day 16 march 20th chapter 8 and 9

8/2/2019 Day 16 March 20th Chapter 8 and 9

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Day 16 March 20th

Chapters 8 and 9

400 million years between humans

and our fish ancestors


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How many generations do you think

there are between humans and our

fish ancestors?

1. Tens

2. Hundreds

3. Thousands

4. Millions


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How many generations do you think

there are between humans and our

fish ancestors?

1. Tens

2. Hundreds

3. Thousands

4. Millions


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What made humans different?

Moved from inland

Africa to the shores

Collected shellfish, ate

fish (DHA) Your brain is mostly

composed of fat!

Mammals haveplacenta

Mammals drink milk


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http://evolution.berkeley.edu/evolibrary/news/060201_zebrafish
http://evolution.berkeley.edu/evolibrary/news/060201_zebrafishhttp://evolution.berkeley.edu/evolibrary/news/060201_zebrafish


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Five primary lines of evidence:

1. The fossil record

2. Biogeography

3. Comparative anatomy and embryology

4. Molecular biology

5. Laboratory and field experiments


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8.17 The fossil record

documents the process ofnatural selection.

Although it has been central to much documentation of the

occurrence of evolution, it is a very incomplete record


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8.19 Comparative anatomy andembryology reveal common

evolutionary origins.


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Ernst Haeckel (1834-1919)


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Chick embryos and human embryos bothhave gills because

1. They both need to breathe through thegills (while in the egg and placentarespectively) during development.

2. They both spend some time in the waterwhere gills are useful.

3. They both share a common ancestorwho had gills.

4. 1 and 3.


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Chick embryos and human embryos bothhave gills because

1. They both need to breathe through thegills (while in the egg and placentarespectively) during development.

2. They both spend some time in the waterwhere gills are useful.

3. They both share a common ancestorwho had gills.

4. 1 and 3. NO!!! They receive oxygenthrough the umbilical cord!


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Homologous Structures


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Similarities common ancestor

Differences adapted to environment

For example, look at the hands offour primates: tarsier, gibbon,chimpanzee, and human. Despite thesimilarities in their hands, thedifferences are what makes eachmost suitable for its way of life. The

tarsier leaps and clings, and has largefinger pads to help it do this. Thegibbon swings from the trees, so haslong, strong fingers for swinging. Thechimpanzee may be able tomanipulate very crude tools with itsstubby thumb, but the humans

thumb faces the forefinger, whichprovides dexterity for countlesspurposesfrom threading a needleto mountain climbingfrom carvingwood to buttoning a shirt.


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A human forearm, horses front leg, bats wing, andporpoises flipper have similar bone structure. What

conclusions can we draw from the similarities in bone

structure between these mammals?

1. Since each limb is used for different functions, these speciesmust be unrelated evolutionarily.

2. Since each limb has a different shape, these species mustbe related evolutionarily.

3. Since each limb shares the same type of bone structure but

performs different functions, these structures are theproduct of adaptive evolution.

4. Since each limb shares the same type of bone structure butperforms different functions, these species cannot possibly

be related evolutionarily.


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A human forearm, horses front leg, bats wing, andporpoises flipper have similar bone structure. What

conclusions can we draw from the similarities in bone

structure between these mammals?

1. Since each limb is used for different functions, these speciesmust be unrelated evolutionarily.

2. Since each limb has a different shape, these species mustbe related evolutionarily.

3. Since each limb shares the same type of bone structure but

performs different functions, these structures are theproduct of adaptive evolution.

4. Since each limb shares the same type of bone structure butperforms different functions, these species cannot possibly

be related evolutionarily.


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The human appendix serves nofunction.

Why are we all born with one?


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Vestigial Organs

A vestigial organ is a part of the body that serves no use. The

appendix is one example of a vestigial organ; wings on an ostrichare another. The human body has several vestigial organs,

including the tail bone, wisdom teeth and muscles in the ear.


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Vestigial Structures


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Convergent Evolution

Analogous structuresall developed fromdifferent original

structures.


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8.20 Molecular biology revealsthat common genetic sequences

link all life forms.The genetic code provides our fourthline of evidence that evolution occurs.


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DNA Similarities and Differences

Related vs. unrelated individuals

The more distantly you and anotherindividual are related, the more your DNAdiffers.


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Scientists ask the questionDoes

race exist?

The Human Genome Project

found all humans to have a

99.9 % similar geneticcontent and identity, but this

is challenged by a new more

detailed research suggesting

a higher genetic diversity,with further medical and

evolutionary implications.


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DNA Similaritybetween Two Species

Compare their DNA sequences forindividual genes.

