Biological Basis of BehaviorBiological Basis of Behavior

Biological RhythmsBiological Rhythms Neural Centers (Brains)Neural Centers (Brains) HormonesHormones

Control Animal Behaviors

Biological Basis of BehaviorBiological Basis of Behavior

Biological RhythmsBiological Rhythms– Circadian rhythms Circadian rhythms

24 hours of chemical activity – controls sleep and 24 hours of chemical activity – controls sleep and wakefulnesswakefulness

The same gene controlling our 24 hour “clock” is The same gene controlling our 24 hour “clock” is found in animals ranging from fruit flies to hamsters found in animals ranging from fruit flies to hamsters to humansto humans

Migration and Circadian RhythmsMigration and Circadian Rhythms

Animals migrating long distances use the Animals migrating long distances use the position of the sun AND the time of day position of the sun AND the time of day (circadian rhythm) to know where they are.(circadian rhythm) to know where they are.

It is a built-in GPS device!It is a built-in GPS device!

Studies on Circadian Rhythms with Studies on Circadian Rhythms with HumansHumans

Experiments Experiments – Subjects = blind individuals and sighted Subjects = blind individuals and sighted

individualsindividuals– In a light controlled environment, both groups In a light controlled environment, both groups

displayed cycles very close to 24 hours. displayed cycles very close to 24 hours.

Studies on Circadian Rhythms with Studies on Circadian Rhythms with HumansHumans

Surveys and ExperimentsSurveys and Experiments– Early morningEarly morning people and people and late morninglate morning

people – have different levels of chemical people – have different levels of chemical activity during the day. activity during the day.

Circadian Rhythms and YouCircadian Rhythms and You

- Decide by yourself if you are an early Decide by yourself if you are an early morning, late morning or an evening person.morning, late morning or an evening person.

- Take a survey and find out for sure!Take a survey and find out for sure!

Circadian rhythmsCircadian rhythms

Example of Circadian rhythms in Example of Circadian rhythms in – House House Mouse – Aggressive behavior vs. – Aggressive behavior vs.

Parental behaviorParental behavior

House MouseHouse Mouse

Natural conditionsNatural conditions– Male copulates with femaleMale copulates with female– After copulation the male becomes highly After copulation the male becomes highly

aggressive to mouse pups—killing any he finds.aggressive to mouse pups—killing any he finds.

What is the evolutionary cause of this behavior? (In other words—what makes this behavior an adaptation—something that improves survival?)

House MouseHouse Mouse

Natural conditionsNatural conditions– Aggressive behavior lasts 21 daysAggressive behavior lasts 21 days– Between 3 -7 weeks the male is protective of all Between 3 -7 weeks the male is protective of all

mouse pups he comes across.mouse pups he comes across.– At 7 weeks the male copulates again and the At 7 weeks the male copulates again and the

cycle restarts. cycle restarts.

What is the evolutionary cause of this behavior?

House MouseHouse Mouse

Lab studyLab study– Scientists shift mouse “clock” by changing Scientists shift mouse “clock” by changing

length of light/dark exposure.length of light/dark exposure. Mice exposed to 22 hour cycles of light/dark (short Mice exposed to 22 hour cycles of light/dark (short

days) OR days) OR Mice exposed to 27 hour cycles of light/dark (long Mice exposed to 27 hour cycles of light/dark (long

days)days)

House MouseHouse Mouse

Lab studyLab study– ““Short day” mice are exposed to pups on the Short day” mice are exposed to pups on the

2020thth REAL day (but their REAL day (but their 2222ndnd day).day).

Consider: Consider:

How should a male mouse behave How should a male mouse behave towards pups on the 20towards pups on the 20thth day after day after

copulation? copulation?

How should a male mouse behave How should a male mouse behave towards pups on the 22towards pups on the 22thth day after day after

copulation? copulation?

House MouseHouse Mouse

The results:The results:– Males were tricked into “thinking” that it was 22 Males were tricked into “thinking” that it was 22

days after copulation. days after copulation. – Males were NOT aggressive to mouse pups!!Males were NOT aggressive to mouse pups!!

House MouseHouse Mouse

Lab studyLab study– ““Long day” mice are exposed to pups on the Long day” mice are exposed to pups on the

2222ndnd REAL day (but their REAL day (but their 1919thth day).day).

