This lesson differentiates among three types of dispersion patterns, focusing specifically on clumped dispersion. You’ll learn what causes clumped dispersion and explore some examples.
Types of Dispersion Patterns
If you’re hiking through a forest, you might notice that some species of plants – like certain flowers or bushes – seem evenly spaced, while others – like wild mushrooms – are clustered together in only certain parts of the habitat.
Within any given plant or animal population, or group of individuals of the same species living in the same area, individuals can be spaced in different ways called dispersion patterns. There are three types of dispersion patterns.Clumped dispersion is when individuals in a population are clustered together, creating some patches with many individuals and some patches with no individuals. In uniform dispersion, individuals are spaced evenly throughout an area. And in random dispersion, individuals are arranged without any apparent pattern.In natural populations, random dispersion is rare, while clumped dispersion, which we’ll focus on in this lesson, is the most common pattern.
Clumped dispersion is often due to an uneven distribution of nutrients or other resources in the environment. It can also be caused by social interactions between individuals. Additionally, in organisms that don’t move, such as plants, offspring might be very close to their parents and show clumped dispersion patterns. Let’s further examine each of these three reasons for clumped dispersion.
Uneven Nutrients and Resources
Within a single habitat, some areas are more ideal to live in than others because they have more food, water, sunlight, or other resources. This can cause many individuals of a population to accumulate in this ideal location. For example, you might find a patch of mushrooms growing on an old rotting log but nowhere else in a forest.
This is because dark, moist, decaying places provide everything a mushroom needs to grow.Another example of clumped dispersion due to uneven resources is when you see many turtles hanging out on a log in or near a pond. All turtles in the pond need to get out of the water and warm up under the sun, and the uneven distribution of logs in the pond causes them to cluster together.
Many animals purposely form groups to enhance their survival. For example, mammals such as deer and buffalo form protective herds because it’s much easier for predators to attack a lone animal than a large group.
Similarly, many fish form schools, and birds form flocks. Carnivores like wolves and lions form packs to increase their hunting efficiency. Packs, herds, flocks, and schools all represent clumped dispersion patterns.
Because plants can’t get up and move around, they often show clumped dispersion simply due to lack of dispersal. Be careful not to confuse dispersal with dispersion. Dispersal is the movement of individuals away from where they were born, while, as we noted earlier, dispersion is the spatial arrangement of individuals in a population.Plants rely on wind, water, or animals to carry, or disperse, their seeds to new locations. If this doesn’t happen, plant seeds will germinate right next to their parents. For example, sometimes if you look under a large tree, you’ll see a bunch of little trees growing, creating a clumped pattern of individuals.
Individuals of a population can be spaced in different ways called dispersion patterns.
In uniform dispersion, individuals are evenly spaced. In random dispersion, individuals are randomly arranged. The most common spatial arrangement is clumped dispersion in which individuals are clustered together.An area with an uneven distribution of food, water, moisture, temperature, or other resources can cause clumped dispersion.
This pattern can also be caused by the formation of social groups based on protection or hunting. In plants, clumped dispersion is common when offspring fail to disperse from parent plants.
Population: group of individuals of the same species living in the same areaDispersion Patterns: different ways individuals can be spacedClumped Dispersion: when individuals in a population are clustered togetherUniform Dispersion: individuals are spaced evenly throughout an areaRandom Dispersion: individuals are arranged without any apparent pattern
Build your knowledge in preparation to:
- Define dispersion patterns and related terminology
- Describe ways in which different variables can affect dispersion patterns