lab 2 comparative anatomy of mammals

Question 1

Key facts on Tasmanian tigers

Answer 1

1 - carnivores marsupials/thylacines extinct 1936. Driven to extinction by hunting.
2 - outwardly resemble wolves (convergent evolution) but belong to the same family as Tasmanian devils and quolls.

Question 2

Comparative Anatomy

Answer 2

Study of similarities and differences in anatomy of different species. Evidence for modification by descent. Classification based on similar characteristics. share common ancestor

Question 3

Analogy

Answer 3

Anatomical structures that serve similar functions but, as a result of convergent evolution, are not related. (homoplasy) e.g. legs on insects and vertebrates.

Question 4

Homology

Answer 4

Anatomical structures based on shared ancestry. E.g. chimps hands and Human hands (shared symplesiomorphy). Howeve, homologies can look different - divergent evolution. (Derived unique features autoapomorphies e.g. wings of bats and arms of primates.

Question 5

mammals

Answer 5

other than amphibians reptiles and birds mammals have 4 limbs (tetrapods) and are warm blooded. nourish young via milk secreting organs . 3 different groups.

Question 6

Monotremes

Answer 6

single common openings for urogenital and digestive systems. Young hatch as large yolky eggs. (duckbill platypus, echidnas or spiny anteaters.

Question 7

Marsupials

Answer 7

young born incompletely developed and suckle in pouch (e.g. Kangaroos, Tasmanian devils, opossums)

Question 8

Placentalia

Answer 8

pregnancy, foetus sustained through umbilical cord, placenta in womb e.g humans, rodents, primates

Question 9

major groups of primates

Answer 9

1 - lemurs (aye-aye, ring-tailed) and lorises.
2 - Tarsiers
3 - New World Monkeys - capuchins, spider monkeys
4 - Old World Monkeys - baboons, macaques.
5 - Apes i.e. small apes e.g. gibbons, great apes Chimpanzees, Gorillas, bonobos, and humans.

Question 10

Skulls of animals the can crush bones

Answer 10

hyenas - placentalia

Tasmanian devil - marsupial

Question 11

bodies of small burrowing invertebrate feeding mammals

Answer 11

European mole - placentalia
golden mole - placentalia
marsupial mole - marsupial

Question 12

mammals with continuously growing teeth

Answer 12

aye-aye - primate (placentalia)
Norway rat - rodent (placentalia)
1 - continuously growing teeth are absent in all primates but the aye-aye.

Question 13

Eyes with lenses

Answer 13

complex - evolved independently dozens of times.
curved sides of lenses are particularly efficient at concentrating light rays. e.g squids, jellyfish, snails bristle worms, and velvet worms.

Question 14

pendactyly

Answer 14

having 5 digits - digit 1 is thumb digit five pinky in tetrapods (four limbed vertebrates).

Question 15

wing structure in bats supported by which digits?

Answer 15

2-5th digit of hand

Question 16

which digits are elongated in the aye-aye?

Answer 16

all hand digits

Question 17

how many digits are preserved in dolphin fin?

Answer 17

5

Question 18

Recent horses are solid-hoofed. How many digits does the fossil in the display have?

Answer 18

3

Question 19

Which African animal of the Afrotheria clade of mammals don’t look like elephants but are close relatives?

Answer 19

Golden Moles elephant shrews, sea cows

Question 20

General primate traits

Answer 20

primate dentition is called heterodont because it is typically made up of incisors canines premolars and molars. - heterodonts have more diverse diets

Question 21

which types of animals have homodont dentitions?

Answer 21

crocodile, salmon, dolphin.

Question 22

in primates such as chimps macaques and capuchins which bones join the breast bone to with the shoulder blade?

Answer 22

Collar Bones/ clariculae

Question 23

What is the main function of this bone? T

Answer 23

To hold the arm freely and supported, away from the trunk. The shoulder is a rather freely moveable joint, and movements render it susceptible to dislocation. Preventing this is a main function of the collarbones.

Question 24

wing of flying lizard, how many hand digits? elongated or short

Answer 24

pterosauros - 4 hand digits 3 short and clawed 1 elongated