17.Body Size

Question 1

Name some traits of a species that are affected by its body size.

Answer 1

Resource requirements, dispersal capacity, reproductive rate, evolutionary rate, interactions with other species

Question 2

What is the different between interspecific and intraspecific?

Answer 2

Inter = between species
Intra = within species

Question 3

What is Bergmann’s Rule?

Answer 3

Within related organisms, larger bodied species tend to be found in colder climates, and smaller bodied species in warmer climates

Question 4

Is Bergmann’s rule inter- or intra- specific? What rule covers the other comparison?

Answer 4

Bergmann’s rule is interspecific, James’s rule often used for intraspecific examples

Question 5

What types of species does Bergmann’s rule apply most accurately to?

Answer 5

Mammals and birds

Question 6

What’s the difference between an endotherm and an ectotherm?

Answer 6

Endotherms - produce and store their own body heat
Ectotherms - rely on external heat

Question 7

Does Bergmann’s rule apply best to endotherms or ectotherms?

Answer 7

Endotherms

Question 8

Except for island environments, what is the best correlated factor with bird body size?

Answer 8

Temperature

Question 9

What was Bergmann’s original reasoning for his rule?

Answer 9

Surface area to volume ratio
- Larger species have an advantage retaining heat in cold environments

Question 10

How can dispersal abilities explain Bergmann’s rule?

Answer 10

Larger organisms have greater dispersal capabilities which could be an adaptive feature for low productivity, seasonal environments.

Question 11

What suggested explanation for Bergmann’s rule involves competition?

Answer 11

Interspecific competition favours small body size and intraspecific competition favours large body size. Therefore small body size may be an advantage in high-diversity locations (tropics) and larger body size in less diverse regions.

Question 12

Where are the widest ranges of plant heights found?

Answer 12

Cold, dry, low productivity environments

Question 13

Where are shorter species of plants noticeably absent?

Answer 13

Wetter, warmer, more tropical environments

Question 14

What would you expect Bergmann’s rule to show about body size in relation to elevation? Is this seen?

Answer 14

An increase in body size with elevation
- Results are ambiguous and inconclusive

Question 15

What is deep sea gigantism? Is this due to temperature?

Answer 15

The tendency for species of deep-sea dwelling animals to display a larger size than their shallower-water relatives.
- Probably not

Question 16

What is Foster’s rule also known as ?

Answer 16

The island rule.

Question 17

What does Foster’s rule say?

Answer 17

In comparison with relatives on main-lands, small species tend to increase in size on islands and large species tend to decrease in size.

Question 18

What is a likely explanation for larger animals following the island rule?

Answer 18

May adapt and become smaller because they are adapting to a resource poor environment.

Question 19

What is a possible reason for smaller animals getting larger on islands?

Answer 19

Release from predation

Question 20

What are island elephants a very good example of?

Answer 20

Foster’s rule
- Degree of dwarfism on the Asian islands is predictable from other islands, strong pattern of size

Question 21

What is insular woodiness?

Answer 21

the evolutionary transition from herbaceousness toward woodiness on islands

Question 22

What are some possible explanations for second insular woodiness?

Answer 22

Competition for sunlight may favour taller, stronger plants
Woodiness preserves water during droughts
Could be an indirect result of longer lifespan (lack of large native herbivores)

Question 23

In the islands of what regions is IWS seen most?

Answer 23

Tropics and subtropics

Question 24

Which set of islands represents about 19% of all transitions to IWS?

Answer 24

Canary Islands

Question 25

How does distance to the nearest continent correlate with IWS rates?

Answer 25

Oceanic islands tend to have higher rates of IWS (further from continents)

Question 26

How do IWS rates correlate with the amount of herbivore mammals?

Answer 26

Less herbivore mammals tends to mean more IWS

Question 27

Is IWS more or less common on volcanic islands?

Answer 27

More

Question 28

Describe a process by which volcanic eruption may increase IWS.

Answer 28

Shorter, more herbaceous plants are killed off by thick ash layers
- While taller, woodier plants are able to withstand or resprout