ecological niche

Question 1

niche

Answer 1

organisms place in biotic environment (relation to food and enemies) and abiotic environment (physical surroundings)

Question 2

Hutchinson’s niche

Answer 2

n-dimensional hyper volume (n=number of environmental factors)

Question 3

single niche axis

Answer 3

zone of intolerance, zone of stress, optimal zone

Question 4

fundamental niche

Answer 4

the range a species could occupy without competitive pressures

Question 5

realized niche

Answer 5

the range a species actually occupies

Question 6

how does environmental complexity relate to niches

Answer 6

the more complex an environment, the less oportunity for competition
-more species diversity

Question 7

Karr and Roth experiment

Answer 7

• measured height of trees (to assess complexity)
• measured number of warbler types in trees
• more complexity = more biodiversity

Question 8

why can phytoplankton/algae/diatoms coexist

Answer 8

• partially due to complexity of environment

- mostly due to varying trophic positions and different nutritional need ratios

Question 9

what happens if 2 species have same needs exactly

Answer 9

• cannot coexist

- one will outcompete the other

Question 10

Park’s flour beetles

Answer 10

• both types have large niches when no competition
• smaller niches when coexisting
• T. castaneum wins in hot, wet environments
• T. confusum wins in cold, dry environments
• first colonizer wins in intermediate environments

Question 11

Priority effect

Answer 11

when the first colonizer wins at competition

Question 12

Gause’s competitive exclusion

Answer 12

• When grown allopatrically, they followed logistical curve
• when raised sympatrically, p. aurelia competitively excluded p. caudatum
• p. aurelia’s k was lowered though

Question 13

Barnacles in intertidal zones

Answer 13

-Semibalanus balanoides is restricted to lower- mid tidal positions because it is sensitive to drying out
Chthamalus stellatus is restricted to upper tidal positions because of competition with the other guy

Question 14

Heske’s granivorous rodent experiment

Answer 14

• if you remove big grainivorous rodents, there will be an increase in the number of small ones
• insectivore rodents shouldn’t be impacted

Question 15

niche partitioning

Answer 15

basically figuring out how two species can coexist by sharing resources and limiting their fundamental ranges
-usually involves different use of resources

Question 16

DW analysis

Answer 16

• figuring out the mean usage of a resource and finding the upper and lower limit by adding and subtracting the standard deviation
• no coexistance if ranges overlap

Question 17

warbler example of niche partitioning

Answer 17

Robert McArthur found that different warblers used different sections of the same tree

Question 18

temporal partitioning example

Answer 18

common spiny mouse and golden spiny mouse are both nocturnal, but when grown sympatrically, the golden one becomes diurnal

Question 19

Diamond fruit doves

Answer 19

big ones eat big fruit; small ones eat small fruit

Question 20

Niche partitioning between sexes

Answer 20

this happens

Question 21

Character displacement requirements

Answer 21

• the differences in sympatry must be greater than in allopatry
• the differences cannot be due to founder effect
• difference must be genetic
• must have effect on resource use
• must be competition for resource
• not due to different available resources

Question 22

Hutchinson’s ratio

Answer 22

• when organisms live in sympatry, tend to have size ratios of 1:1.1 to 1:1.4
• e.g. felis canine sizes bt sexes

Question 23

Historical replacement

Answer 23

• when one species replaces another
• slides mention azure and blue tits, but this is honestly just dispersal with some overlap
• starlings and house sparrows evict native bluebirds and flickers from cavity nest sites

Question 24

contiguous allopatry

Answer 24

• 2 species are allopatric, but the regions in which they live are adjacent to each other
• e.g. chipmunks along sierra nevada mountains
• e.g. warblers on mt. karimuni

Question 25

chipmunks in contiguous allopatry

Answer 25

alpine, lodgepole pine, yellow pine, least

-lodgepole is most dominant, but yellow pine is dominant to the least