keystone species

Question 1

keystone species

Answer 1

species that have low biomass, but large impact on community and it’s biodiversity (can be a predator)

Question 2

keystone species and competitive excluesion

Answer 2

keystone species may keep a predator below the carrying capacity to reduce the risk of competitive exclusion

Question 3

Bob Paine

Answer 3

took piaster starfish (top predator) out of tidepools

• decreased tidepool biodiversity
• allowed bivalves and barnacles to dominate
• 15 species to 8 (or 5)

Question 4

Malaysian Strangler fig

Answer 4

keystone species

• provides resting location for a ton of species even though it’s parasitic to the tree
• provides year round resources that support monkeys and 50 kinds of birds

Question 5

communities with higher biodiversity:

Answer 5

• more productive and produce more biomass
• more stable in their productivity
• handle environmental stress better
• more resistant to invassive species

Question 6

Dominant species

Answer 6

• most abundant with highest biomass (not necessarily keystone)
• some ppl think they’re the best competitors; others think they’re the best at avoiding prey
• often times invassive species become dominant

Question 7

Chestnut blight introduction

Answer 7

killed a lot of the American chestnuts

-had small impact on some species, but big impact on others

Question 8

sea otters

Answer 8

• eat sea urchins
• w/o otters, urchins eat kelp forests
• no more habitat for a bunch of marine life
• even affected bald eagle

Question 9

ecosystem engineers

Answer 9

• cause physical changes in environment that affect community structure
• e.g. beavers

Question 10

herbivore affect on plant diversity

Answer 10

• can increase, decrease, or have no effect

- have to look at food preference and plant competition across ecosystem

Question 11

Intertidal snails

Answer 11

• eat red (Chondrus crispus) and green ((Enteromorpha spp.) algae
• when snails are excluded, the green algae competitively displace the red one

Question 12

wolves in yellowstone

Answer 12

• ate elk and changed elk behavior
• elk avoided valleys
• vegetation returned, banks stabilized, rivers were fixed
• more birds, beavers, ducks, and muskrates
• wolves ate cayotes = more rabits and hawks