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Ch. 27 - Diversification of Eukaryotes
Freeman - Biological Science 7th Edition
Freeman7th EditionBiological ScienceISBN: 9783584863285Not the one you use?Change textbook
Chapter 27, Problem 4

How can dinoflagellates be harmful to humans?a. They are transmitted by mosquitoes and cause malaria.b. They produce toxins that can be absorbed by clams and other shellfish which, when eaten by people, can lead to paralytic shellfish poisoning.c. They cause amoebic dysentery which leads to severe diarrhea and dehydration.d. They are transmitted by tsetse flies and cause 'sleeping sickness.'

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1
Identify the organism in question, which is dinoflagellates, a type of plankton known for their role in aquatic ecosystems.
Understand that dinoflagellates can produce toxins, which is a key characteristic relevant to the question.
Recognize that these toxins can accumulate in marine organisms such as shellfish, which are then consumed by humans.
Connect the consumption of toxin-contaminated shellfish to human health issues, specifically paralytic shellfish poisoning.
Conclude that the correct answer involves the relationship between dinoflagellates, the toxins they produce, and the impact on humans through the consumption of contaminated shellfish.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Dinoflagellates

Dinoflagellates are a group of single-celled organisms found in marine and freshwater environments. They are known for their unique characteristics, including the presence of two flagella that allow them to move. Some species are photosynthetic, while others are heterotrophic. Importantly, certain dinoflagellates can produce harmful toxins that affect marine life and humans.
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Toxins and Shellfish Poisoning

Certain dinoflagellates produce potent toxins, such as saxitoxin, which can accumulate in shellfish like clams and mussels. When humans consume these contaminated shellfish, they can experience paralytic shellfish poisoning (PSP), characterized by symptoms such as numbness, dizziness, and respiratory failure. This phenomenon highlights the importance of monitoring shellfish for harmful algal blooms caused by toxic dinoflagellates.
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Harmful Algal Blooms (HABs)

Harmful algal blooms (HABs) occur when certain algae, including toxic dinoflagellates, proliferate excessively in water bodies, often due to nutrient pollution. These blooms can produce toxins that are harmful to marine life and humans, leading to health risks and economic impacts on fisheries and tourism. Understanding HABs is crucial for managing water quality and protecting public health.
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