Organism growth and the environment | Middle school biology | Khan Academy

Hey, have you ever seen this kind of plant before? It's called a dandelion. If you live in a tropical climate, it might be unfamiliar, but if you live in a more temperate zone, you'll probably recognize it, as it's a very common plant. Dandelions make yellow flowers that develop into balls of these fluffy white seed heads that fly off the plant. This can happen by a gust of wind, by animals spreading them, or even by someone blowing on the plant.

When this happens, its seeds fly into the air and land on new spots on the ground. From there, the seeds can grow into new dandelions, starting the whole cycle over. But why do dandelions do this? Why do they turn into puff balls? Why are they yellow? If they don't have brains, how do they seem to know when to release their seeds?

These are all complicated questions, but to begin answering them, we can talk about what influences the growth and development of dandelions and, in turn, all living things. So what determines how our dandelion will grow? Its genes and its environment. Let's take a moment to review what genes are. Genes make up the hereditary material inside an organism's cells. Genes provide the information about what traits an organism has.

So, the reason that our dandelion has yellow petals and develops fluffy white seed heads lies within its genes. Any influence genes have on the way an organism grows is called a genetic factor. So, if one dandelion has more seeds than another as a result of which version of a certain gene it has, we can say that the difference in seed number is due to a genetic factor.

The other major influence on how our dandelion grows is its environment. But what makes up an organism's environment? The environment is the set of conditions an organism is exposed to during its life. For our dandelion, this includes temperature, how much light and water it gets, and which nutrients are present in the soil where it grows. Any influence the environment has on an organism's growth is called an environmental factor.

So, if one dandelion plant is exposed to more sunlight than another and grows bigger as a result, we can say that the difference is due to an environmental factor. But plants aren't the only living organisms that are motivated by these factors; animals are also influenced by their genes and environment. For example, let's look at dogs.

Dogs come in many different shapes, sizes, colors, and each has their own unique features. We can see this when looking at different breeds, like pugs, which are small with squishy faces, and golden retrievers, which are large with flowing locks of golden fur. These traits are largely determined by which genes each breed of dog has, or in other words, by genetic factors.

But dogs are also influenced by environmental factors too. For instance, how much food they get as they grow helps determine their size, and what they learn from other dogs and from people helps determine their behaviors, like when you teach your dog a new trick.

And now you know how organisms are influenced by genetics and their environment when it comes to growth and development. Let's do a quick review of what you've learned today. First, there are two main factors that influence an organism's growth: these are genetic and environmental factors. Genetic factors are the genes the organism gets from its parent or parents, while environmental factors are the conditions an organism is exposed to as it grows.

These factors show that all living organisms have a couple of things in common, even dogs and dandelions. So while our interactions with them may differ, like how you can't teach a dandelion to sit like you can with a dog, both organisms experience growth and development through their own unique genes and environments.