TED-Ed: How do germs spread (and why do they make us sick)? - Yannay Khaikin and Nicole Mideo

The video discusses how germs, including bacteria, fungi, protozoa, and viruses, are omnipresent and can affect our health. It explores why some germs are harmless while others are deadly, attributing this to evolutionary processes. The trade-off hypothesis suggests germs evolve to balance virulence and transmission. Rhinovirus, causing common colds, is used as an example, showing how it evolves to be less virulent to ensure host mobility and transmission. Other germs, like the malaria parasite, use different transmission modes, leading to more severe symptoms. The video concludes with strategies to direct germ evolution towards milder forms through disease-control methods.

What are germs capable of doing when they interact with our bodies?

• They can only cause mild symptoms.

• They always lead to severe diseases.

• They have no effect on human health.

• They can change how we feel and function.

Why do some germs cause more harm than others?

• Due to their mode of transmission.

• Because they are more colorful.

• Due to their ability to glow in the dark.

• Because they are larger in size.

What is the main idea behind the trade-off hypothesis?

• Germs evolve to be as harmful as possible.

• Germs balance between replication and transmission.

• Germs do not evolve over time.

• Germs prefer to stay in one host forever.

How does the rhinovirus ensure its successful transmission?

• By balancing replication to keep the host mobile.

• By avoiding replication altogether.

• By replicating too little.

• By making the host extremely sick.

What is a key difference between the transmission of rhinovirus and malaria?

• Both rely on water for transmission.

• Rhinovirus is transmitted by mosquitoes.

• Malaria requires host mobility for transmission.

• Rhinovirus relies on close contact, while malaria is transmitted by mosquitoes.

What can be done to reduce the harmfulness of infectious diseases according to Dr. Paul Ewald?

• Direct their evolution through disease-control methods.

• Ignore the presence of germs.

• Encourage germs to evolve stronger forms.

• Use traditional methods to eradicate germs.

Why might germs transmitted by insects cause more severe symptoms?

• They are transmitted through air.

• They depend less on host mobility.

• They require the host to be very active.

• They are less harmful.