– Males show aggression to pups!Males show aggression to pups!

What happens? How do the male mice What happens? How do the male mice act towards the pups?act towards the pups?

Circannual rhythmsCircannual rhythms

One year cycle of chemical activityOne year cycle of chemical activity– Examples: time to Examples: time to

FeedFeed HibernateHibernate ReproduceReproduce Etc. Etc.

In most cases, these behaviors are In most cases, these behaviors are environmentally independent. environmentally independent.

Circannual rhythmsCircannual rhythms

Example of Circannual rhythms in Example of Circannual rhythms in – Golden Mantled Golden Mantled Ground Squirrel and and

hibernationhibernation

Golden Mantled Ground SquirrelGolden Mantled Ground Squirrel

Lab StudyLab Study– Squirrels blinded at Squirrels blinded at

birth birth – Environmental Environmental

conditions kept the conditions kept the same throughout the same throughout the year: same year: same temperature, same temperature, same amount of food amount of food

Golden Mantled Ground SquirrelGolden Mantled Ground Squirrel

The squirrels entered The squirrels entered hibernation at the hibernation at the SAME TIME as its SAME TIME as its species in the wild species in the wild under changing under changing environmental environmental conditions!conditions!

Circannual RhythmsCircannual Rhythms

Read Turtle Article and

Answer Questions

Neural Command Centers a.k.a. Neural Command Centers a.k.a. BrainsBrains

A brain is the part of the nervous system A brain is the part of the nervous system that controls and coordinates the mental and that controls and coordinates the mental and physical actions of an animal physical actions of an animal

Vertebrates and invertebrates have brains. Vertebrates and invertebrates have brains. The only animal without a nervous system at The only animal without a nervous system at

all is the sponge. all is the sponge.

Invertebrate BrainInvertebrate Brain

Simple animal brains Simple animal brains – Small worms—a group of neurons (nerve cells) Small worms—a group of neurons (nerve cells)

acting together = brainacting together = brain If an earthworm is touched, the stimulus is detected If an earthworm is touched, the stimulus is detected

by receptor cells in the skinby receptor cells in the skin The receptor cells send a message via nerve cells to The receptor cells send a message via nerve cells to

the brain, where the information is interpreted.the brain, where the information is interpreted.

– Octopus –most complex invertebrate brainOctopus –most complex invertebrate brain

Read Article: Octopus Arms Found

to Have “Minds” of Their Own

The Vertebrate BrainThe Vertebrate Brain

Name the 5 groups of Vertebrates: Name the 5 groups of Vertebrates: ________________,________________, ________________,________________, ________________, ________________, ________________, ________________, ________________, ________________,

The brain is located at the anterior (= The brain is located at the anterior (= on or on or in the front end of the bodyin the front end of the body) of the spinal ) of the spinal cordcord

MammalsAmphibians Birds

ReptilesFish

BrainBrain

PartsParts– Cerebrum – controls voluntary or conscious Cerebrum – controls voluntary or conscious

activities of the body activities of the body – Cerebellum – coordinates the movement of the Cerebellum – coordinates the movement of the

bodybody– Medulla oblongata – controls the functioning of Medulla oblongata – controls the functioning of

many internal organs that do not involve any many internal organs that do not involve any conscious control (breathing and heart rate)conscious control (breathing and heart rate)

How the Brain WorksHow the Brain Works

Listen to Sebastian Listen to Sebastian Seung, professor of Seung, professor of computational computational neuroscience at MIT neuroscience at MIT on National Public on National Public Radio, Radio, February 17, 2012**

Read the Interview Read the Interview Highlights with Highlights with Professor SeungProfessor Seung

Fish and Amphibians BrainFish and Amphibians Brain

The anterior end of most brains contains The anterior end of most brains contains olfactory bulbs (smell) which is well olfactory bulbs (smell) which is well developeddeveloped

Reptile BrainReptile Brain

Similar to amphibian/fish brain. Cerebrum Similar to amphibian/fish brain. Cerebrum and cerebellum are larger when compared and cerebellum are larger when compared to the rest of the brain to the rest of the brain

Bird BrainBird Brain

Cerebrum—responsible for nest-building, Cerebrum—responsible for nest-building, care of young, courtship and mating—is care of young, courtship and mating—is large.large.

