Mammals

Question 1

Skull fenestrae

Answer 1

Reduces weight, conserve calcium in the skull and makes room for muscle

Question 2

Three early amniotes

Answer 2

Anapsid, synapsid and diapsid

Question 3

Skull fenestrae in Anapsid

Answer 3

0

Question 4

Skull fenestrae in Synapsids

Answer 4

1

Question 5

Skull fenestrae in Diapsids

Answer 5

2

Question 6

Three extant lineages

Answer 6

Monotremes, Marsupials and Eutherians

Question 7

Monotremes

Answer 7

Egg laying
200 mya

Question 8

Marsupials

Answer 8

Pouched
100 mya

Question 9

Eutherians

Answer 9

Placental
100 mya

Question 10

Adaptive radiation

Answer 10

Increase in species from a single stem group

Question 11

Mammal characteristics

Answer 11

Vertebrae, 4 chambered heart, fur, mother produces milk, adaptations for reproduction, locomotion and thermoregulation

Question 12

Early mammals

Answer 12

Therians

Question 13

Extinction of dinosaurs

Answer 13

65 million years ago

Question 14

Common reproduction

Answer 14

Internal fertilisation
- fed by milk production as presence of mammary glands
- dependent on parental care

Question 15

Monotremes reporuction

Answer 15

Eggs fertilised in fallopian tube
Initial mucoid membrane - allows them to expand
Mineralised shell then applied and eggs are laid/incubated

Question 16

Reproduction monotremes - females

Answer 16

Embryo and extra embryonic membranes

Question 17

Reproduction monotremes - males

Answer 17

Testes lie in body cavity
But sperm stored in caudal epididymus (closer to the surface)

Question 18

Reproduction marsupials

Answer 18

Yolk sac placenta - not fully attached
Eggs fertilised in fallopian tube
Females have two vagina - medial birth canal forms between them
This may or may not re- separate afterwards

Question 19

Reproduction Eutherian

Answer 19

Well developed placenta
Longer gestation time - more efficient as precocial birth

Question 20

Placental functions

Answer 20

Anchors foetus to uterus
Transports nutrients from MC
Excretes metabolites to MC
Produces hormones to regulate organs in both
Suppress maternal immune response

Question 21

Eutherians vs marsupials

Answer 21

E = shorter offspring development means out reproduce for competition, this may be stressful on mother
M = can’t colonise in water

Question 22

Effects of body size on fertility?

Answer 22

large body = lower fertility in mammals

Question 23

Effects of timing on birth

Answer 23

shortening days - increase reproduction
lengthening days - repress reproduction

Question 24

Social reproductive suppression

Answer 24

• Behavioural
• stress induced
• pheromonal