lecture 8

Question 1

what anatomical (2) and behavioral (1)characteristics of crocodilians demonstrate their relatively close relationship to birds?

Answer 1

1. 4 chambered heart
2. oneway air flow through the lungs
3. maternal care of offspring

Question 2

what specific adaptations allow birds to fly? 5 main things ( things under them)

Answer 2

1. lightweight skeleton
   - hollow limb bones
   - fewer individual bones
2. skeleton structure
   - flight bones large flight muscles attach to a keeled sternum
3. Feathers
   - sturdy and light
   - flight: on wings, provide lift
   - streamline the surface of the body
   - insulate
4. reduced weight
   - absence of teeth
   - absence of urinary bladder
   - 1 single ovary- matured egg laid as soon as it has a shell
5. metabolic adaptations (flying=energetically expensive)
   -high metabolic rate provides energy for flight muscles (high Tb-39 to42 degrees celcius)
   - efficient consumption &distribution of O2 :
   #4 chambered heart
   #one way flow through system- oxygenated and deoxygenated blood dont mix

Question 3

How do the structures in bird’s bill , wings, and feet reflect its dietary and habitat specializations? (using examples)

Answer 3

Examples: bills

1. hummingbirds that drink nectar=long, thin bills
2. parrots eat hard nuts=stout, sharp bills

wings and feet are adapted to birds’ flying habits and habitats :

e. g. ducks have webbed feet that allow them to in water.
e. g. albatrosses have long, thin wings for flying long distances

Question 4

during the Mesozoic era, why were the most mammals active only at night?

Answer 4

to avoid competition with and predation by dinosaurs, most which were active during the day

Question 5

on what basis are the 3 major groups of living mammals distinguished?

Answer 5

On the basis of their reproductive habits.

1. Monotremes lay eggs
2. marsupials give birth to relatively undeveloped young after a short period of gestation
3. placentals give birth to move developed young after a long period of gestatio

Question 6

what 3 key adaptations in mammals allowed them to be active under many environmental conditions

Answer 6

insulating fur and fat and a high metabolic rate that generates lots of body heat

Question 7

3 characteristics of living archosaurs: crocodilians and birds

Answer 7

1. 4-chambered heart
2. one-way airflow through the lungs
3. strong maternal behaviour

Question 8

crocodilians include 2 species

Answer 8

crocodiles and alligators

Question 9

archosaurs include 2 living groups

Answer 9

aves and crocodilia

Question 10

the aves descended from…(recent descendant)

Answer 10

dinosaurs

Question 11

3 things the aves have in common with the dinosaurs they decended from

Answer 11

1. skeletal structure
2. scales on legs and feet
3. walking posture

Question 12

3 things the aves have that is different from the dinosaurs they decended from

Answer 12

1. keratinized bill & no teeth

2. feathers and wings

Question 13

earliest bird known

Answer 13

archaeopteryx

Question 14

archaeopteryx still dinosaur like 4 characters

Answer 14

1. claws on forelimbs
2. teeth
3. many bones in wings and vertebral column
4. poorly developed sternum

Question 15

archaeopteryx bird like character

Answer 15

feathers and wings (used winds to catch food)

Question 16

structure of what 3 things indicates a bird’s diet (other habits)

Answer 16

1. bill
2. feet
3. wings (e.g.penguin wings are specialised for swimming and inappropriate for flight)

Question 17

flightless birds have 2 things

Answer 17

1. small wings

2. small flight muscles

Question 18

birds that are bipedal runners have

Answer 18

strong, muscular legs e.g. ostrich

Question 19

4 key adaptations of mammals

Answer 19

1. high metabolic rate and temperatures
2. specializations of teeth and jaws
3. parental care
4. complex brains-cerebral cortex

Question 20

1. high metabolic rate and temperatures of mammals adaptations include (3)

Answer 20

• 4 chambered heart and complex circulatory systems deliver oxygen
• diaphragm
• fur and insulating fat

Question 21

2. specializations of teeth and jaws of mammals adaptations include

Answer 21

allow mammals to feed efficiently (CAN CHEW) - mammals have 4 types of teeth

1. incisors
2. canines
3. premolars
4. molars

Question 22

3. parental care of mammals adaptations include (2)

Answer 22

1. uterus and placenta

2. mammary glands

Question 23

4. complex brains of mammals adaptations include (2)

Answer 23

cerebral cortext, part of the forebrain responsible for info processing and learning

• strongly influences behaviours
• associated with sense of smell

Question 24

2 main groups of modern mammals

Answer 24

1. prototheria (monotremes)

2. theria (live bearing)

Question 25

2 types of theria (live bearing)

Answer 25

1. metatheria (marsupials)

2. eutheria (placentals)

Question 26

2 differences of marsupials and placentals

Answer 26

Marsupials :

• short pregnancy (<2 weeks)
• complete embryonic development in mother’s abdominal pouch (marsupium)

Placentals

• longer pregnancy (3 weeks- 2years)
• complete embryonic development in mother’s uterus -nourished through placental