Week 10

Question 1

What is domestication

Answer 1

Domestication is a sustained multi-generational relationship in
which one group of organisms assumes a significant degree of
influence over the reproduction and care of another group to
secure a more predictable supply of resources from that second
group.

Question 2

Name the differences between taming and domestication

Answer 2

Domestication of animals should not be confused with taming.
Taming is the conditioned behavioral modification of an individual animal, to reduce its natural avoidance of humans, and to tolerate the presence of humans. Domestication is the permanent genetic modification of a bred lineage that leads to an inherited
predisposition to respond calmly to human presence

Question 3

Name features of domestic organisms

Answer 3

1. Morhphologically unique: different in appearance from wild relatives.
2. Exist only in cooperation with humans (possibly with some feral – escaped – exceptions)
3. Genetically disposed to be tolerant and/or accepting of humans – will pass this trait on to their offspring.
4. Have been artificially selected for useful or attractive traits through at least some portion of their history
5. Serve a specific and obvious purpose – even if that purpose is decorative or to provide companionship.

Question 4

What questions do phylogenies answer ?

Answer 4

It answers questions about the process of evolution

Question 5

What are the 3 small bones found in the middle ear of the mammal

Answer 5

The ossicles

Question 6

What do the ossicles do ?

Answer 6

These bones transmit sound from the eardrum, which vibrates as sound reaches it, to the inner ear, where the information is transmitted to the brain.

Question 7

Name the 3 auditory ossicles

Answer 7

Malleus - “Hammer”
Incus - “Anvil”
Stapes - “Stirrup”

Question 8

What animal did mammals evolve from and which clade ?

Answer 8

Recall that mammals evolved
from from tetrapods (four-feet),
particularly a clade called the
synapsids.

Question 9

Which bone were the ossicles once a part of ?

Answer 9

The ossicles were once part of the jaw in synapsids.

When we are developing in the womb, the ear bones are actually part of the lower jaw as well!

Question 10

How are monotreme and therian ear bones an example of convergent evolution

Answer 10

The ossicles evolved independently in different lineages due to a common selection pressure – this is the same mechanism (cause) that we see in convergent evolution.

Sugar gliders are marsupials (have pockets) and flying squirrels are placental mammals – so the relationship here is similar!

Question 11

Explain some characteristics of the caudipteryx

Answer 11

Caudipteryx, a peacock-sized dinosaur (illustrated) that lived about 125 million years ago, was a fast runner.

The jostling from its gait may have caused its feathery forelimbs to flap, in a possible precursor to active flapping

Question 12

When did archaeopteryx get discovered and what did it look like ? Name characteristics

Answer 12

Archaeopteryx was discovered in 1861, showing what appeared to be a cross between a bird and a reptile.

Bird :
-Feathers
-Hollow skeleton with fused arm
bones.

Reptile :
-Teeth
-Claws on wings
-Long, flexible, reptilian tai

Question 13

Name some of the uses feathers had before flight

Answer 13

They were used to signal for mating displays and nesting

Question 14

Name a rule of natural selection

Answer 14

Every transitional trait must
be beneficial in order to increase in
frequency (how common it is) and
continue to undergo selection.

Question 15

How did dinos take off

Answer 15

Flapping motions helped feathered dinos run up steep inclines, like trees, to escape predation.

Question 16

What are most recent phylogenies based on

Answer 16

Molecular similarities
(ex; similarities of mitochondrial DNA sequences)

Question 17

Compare morphological comparisons of wolves and dogs

Answer 17

• Dogs tend to have curled tails, wolves have straight tails.
• Dogs tend to have smooth short coats.
• Skull shape differs.

Question 18

Molecular comparisons of wolves and dogs

Answer 18

*Gray wolves and dogs differ by no more than 0.2% in their mtDNA sequence.
* In contrast, gray wolves and coyotes differ by at least 4%.

Question 19

What are the 2 hypotheses of how dogs evolved from wolves

Answer 19

1) Ancestral wolf pups were domesticated
intentionally by early humans – Artificial selection.

2) Ancestral wolf populations experienced
natural selection forces that favored doglike characteristics.

Question 20

Name arguments for and against the hypothesis that ancestral wolf pups were domesticated intntionally by early humans

Answer 20

• Arguments for
  – It makes intuitive sense that ancestral wolves could be domesticated easily since they are so dog-like. Early humans would have intentionally bred ancestral wolves.
• Arguments against
  – Why would any human want to deal with an animal that avoids humans?
  – Modern wolves cannot be “domesticated” by training alone. It takes intensive and sophisticated selective breeding.

Question 21

Name the arguments for the hypothesis that ancestral wolf populations experienced natural selection forces that favored dog like characteristics

Answer 21

• Canids are very resourceful & would have found human waste piles good foraging – wolves were living close to humans.
• Wolves are shy, skittish animals – only “adventurous” wolves would have stayed close to the waste piles while humans were around.
• The “adventurous” wolves were the best fed and hence had high fitness.

Question 22

What is fitness in the evolutionary sense

Answer 22

Being ablet o survive and reproduce more successfully than others

Question 23

What characteristic is being selected for in the ancestral wolf population under the hypothesis about natural selection

Answer 23

Behaviours that lead to tolerance of humans being around

Question 24

What did the first dogs give humans that is the most significant in evolutionary terms

Answer 24

An early warning system that someone or something was approaching

Question 25

What trait did dogs gradually develop in terms of manipulation

Answer 25

The muscles required to raise the eyebrows exist in
dogs, but not in wolves, which have a small tendon
instead.

Dogs gradually developed the anatomy underlying
this communicative ability in response to human preference across tens of thousands of years.

Siberian Huskies, one of the oldest breeds, have only one of the two required muscles.