Difference Between Active and Passive Dispersal

The key difference between active and passive dispersal is that active dispersal is a form of dispersal in which organisms move from one place to another without assistance while passive dispersal is a form of dispersal in which organisms need assistance to move from one place to another.

Dispersal is a mechanism that explains the moving of organisms or propagules such as seeds and spores from one site or place to another site. Generally, organisms move to a breeding or growing site from their birthplaces. Most importantly, dispersal is a key factor in regulating population size and density. Dispersal can be active or passive. In active dispersal, organisms move from one place to another without any assistance. But in passive dispersal, organisms need assistance for the dispersal. Seeds are dispersed passively many times.

CONTENTS

1. Overview and Key Difference
2. What is Active Dispersal
3. What is Passive Dispersal
4. Similarities Between Active and Passive Dispersal
5. Side by Side Comparison – Active vs Passive Dispersal in Tabular Form
6. Summary

What is Active Dispersal?

Active dispersal is the dispersal of organisms without any assistance. Here, organisms move from their birthplace to another place through their own abilities. Generally, adult and juvenile animals show active dispersal. The degree of active dispersal among adult and juvenile animals varies depending on the species. Moreover, different factors affect the active dispersal of organisms.

In general, active dispersal is a density-dependent process. The magnitude of the process mainly depends on local population size, resource competition, and habitat quality and size. Snails and slugs show active dispersal and their dispersal is mainly influenced by population density, habitat complexity, climatic conditions and individual characteristics such as body size or behaviours.

What is Passive Dispersal?

Passive dispersal is a mode of dispersal in which organisms need assistance to move from one place to another place. Seeds of plants mainly disperse by passive dispersal. Marine invertebrates such as sponge and corals use passive dispersal. Those are sessile organisms. Hence, they utilize passive dispersal.

Passive dispersal in seeds occurs in different ways. Seeds use water to disperse. Moreover, they can disperse by the wind. In order to disperse by wind, seeds and fruits have wings, hairs, or inflated processes. Also, sticky seeds stick to clothes of animals and disperse. Furthermore, when animals feed on seeds and fruits, passive dispersal takes place. Similar to seeds, spores use wing and water to disperse. Using passive dispersal, plants colonize new areas and habitats. This extends geographical ranges of species.

What are the Similarities Between Active and Passive Dispersal?

• Plants and animals disperse by active and passive dispersal.
• Some arachnids are able to use both active and passive dispersal.
• Both types of dispersal are responsible for species distribution in new geographical areas and in new habitats.

What is the Difference Between Active and Passive Dispersal?

In active dispersal, organisms move from one location to another location through their own ability without any assistance. But, in passive dispersal, organisms, seeds and spores move from one place to another using the assistance of animal, wind or water. So, this is the key difference between active and passive dispersal. For example, adult and juvenile animals show passive dispersal while some invertebrates such as sponge and corals, plant seeds and spores show passive dispersal.

Below infographic summarizes the difference between active and passive dispersal.

Summary – Active vs Passive Dispersal

Dispersal is the movement of organisms or seeds from their borne place to another place in order to settle and breed.  Active dispersal and passive dispersal are two types of dispersal. In active dispersal, organisms move through their own ability without assistance. In contrast, organisms need assistance in passive dispersal. Thus, this is the key difference between active and passive dispersal.

Reference:

1. “Causes And Consequences Of Dispersal In Plants And Animals | Learn Science At Scitable”. Nature.Com, 2020, Available here.

Image Courtesy:

1. “Dandelionseed” By Hmbascom – Own work (CC BY 3.0) via Commons Wikimedia