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Ch. 27 - Diversification of Eukaryotes
Freeman - Biological Science 8th Edition
Freeman8th EditionBiological ScienceISBN: 9780138276263Not 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: Dinoflagellates are a type of marine plankton, not a virus or bacteria, and are not transmitted by insects.
Understand the nature of harm: Dinoflagellates can produce toxins that are harmful to other marine life and humans.
Relate to human impact: These toxins can accumulate in shellfish that filter large amounts of water containing toxic dinoflagellates.
Recognize symptoms in humans: When humans consume these contaminated shellfish, they can suffer from paralytic shellfish poisoning, which affects the nervous system.
Choose the correct answer: Based on the information, the correct answer is b. They produce toxins that can be absorbed by clams and other shellfish which, when eaten by people, can lead to paralytic shellfish poisoning.

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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 in severe cases, respiratory failure. This phenomenon highlights the ecological impact of dinoflagellates on food webs and human health.
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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 lead to significant ecological and health issues, including fish kills and the contamination of seafood. Understanding HABs is crucial for managing water quality and protecting public health from the risks associated with consuming affected marine organisms.
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