

So pause the video while you complete this because this'll take a little bit of time, and then we'll come back and we'll see how you've got on after.

Okay then, let's see how you got on.

So which of the pupils has the most accurate understanding of puberty? And the answer in this case was Izzy.

And then what we would like you to do is to expand on the statement that they gave, giving a more complete description of the changes that were made.

So this would be a good answer that includes everything.

So see how much matches up to your answer.

So males have an increase in penis and testes size, and they produce sperm to prepare for reproduction.

And males' shoulders widen and voices deepen and they grow facial and chest hair.

Females start to release eggs to prepare for reproduction.

Also, their hips widen and their breasts develop.

And both males and females grow underarm and pubic hair and they have an increase in body odour, they grow quickly, and they go through emotional changes.

There's quite a lot to write about there.

So hopefully you managed to get most of those in your answer, and if you did, then well done.

So that brings us to the end of today's lesson, which was Puberty in humans and sexual maturity.

So our summary is as follows.

Puberty in humans is a term for the changes that the male and female bodies undergo between childhood and adulthood.

The reproductive systems mature to enable adult humans to reproduce.

Other changes also occur which prepare the body for reproduction.

The changes happen because of sex hormones being produced.

These are chemical messengers that are released by the testes and the ovaries.

Females and males undergo some common changes during puberty, but also changes that are just specific to each sex, male or female.

So well done today on your work in today's lesson, and we'll see you again soon.