Lab 9: Mutualism & Nitrogen Fixation

Question 1

community

Answer 1

-group of 2 or more populations of different species occupying the same geographical area

Question 2

intraspecific interaction

Answer 2

-interaction within species

Question 3

interspecific interaction

Answer 3

-interaction btwn or among species

Question 4

ectosymbiosis

Answer 4

-one individual lives on another organism

Question 5

endosymbiosis

Answer 5

-one organisms lives inside of another organism

Question 6

obligate symbiosis

Answer 6

-atleast one of the species must be in relation with the other species to survive

Question 7

facultative symbiosis

Answer 7

-beneficial, but not necessary for survival

Question 8

mutualism

Answer 8

-interaction btwn two organisms where both organisms benefit from the relationship in terms of increased fitness

Question 9

diazotrophs

Answer 9

-organisms that can fix atmospheric nitrogen into a biologically usable form

Question 10

how does nitrogen occur in the atmosphere?

Answer 10

-as a diatomic molecule (triple bonded)

Question 11

why does nitrogen need to be fixed?

Answer 11

• aka broken into molecules which contain only a single nitrogen
• only way living organisms can use it

Question 12

trophic mutualism

Answer 12

-both symbionts gain nutrients

Question 13

defensive mutualism

Answer 13

-atleast one member of the mutualism is defended from predators or parasites in exchange for food (usually)

Question 14

dispersal mutualism

Answer 14

-plants & pollinators that disperse their pollen
OR
-plants & fruit eaters that disperse the plant’s seeds

Question 15

rhizoia

Answer 15

• anaerobic diazotroph bacteria that live in the roots of legumes (bean plants)
• legumes don’t need this if there’s another source of nitrogen (facultative)
• cannot fix nitrogen without a host plant

Question 16

pink nodules

Answer 16

-contain rhizobia that’re actively fixing nitrogen

Question 17

green nodules

Answer 17

-contain rhizobia that are reproducing

Question 18

scatterplots

Answer 18

• x/y axis all numerical

- one point doesn’t directly predict the other (non-continuous data)

Question 19

line graphs

Answer 19

• x and y are numeric

- points do predict each other (continuous data, rates, etc)

Question 20

bar graphs

Answer 20

• aka histograms (when they’re of frequencies)
• x is categorical (not numerical)
• all items have one y value (aka count)

Question 21

adaptations in terrestrial snails

Answer 21

• hygroscopic slime
• aestivation
• jumping
• hermaphroditism
• development in eggs
• stalked-eyes

Question 22

hygroscopic slime

Answer 22

-attracts water rather than repelling

Question 23

aestivation

Answer 23

-a behavioral adaptation where snails seek a hiding place to avoid hot and dry weather

Question 24

snail jumping

Answer 24

-another behavioral adaptation that prevents water loss from their foot

Question 25

stalk-eyed snails

Answer 25

-increases the snail's field of vision

Question 26

g x e interaction

Answer 26

- environmental stress has different effects depending on genotype - a certain genotype (actual nucleotide sequence in DNA) doesn't always result in the same phenotype