Lesson 24: Synapsids and Origin of Birds

Question 1

whales

Answer 1

use of axial swimming instead of paraswimming
- propelling by flexing axial musculature
- whales do it by using a vertical motion

nasal opening on top of their head
- allow them to be more aquatic

zigapophyses are lost
- torsion and bending

hindlimbs having been lost
- ^^arose out of a terrestrial lifestyle

Question 2

live, adult bottle nose dolphin with hindlimbs caught by hunters

Answer 2

• over evolutionary history those genes have been turned off
• there was a mutant and the gene was turned on

Question 3

sociality

Answer 3

-being social is defined as group living
- the bigger the group, the more social
- being social does not mean you’re nice, it just means you are in a group

Question 4

distribution

Answer 4

refers to the area used by species

Question 5

homerange

Answer 5

refers to an individual

Question 6

territory

Answer 6

a subset of the homerange that is successfully defended
- some species are not territorial but they all have a homerange

Question 7

homerange vs. body mass

Answer 7

• large animals have a large homerange
• ^^^ the space needed to an individual animal to get the resources they needed
  – size of homerange increases disproprotionately
  —- think about really large animas - you need a larger homerange
• you start to run into problems like fragmentation of the habitat
  ^^^ex: a pond if you are not aquatic – you have to go around it and you cannot use it
  ^^why it increase at such a rapid rate - resource distribution and needs also accounts for the rate

Question 8

distribution of resources also affects the homerange size

Answer 8

• this in turn affects sociality
  – if an animal is grazing with another one – animals tend to congregate with another and in turn be more social

if the resources are widely distribute, it does not pay off to share and eat with the friend, thus does not encourage group living/sociality

Question 9

spotted hyena (40Kg)

Answer 9

• at the individual level it is capable of taking a 30 or 20 kg animal – working on its own, it is not going to be able to catch 200 kg wildebeest
  — but when working in a group it can – highly social environment

Question 10

vilagence

Answer 10

when you live in a group, the group itself can be more vilagent

Question 11

diluton

Answer 11

when you’re in a group and a predator is coming, less likely for you to be singled out and attack

Question 12

confustion

Answer 12

• large group of fleeeting prey
• very difficult to single out prey from a group
• extremely difficult to track the single zebra in a herd of zebra

Question 13

group defense

Answer 13

• how useful it can be to defend against a predator as a herd

Question 14

diet and size of african bovidae: small forest dwelling antelopes

Answer 14

• highly selected in the choice of plants that they consume
• type 1 diet
• individual living, or sometimes living with mates
• hide from predators

Question 15

diet and size of african bovidae: medium sized

Answer 15

• type 2 diet
• less selective
• intermediate sociality

Question 16

diet and size of african bovidae: large

Answer 16

• type 3
• less selectve
• often migratory
• use group defense

Question 17

small animals

Answer 17

very asexual

Question 18

larges species stomach

Answer 18

• large species have a large stomach while small animals have a large stomach
• metabolism of large species does not increase with species size as fast as stomach ratio
• large animals especially an endotherm is not as expensive per gram to maintain - overall, yes – but per gram, now (much less SA ratio)

Question 19

as an animal gets larger, its stomach gets larger

Answer 19

• easier for stomachs of larger animals to be more efficient on a per gram basis
• have the ability to be less selective
• decreased metabolism??

Question 20

type 1 diet

Answer 20

• has to be highly selective
• if a type 1 animal comes across a plant with leaves and buds and the leaves are less energy filled…
  —- will eat all the buts
  —– changes the distribution of the resource

Question 21

less selective diet

Answer 21

does not change the distribution of the diet

Question 22

horns/antlers use

Answer 22

social/self defense/communication

Question 23

horns

Answer 23

have a bony core and are covered by a keratin sheath

Question 24

antlers

Answer 24

• usually confined to males
• branched
• made of only bone
• covered by highly vascularized skin

Question 25

evolution and sexual dimporhism of animals: antlers/horns

Answer 25

in the miocene the eurasian woodlands became more open (form a closed environment)
- there were ruminants living there who experienced this –> they go bigger and became more territorial –> have more polygeny
^^ this fules intense male-male fighting
- sexual selection from evolution of territoriality
- exactly why the ruminants that evolved in north America instead of Eurasia did not evolve horns ( camalids - llamas, alpacas, cammels, horses)

^^^^ in north america during the changing climatem there was not percistent open woodland stage –> transitioned from forests to grasslands
- the OPEN grasslands FULES the intense territorality
– go from dense woodlands to open/sparse woodlands
– don’t get territorality between the extreme