Sexual and asexual reproduction | Middle school biology | Khan Academy

The planet we live on is full of life and has been for billions of years. Living things on Earth have existed for as long as they have because life found a way to create life. Sounds crazy, right? To put it another way, living things found ways to reproduce, creating offspring that can then go on to reproduce themselves.

But what exactly is reproduction? Well, reproduction is the process of making new organisms. This happens when parent organisms reproduce to form offspring. During reproduction, organisms pass their genetic information onto their offspring. This genetic information provides blueprints for how the offspring will grow and develop and is how traits get passed on from one generation to the next.

There are two main ways organisms on Earth reproduce. This is through asexual reproduction or sexual reproduction. Let's start off by breaking down asexual reproduction first. In asexual reproduction, only one parent is involved in producing offspring. Due to this, the offspring will inherit all of their genes from that single parent. This means that asexual reproduction produces offspring that are genetically identical to their parent. Or in other words, they have the same collection of genes.

Various kinds of microorganisms, plants, and even animals are able to reproduce asexually. An example of asexual reproduction in microorganisms can be seen in bacteria. This is due to their use of a specific type of asexual reproduction called binary fission. During this process, a single bacterial cell grows, copies its genes, and divides into two identical cells—kind of like a copy machine.

Plants are able to reproduce asexually too. For example, some plants grow their offspring off of themselves. In fact, in many succulents, you can see baby plants growing off of their parent plant. These babies have the same genes as their parent plant and can grow on their own if you remove them and plant them in soil.

Finally, and interestingly, there are various animals that can reproduce asexually. One example is seen in starfish or sea stars. Some species of starfish can split into multiple parts that then grow into new starfish. And since they have the same genes, each new starfish is a clone of its original.

Now that we've covered asexual reproduction, let's move on to sexual reproduction. Unlike asexual reproduction, sexual reproduction involves two parents producing an offspring together instead of one. This is important because it means that the offspring will inherit half of their genes from one parent and half of their genes from the other.

Because of this, sexual reproduction produces offspring that are genetically distinct or have a different combination of genes compared to either parent. With this, because of the way the genes are passed on, there are tons of different combinations of genes that can be received from the two parents. In other words, this means that sexual reproduction creates offspring that show a lot of genetic variation between their siblings.

To better understand this, let's take a look at my own dogs. They're brother and sister, so they share the same parents, which I've drawn here. As you've probably noticed, my dogs look pretty different from each other. One of the most notable differences, though, is how one of them received genes from this parent that gave them markings above their eyes that kind of look like eyebrows, while the other did not.

And while it's easy to spot genetic differences like my dog's eyebrows, genetic variation goes way deeper than a dog's fur. It's what makes sexually reproduced organisms genetically distinct from each other and gives the building blocks to who they are.

And with that, you now know the difference between asexual and sexual reproduction. Let's do a quick overview of what you've learned today. Living organisms reproduce to create offspring through either asexual or sexual reproduction. Asexual reproduction involves only one parent, meaning the parent and offspring will have identical genes.

Sexual reproduction involves two parents and results in offspring that are genetically unique compared to either parent. And this all goes to show how fantastically unique life on Earth is. Though organisms may differ in the ways that they've been able to reproduce, as seen in the examples between bacteria, succulents, starfish, and dogs, these organisms, as with all living things, share the ability to create more life, just as all life has shared for billions of years here on this planet.