Parasites And Symbiosis- Relation and Diseases

parasites and symbiosis

As humans, we are the independent individuals. We, the humans breathe with the use of our own organs, find shelter on our own and prepare and obtain food in our own respective ways. But this scenario is not true for every organism. There are few species which are completely depended on another organism throughout their lifespan.

Let’s have a glimpse of parasites and their life cycle.


The word parasite is derived from the Greek word meaning -one that eats at another table and is estimated to be from around 5900BC.

Parasites are an incredibly varied group of organisms that live within host cells. They are smaller than their host organism and reproduces faster by causing more damage to the host.They receive all sort of benefits like food and shelter from the host. Their size ranges from tiny, single-celled organisms to worms over 20- 30 m in length.

For example- Tapeworms.

They are flat, segmented worms, live in the intestines of animals by absorbing the host’s nutrients.

Symbiosis Vs Parasitism

Symbiosis refers to a long period interaction between two different species.  In some cases, both species benefit from the interaction and this becomes mutualism. The larger organism is considered a host because, in a symbiotic relationship, it is the larger organism upon or inside of which the smaller organism lives. The smaller organism is considered to be a symbiont, that lives in or on the host.

Parasitism is the type of symbiotic relationship or long-term relationship between any two species either plants or animals. Here the parasite gains benefits by the host which in turn causing harm without killing the host organism.

Leeches, fleas, ticks, and lice are few examples of parasites that don’t normally cause disease directly. They suck blood from the host without causing any harm and discomfort to their host.

Types of Parasitism

Parasites can be classified based on their size, characteristics, and relationship with the host.

Endoparasites and ectoparasites are two types of parasites.

  • Endoparasites: A parasites living inside the host’s body.

For example-Plasmodium falciparum, a parasite which causes malaria in humans.

  • Ectoparasites: A parasites living outside the host’s body.

For example- Bedbug, a parasite which causes skin irritation.

These parasites may also transmit disease-causing pathogens to other species of animals.The life of a typical parasite commonly includes certain developmental stages. During this time, the parasite goes through two or more changes in body structure as it lives and moves through one or more hosts. The number of parasites exceeds the number of free-living organisms, means the parasitic lifestyle has been a successful one over the years.

Stay tuned with Byju’s to learn more about Parasites and Symbiosis.

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