Cerebellum—responsible for controlling the Cerebellum—responsible for controlling the coordinated movements of flight—is large coordinated movements of flight—is large

Mammal BrainMammal Brain

Most highly developed brain of all animals.Most highly developed brain of all animals.– Contains: cerebrum, cerebellum, medulla Contains: cerebrum, cerebellum, medulla

oblongata AND oblongata AND – Cerebral cortex: outer layer of cerebrum—Cerebral cortex: outer layer of cerebrum—

center for thinking and other complex behaviorscenter for thinking and other complex behaviors

Hormonal SystemsHormonal Systems

Hormone — A chemical substance Hormone — A chemical substance produced in the body that controls and produced in the body that controls and regulates the activity of certain cells or regulates the activity of certain cells or organs. organs.

All vertebrates have hormones All vertebrates have hormones TestosteroneTestosterone – usually associated with – usually associated with

aggressiveness and sexual readiness in aggressiveness and sexual readiness in malesmales

HormonesHormones

1771 – England: 1771 – England: Scientist transplanted Scientist transplanted a rooster’s (male a rooster’s (male chicken) testes (where chicken) testes (where testosterone is testosterone is produced) into a hen produced) into a hen (female chicken) and (female chicken) and found she grew found she grew rooster-like combs and rooster-like combs and wattles. wattles.

HormonesHormones

• In 1849, a scientist transplanted testes from In 1849, a scientist transplanted testes from a normal rooster into a castrated rooster. a normal rooster into a castrated rooster. The castrated rooster regained his combs The castrated rooster regained his combs and wattles, his crowing voice, and his and wattles, his crowing voice, and his fighting behavior. fighting behavior.

HormonesHormones

Estrogen – Usually associated with female Estrogen – Usually associated with female reproduction and parental behaviorreproduction and parental behavior

Often hormones act together with circannual Often hormones act together with circannual rhythmsrhythms– The level of testosterone in male mice The level of testosterone in male mice

increases after mating and stays high for three increases after mating and stays high for three weeks. The testosterone level drops on the weeks. The testosterone level drops on the 2222ndnd day after mating and remains low for 4 day after mating and remains low for 4 weeks. weeks.

Hormones and LizardsHormones and Lizards

Sexual behavior of an AnoleSexual behavior of an Anole– Anoles spend the winter under a rockAnoles spend the winter under a rock– January – males emerge and establish breeding January – males emerge and establish breeding

territoriesterritories– May –females emerge and begin to lay May –females emerge and begin to lay oneone egg egg

every 10-14 days for 3 months (6-9 eggs) every 10-14 days for 3 months (6-9 eggs)

ExperimentExperiment

Question: How do the levels of hormones Question: How do the levels of hormones correlate with this activity?correlate with this activity?

Studies have found the levels of Studies have found the levels of testosterone in males is VERY HIGH in testosterone in males is VERY HIGH in early spring and then levels decrease.early spring and then levels decrease.

Studies have found the levels of estrogen in Studies have found the levels of estrogen in females is VERY HIGH in early spring and females is VERY HIGH in early spring and then levels decrease.then levels decrease.

ExperimentExperiment

Question – What causes this change to Question – What causes this change to happen? happen?

In lab: Females exposed to spring-like In lab: Females exposed to spring-like conditions (it was actually winter). They conditions (it was actually winter). They increased their estrogen levels and increased their estrogen levels and produced eggs. produced eggs.

This proved that hormone levels increased This proved that hormone levels increased based on __________ _____________based on __________ _____________environmental conditions

ExperimentExperiment

The experiment was repeated. Females The experiment was repeated. Females divided into:divided into:– Group A -- exposed to males Group A -- exposed to males – Group B -- exposed to only femalesGroup B -- exposed to only females

Group A produced eggs more quickly than Group A produced eggs more quickly than Group BGroup B

Conclusion: Hormone production is Conclusion: Hormone production is increased by two types of stimulation– increased by two types of stimulation– springlike conditions springlike conditions ++ presence of males! presence of males!

Biological Basis of BehaviorBiological Basis of Behavior

Biological RhythmsBiological Rhythms Neural Centers (Brains)Neural Centers (Brains) HormonesHormones

Control Animal Behaviors