day 18 october 26th chapters 8 and 9 scribd

8/3/2019 Day 18 October 26th Chapters 8 and 9 Scribd

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Day 18 October 26th Chapters 8

and 9

If you need to talk to me about the

youtube assignment, we can meetafter class in my office.



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

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

experiments and observations.



Changes in the Frequencyof the Various Alleles



In the laboratory, the

farm, the doctor’soffice, the bathroom

sink, the deserts,streams, and forests,

evolution is

occurring.



Animals should maximize energy consumedand minimize energy used.

1) Behavior hasadaptive value

just like othertraits.



Humans show an aversion to eating dirt



Humans like to eat foods high in fat andsugar.

humans prefer sweet, but not too sweet



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



Effects of evolution by natural selection areall around.

Peacock feathers

Cryptic coloration observed in many

species

BEHAVIOR is part of an organism’s

phenotype.• also under the influence of natural selection



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

Instincts or innatebehaviors

Fixed action pattern

Role of the Environment



Triggered undercertain conditions

Requires nolearning

Does not vary

Once started, runsto completion

Fixed Action Pattern



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



Prepared Learning

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

Snake-fearing behavior of monkeys

Acquisition of language in humans



Animals don’t consciously try tomaximize their reproductivesuccess, yet they behave as if

they do?

How do they do it?



Rules of Thumb

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



Rules of Thumb

Pleasures, incentives, and reproductivesuccess

Not necessary for the animal to beconsciously seeking that outcome



How do we

know?

Tricking animals



9.5 A general theory of “kindness” helps explain the evolution of apparent acts of altruism.

Does unconditional love exist in the animalkingdom?

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



Darwin

Natural selection generally works toproduce selfish behavior.

Altruistic-appearing behavior is common.

Fatal to his theory?



Apparent Acts of Altruism

Kindness toward close relatives: kinselection

Kindness toward unrelated individuals:reciprocal altruism



Hamilton’s 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 .

day 18 october 26th chapters 8 and 9 scribd

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