Reproduction is how organisms pass on their genes. While some organisms reproduce only sexually or asexually, there are many that do both. This lesson will explore the benefits of this strategy and some examples of the organisms that employ it.
If you take a look around, you’ll notice there are many kinds of living organisms. The many plants and animals in nature that look, sound, and act differently. But one thing they have in common is the need to reproduce, or create a new generation of offspring.
Each plant and animal that you see has a specific life span; it can only live for so long. To pass on its genetic material, it creates new individuals through reproduction.
Two Types of Reproduction
Before we go any further, we need to understand the two types of reproduction that occur in living organisms. First is asexual reproduction, or reproduction without sex (a means without).
In asexual reproduction, the offspring are genetically identical to the parent. There are many modes of asexual reproduction including budding (a new individual splits off from the parent), fission (the parent splits into two or more individuals), and fragmentation (a piece of the parent breaks off into several pieces and regenerates).Asexual reproduction has great advantages for organisms that are immobile, or unable to move around. Plants and animals that are rooted to the ground aren’t able to get up and find a partner to mate with, so being able to reproduce on their own is a great option!The other type of reproduction is sexual reproduction, which is when new organisms are created through fertilization. Fertilization involves the fusion of two gametes, like when a human egg and sperm come together. Most animals reproduce through sexual reproduction because it increases genetic variation.
If you contribute half of your genes and your partner contributes half of his or her genes, the genetic makeup of the new individual is far more diverse than if you were to produce a genetically identical offspring through asexual reproduction.
Using Both Types of Reproduction
While most organisms only reproduce through one method, some plants and animals can reproduce both ways. This might sound complicated, but there are some benefits to this adaptation.One of the main upsides of sexual reproduction is that it creates a diverse gene pool. If the environment is unstable, this genetic diversity will allow more offspring to survive and reproduce than if the population had the same genetic makeup.
But if the environment is stable, asexual reproduction might be more beneficial because it is safer to produce a greater number of individuals with the same genetic makeup.For example, if the environment is very stable during one part of the year with plentiful food, water, and other resources, an organism might want to reproduce asexually to create a large, uniform population. But if later in the year conditions change and become harsh, the organism can switch to sexual reproduction to create a population that is more diverse and therefore, better able to withstand the varied conditions.
Let’s take a look at some organisms that reproduce both sexually and asexually.
Most fungi are able to reproduce asexually by producing spores, as well as sexually.
Daffodils are a plant that can reproduce both ways; asexually from their bulb and sexually through seed production. Strawberries are similar in that they can reproduce sexually through seed production, or asexually with runners that spread through the ground and create daughter plants from the parent.
Plants don’t get all the glory though; there are many animals that also reproduce both sexually and asexually. For example, the starlet sea anemone can reproduce asexually through fission and sexually through the production of eggs and sperm. This ability to reproduce both ways is common among other marine invertebrates like sponges and jellyfish.The group of parasites called apicomplexa, which includes the parasites responsible for malaria and toxoplasmosis, also reproduces both sexually and asexually. The sexual phase is called gametogony and the asexual phase is called sporogony. Do these words look slightly familiar? That’s because the phase of gametogony produces gametes and the phase of sporogony produces spores!
What an interesting world we live in! We are surrounded by a great diversity of life, yet it all has one very important thing in common: reproduction.
Because we cannot live forever, we need to create new offspring to carry on our genes. This can be done through asexual reproduction, where an individual identical to the parent is produced, or through sexual reproduction, where a unique individual is produced from the combination of two gametes through fertilization.Both methods have advantages. Sexual reproduction is good for creating a diverse gene pool that can withstand a dynamic and changing environment. Asexual reproduction is beneficial for organisms that aren’t able to move around and for creating a large, uniform population.Some overachievers in nature do both! Having the ability to reproduce asexually when the environment is stable and sexually when it is changing gives these organisms an advantage that they wouldn’t otherwise have; they can modify their strategy when needed.We can find many examples of organisms that use both methods of reproduction: most fungi, plants like daffodils and strawberries, animals like marine invertebrates, and parasites that cause malaria and toxoplasmosis are all organisms that produce both sexually and asexually at different points in their lives.