In Rhesus monkeys, 138 amino acids outof 146 are the same as those found in

human hemoglobin.


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Recency of Common Ancestry

Estimates of evolutionaryrelatedness made from:

Comparative Anatomy

Embryology The Fossil Record

Molecular Clocks


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8.21 Laboratory and field experimentsenable us to watch evolution in progress.

A fifth line of evidence for the occurrence ofevolution comes from multigeneration

experiments and observations.


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Changes in the Frequencyof the Various Alleles


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What do you think? Understanding evolutioncan help scientists find strategies to combat

antibiotic and pesticide resistance.

1. Strongly agree

2. Agree3. Neutral

4. Disagree

5. Strongly disagree


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Chapter 9


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Animals should maximize energy consumedand minimize energy used.

1) Behavior hasadaptive value

just like othertraits.


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Humans show an aversion to eating dirt


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Humans like to eat foods high in fat andsugar.

humans prefer sweet, but not too sweet


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The arrow on the graph below mightrepresent which food source?

1. Doughnut

2. Saltines

3. Carrot

4. Hamburger

humans prefer sweet, but not too sweethumans prefer sweet, but not too sweet


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The arrow on the graph below mightrepresent which food source?

1. Doughnut

2. Saltines

3. Carrot

4. Hamburger

humans prefer sweet, but not too sweethumans prefer sweet, but not too sweet


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Why do species have taste preferences?

Feeding choices directly influence fitness.

Living and reproducing requireenergy.

Maximal extraction of energy andacquisition of essential nutrients

Natural selection can shape feedingbehavior.


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Behaviors can be influenced by naturalselection.

Feeding behavior

Humans; starlings; shore crabs examples

Maternal care

Mice example neglectful gene

Singing behavior

Songbirds example complex songs


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Effects of evolution by natural selection areall around.

Peacock feathers

Cryptic coloration observed in many

species

BEHAVIOR is part of an organisms

phenotype. also under the influence of natural selection


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Which characteristic below will be under the

influence of natural selection in nature?

1. A warblers song

2. Food preferences

3. Care of offspring

4. Male or female attractiveness

5. All of the above


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Which characteristic below will be under the

influence of natural selection in nature?

1. A warblers song

2. Food preferences

3. Care of offspring

4. Male or female attractiveness

5. All of the above


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The degree to which abehavior dependsupon the environmentvaries a great deal.

Instincts or innatebehaviors

Fixed action pattern

Role of the Environment


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Triggered undercertain conditions

Requires no

learning

Does not vary

Once started, runsto completion

Fixed Action Pattern


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Do you think humans have innate(fixed action) behaviors?

1. Strongly agree

2. Agree3. Neutral

4. Disagree

5. Strongly disagree


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Learning

Involves behaviors that are altered andmodified over time in response to pastexperiences

Tremendous variation among behaviorsthat require learning

Some are easy to learn

Others are not


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Prepared Learning

Behaviors that are learned easily and by all(or nearly all) individuals

Snake-fearing behavior of monkeys

Acquisition of language in humans


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Animals dont consciously try tomaximize their reproductivesuccess, yet they behave as if

they do?

How do they do it?


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Rules of Thumb

Relatively easy-to-follow responses to cuesthat reliably lead to a desired outcome


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Rules of Thumb

Pleasures, incentives, and reproductivesuccess

Not necessary for the animal to beconsciouslyseeking that outcome


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How do we

know?

Tricking animals


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9.5 A general theory of kindnesshelps explain the evolution ofapparent acts of altruism.

Does unconditional love exist in the animalkingdom?

Altruistic behaviorsbehaviors thatcome at a cost to the individual doing thebehavior while benefiting the recipient.


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Darwin

Natural selection generally works toproduce selfish behavior.

Altruistic-appearing behavior is common.

Fatal to his theory?


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Apparent Acts of Altruism

Kindness toward close relatives: kinselection

Kindness toward unrelated individuals:reciprocal altruism


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Hamiltons Rule

Altruistic-appearing behavior will occurwhen the benefits to close relatives aregreater than the cost to the individual

performing the behavior.

They are really acting in their own

genes best interests.


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According to Hamiltons rule, if anindividual could only help oneperson, who would they prefer tohelp?

1. Son with a flat tire

2. Aunt with a flat tire

3. Cousin with a flat tire4. Stranger with a flat tire


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According to Hamiltons rule, if anindividual could only help oneperson, who would they prefer tohelp?

1. Son with a flat tire

2. Aunt with a flat tire

3. Cousin with a flat tire4. Stranger with a flat tire

day 16 march 20th chapter 8 and 9

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