Insect Size and Oxygen Levels

The video explores why insects were much larger 300 million years ago compared to today. It discusses theories such as the exoskeleton's weight and oxygen delivery systems as factors limiting insect size. Dr. Jon Harrison explains that the exoskeleton theory lacks substantial evidence, while the oxygen delivery theory is supported by historical oxygen levels. During the late Paleozoic era, higher atmospheric oxygen may have allowed for larger insects. The video concludes with an invitation for viewers to ask questions and share comments.

What is the largest insect currently on record?

• Meganeura Dragonfly

• Goliath Beetle

• Giant Weta

• Atlas Moth

Which theory suggests that the exoskeleton limits the size of insects?

• Oxygen delivery theory

• Nutritional availability theory

• Exoskeleton weight theory

• Predation theory

According to Dr. Harrison, what is the relationship between exoskeleton size and body size in insects?

• Exoskeleton size does not affect body size

• The proportion is the same in both large and small insects

• Smaller insects have proportionally larger exoskeletons

• Larger insects have proportionally larger exoskeletons

How do insects primarily breathe?

• Through lungs

• Through skin

• Through gills

• Through tracheal tubes

What are tracheoles in insects?

• Sensory organs

• Muscles for movement

• Tiny tubes for oxygen diffusion

• Large air sacs

What atmospheric condition in the past is believed to have allowed for larger insects?

• Higher nitrogen levels

• Higher oxygen levels

• Lower carbon dioxide levels

• Higher humidity levels

What was the approximate oxygen level during the late Paleozoic era?

• 21%

• 25%

• 40%

• 32%

What is the current oxygen level in Earth's atmosphere?

• 21%

• 18%

• 25%

• 32%

What does Dr. Harrison conclude about the theories on insect size?

• There is a definitive answer

• Oxygen theory is disproven

• Exoskeleton theory is proven

• Theories are still being explored

What does the narrator express about the current size of insects?

• They should be extinct

• They should be smaller

• They should be larger

• They are fine as they are