Reading: I Contain Multitudes

Question 1

Hemiptera

Answer 1

• true bugs (bed bugs, assassin bugs, scale bugs)
• characterized by stabbing sucking mouthparts
• DRINK PLANT SAP (bacterial symbionts allow them to specialize in this)
• plant pests

Question 2

plant sap is rich in… but poor in…

Answer 2

• sugar

- important nutrients (10 essential amino acids)

Question 3

What do Buchnera bacteria do for aphids?

Answer 3

supplement their meal of sap by providing amino acids

- only together can they subsist on phloem sap

Question 4

chemosynthesis

Answer 4

making your own food using chemical energy rather than light or solar energy

Question 5

Why do the worms in the “Rose Garden” not have guts?

Answer 5

They rely completely on bacteria for all nutrients. They contain an organ called a trophosome which contained pure sulphur crystals. Bacteria oxidize sulphides that come out of deep sea vents and used liberated energy to fix carbon churning out pure sulphur.

Question 6

What did all the deep-sea vent creatures evolve from?

Answer 6

Shallow water species that became hosts for deep-sea microbes.

Question 7

Olavius algarvensis

Answer 7

• close relative of the earth worm
• lives on Tuscan island Elba
• completely white because the symbiotic bacteria beneath their skin is full of sulphur globules
• has five symbionts: two that process sulphates, two that process sulphides, and a fifth unknown one

Question 8

How were gut microbes clustered?

Answer 8

clustered based on multiple factors including ancestry

but more importantly diet

Question 9

Which group had the highest diversity of gut bacteria and why?

Answer 9

Herbivores, then omnivores, then carnivores having least diversity. Plant tissue is the most difficult to digest because it contains the most complex carbohydrates which vertebrates don’t have the capacity to digest.

Question 10

mammalian success was founded on…

Answer 10

vegetarianism

Question 11

Why does the position of the fermentation chamber matter?

Answer 11

microbiomes of foregut fermenters are more similar than hindgut fermenters (similarities transcend ancestry).
hindgut - digest food with own enzymes first then pass along to symbionts
foregut - give to symbionts first and thus lose some nutrients but they just eat the symbionts after

Question 12

Gut microbes had an…

Answer 12

adaptive radiation after colonizing our guts

Question 13

Macrotermites

Answer 13

• farm a fungus in their nests, feeding it bits of wooden shrapnel, fungus splits cellulose into different components creating a compost that the termites can then eat
• bacteria in their guts breaks down compost even more

Question 14

Queen termite

Answer 14

lacks gut microbes, her symbionts are the termites in the colony that feed her