Lecture 35 Evolution & Domestication - Horses

Question 1

Evolution of the horse is reflected in their

Answer 1

-limbs
-teeth

Question 2

Majority of horse species evolved in

Answer 2

North America

Question 3

Horses, donkeys, and zebras are in the genus

Answer 3

Equus

Question 4

Evolution (names) of the Horse

Answer 4

Eohippus —> Oligohippus —>Merychippus —> Pliohippus —> Modern Horse

Question 5

Oldest known ancestor of the horse is

Answer 5

Eohippus (Hyracotherium)

Question 6

Hyracotherium (Eohippus) facts (6):

Answer 6

-oldest known ancestor
-fox-sized
-omnivore (3 incisors, 1 canine, 4 premolars, 3 molars)
-feet padded with small hoof like structures in place of nails
-forelimb digits 2-5 weight bearing, digit 1 vestigial
-hindlimb digits 2-4 weight bearing, digits 1 and 5 vestigial

Question 7

Orohippus facts (7):

Answer 7

-co-existed with Hydracotherium (Eohippus)
-pad footed
-forelimb had 4 digits
-hindlimb had 3 digits
-premolar 1 is smaller
-premolar 4 assumed shape/function of a molar
-crests on teeth more pronounced (grinding)

Question 8

Mesohippus facts (5):

Answer 8

-legs proportionally larger for running (forests became flatlands)
-3 digits on fore and hind limbs
-majority of weight on digit 3
-3 premolars more molar like (cheek teeth)
-more efficient grinding

Question 9

Miohippus facts (2):

Answer 9

-co-existed with Mesohippus but over time replaced them
-extra crest in upper molars (ie. equine teeth)

Question 10

Parahippus facts (4):

Answer 10

-size of small pony
-evolutionary link between ancestral forest horses and plain grazers
-3 digits, digit 3 larger, stronger, and weight bearing
-elongated skull

Question 11

Merychippus facts (3):

Answer 11

-milestone in evolution of horse
-retained primitive character of 3 digits
-high crowned check teeth for grazing (first known grazing horse)

Question 12

Horse teeth have

Answer 12

A large crown that continuously grows

Question 13

Pliohippus facts (4):

Answer 13

-similar appearance to Equus
-3 digits present but medial and later digits are vestigial stubs
-“grandparent” of modern horse
-gave rise to Dinohippus

Question 14

Dinohippus facts (1):

Answer 14

Closest relative to genus Equus

Question 15

Equus facts (3):

Answer 15

-only surviving genus of the horse family
-found on every continent except Australia and Antarctica
-two wild species

Question 16

Two wild species of Equus are

Answer 16

-Tarzan (Equus ferus ferus) now extinct
-Przewalski’s Horse (Equus ferus przewalskii)

Question 17

Equus caballus

Answer 17

Modern domestic horse

Question 18

Domestication of horses is debatable because (2)

Answer 18

-horses are extremely diverse
-horses are very widespread

Question 19

Genetic data has traced all domesticated horses to (2)

Answer 19

-one founder stallion
-at least 77 mares

Question 20

Domestication of the horse occurred

Answer 20

Twice

Question 21

In Botai culture in Kazakhstan, evidence of horse domestication is found (3)

Answer 21

1. metacarpals (cannon bone) found
2. Fatty lipids of horse milk found inside pots (horses kept for meat and milk)
3. Bit wear on horse teeth

Question 22

The horses domesticated in Botai are (2)

Answer 22

-not related to the modern horse
-gave rise to Przewalski’s horse

Question 23

Horse genome diversity has decreased due to (2)

Answer 23

-development of pure breeds
-decrease in draft breeds

Question 24

Myostatin gene is (3)

Answer 24

-the “Thoroughbred Gene”
-responsible for speed and precocity
-inhibits muscle cell growth

Question 25

SNP stands for __ and influences ___

Answer 25

Single nucleotide polymorphism; speed

Question 26

A horse with SNP with C/C is best suited for

Answer 26

Fast, short distance sprints

Question 27

A horse with SNP C/T is best suited for

Answer 27

Middle-distance races

Question 28

A horse with SNP T/T is best suited for

Answer 28

Long-distance races (greater stamina)