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NEXT WEEK IN BIO153

!  Tuesday: Lecture 19: Human evolution

!  Thursday: Lecture 20: Intro to ecology

! Friday: Good Friday - no tutorial 

! Readings: Chapter 34

! No labs

!  Assignment 3 due Mar. 24

Session ID:l|c

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 TUTORIAL 9:

EVOLUTION OF THE DOMESTIC DOG How did Darwin study artificial selection?

 How fast did domestic dogs evolve and how did they change?Can we experimentally test hypotheses about dog evolution?

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DOGS CLEARLY WERE AND ARE IMPORTANT TO PEOPLE

 Dogs of King Antef from Egyptian

relief (2323 BC. to 2134 BC).

Cave painting from ??

     h    t    t    p   :     /     /     b     l   o   g .     b

     l   a   n    t   o   n   m   u   s   e   u   m .   o   r   g     /     f     i     l   e   s     /

     2     0     1     2     /     0     1     /     C   a   v   e  -    p   a     i   n    t     i   n   g .     j

    p   g

Gaston Phebus, illustration from Le Livre

de la chasse (The Book of Hunting), 14th- 15th centuries, illuminated manuscript

RANDOM NOTETullimonstrum gregarium was a vertebrate, all vertebrates are chordates

- fossil evidence of its gut, has to do with the structure of how both theseorganisms fossilize, 3-dimensional element to its fossilization,-https://www.theguardian.com/science/2016/mar/18/tully-monster-mystery-of-the-300-million-year-old-fossil-finally-solved

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DOGS WERE THE FIRST DOMESTICATED SPECIES

Domesticated from gray wolves over 15,000 years ago, probablyin several locations

Canis lupus Canis lupus familiaris

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WE STILL HAVE QUESTIONS ABOUT DOMESTICATION AND DOGS

 

1. What changes occur during domestication?

 

2. How quickly could domestication occur?

 By fugzu - originally p osted to Flickr a s Cody alias Fez delle Caseross e, CC

 BY 2.0, https://c ommons.wikimedi a.org/w/index.php? curid=32932031

2-stage process, where wolves approached the human sediments and became to rely onthem, and human began to give them large chunks, encouraging them-and then the process of artificial selection began (on the dogs brave enough toapproach humans)

so 1) approach human sediments 2) artificial selection

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DARWIN USED DIFFERENT SOURCES OF DATA TO SUPPORT HIS THEORY

! Examples of adaptation,

! Structural homology,

!  The fossil record, and

! Biogeography,

! Domesticated species

Why do you think domesticated species

would be an important part of his theory?Darwin did not know about Medellian genetics- he can show that species can change- the fact that the traits were heritable, and artificial selection showed him that thetraits were indeed heritable, so then artificial selection and domestication showed himthat if you select for a trait in a population it will appear in subsequent generations,allowed him to make his arguments without understanding how it actually works(Mendellian genetics)

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ARTIFICIAL SELECTION IS THE SELECTIVE BREEDING OF DOMESTICATED SPECIES

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DARWIN ALSO NOTED OTHER CHANGES IN ARTIFICIALLY SELECTED ANIMALS

! Drooping ears

! piebald coloration, forehead

star

!

wavy hair! rolled, shorter tails

! changes in reproductive cycles

What does this mean?

don't see commonly in wild populations

if we didn't select for these traits why do they appear?- maybe the gene that we select for lies close to the one we're not-linked genetically to those traits we are selecting for, that' why they're showing up

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WE STILL HAVE QUESTIONS ABOUT DOMESTICATION AND DOGS

 

1. What changes occur during domestication?

 

2. How quickly could domestication occur?

 By fugzu - Flickr: raskal, CC BY 2.0, https:// commons.wikimedia.org/w/index.php?curid=31447186

we need variation for a.s. to work, large population with a lot of diversity so wecan actually choose, look for those that are least aggressive - selections based ona behavioural trait

- what's ur hypothesis then?

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DR. BELYAEV BEGAN A STUDY ON FOX DOMESTICATION IN 1959

http://scienceblogs.com/thoughtfulanimal/2010/06/14/monday-pets-the-russian-fox-st/ 

expect to see friendlier foxes in 2016-look slightly different too/ change the morphology

-

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WHAT WOULD YOU DO?

Suppose you had a fox farm with a large diverse population ofanimals available for you to study.

! Design an experiment you would conduct to see if you could

“re-create” dog domestication and investigate the genetics of

tameness using foxes.

! What is your hypothesis and what would you expect to

observe? Explain.

! How would your experiment further our under- standing ofdog domestication? Domestication in general?

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HERE IS WHAT BELYAEV DID

! Fox pups (called kits) from the population were scored fortameness and assigned to classes:

! Class 3: flee or aggressive response to experimenter

!

Class 2: allow petting but no emotional response toexperimenter

! Class 1: friendly to experimenter (wag tail, whine, etc.)

! Next, scientists bred the most friendly Class 1 foxes (Elite

Class 1 = E1) over many generations.

! What would you expect?

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 THESE ARE THE FOXES TODAY!

http://ngm.nationalgeographic.com/2011/03/taming-wild-animals/musi-photography

clearly they are domesticated!!this was just about 60yrs

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 THE RESULTS

Generation % E1 Kits

10 18

20 35

35 70-80

by 35 generations u almost have a completely domesticated litter

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 THE RESULTS

CharacteristicUndomesticatedanimals with trait

(per 100,000)

Domesticatedanimals with trait

(per 100,000)

Frequency increase(%)

Star on forehead   710 12,400 1646

Mottled fur   86 450 423

Floppy ears   170 230 35

Shortened tail   2 140 6900

Curled tail   830 9400 1033

didn't select for this

all these genes are linked to the behavioural ones we selected for

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WHAT DO YOU EXPECT?

eyes fully open response window of

to sound socialization

DOGS

WILDFOXES

DOMESTICATEDFOXES

7 8 9 10 11 12 13 14 15 16 17 18 19 4 6 8 10 12

DAYS WEEKS

(Trut, 1999)

care is provided by humans so mother fox not needed

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IN THIS CASE STUDY, WE …

! described artificial selection and how it relates todomestication.

! showed how genetic variation, inheritance, and selection can

result in phenotypic changes and adaptation in a lineage or

population over time.

! demonstrated that selection on one trait can lead to changes in

other traits.

!

developed hypotheses to investigate an identified question.! predicted outcomes of experiments.

! analyzed data and interpret experimental results in light of

research results.

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NEXT LECTURE PERIOD

 Lecture 19: Human evolution