Chapter 52

Behavioral Biology

Innate behavior

Some behaviors are “preprogrammed” into the nervous system

Triggered by a stimulus - can vary

Other examples??

Proximate causation defines how something works…

Ultimate causation discusses why it works!

Behavioral genetics

Take the “rats in a maze”…– Some learn faster than others to get the

cheese– Genetic superiority??

Can also witness differences between identical twins!– Some say nature over nurture, but what

about twins separated at birth who lead “parallel” lives?

– Creepy??

Some behavior is learned…

Touch a hot flame, learn to stay away from fire!

Salivation at the sound of a bell…example of _____?

Trial and error to get a desired result… Some are simply due to the biology of the

animal. – Now have I.D.ed specific genes that may govern

behavior

Learning influences behavior

When we learn, we change our behavior to reflect that learning

Some are not stimulated (habitual) and some require an association between a stimulus and a response. Ex: Pavlov

Instinctual learning - biologically influenced - goes back to evolution…– Burying seeds and remembering where to find

them = larger memory center in the brain of those animals who exhibit this behavior

Parent-Offspring interactions

Most behavioral biologists recognize that behavior is both learned and genetic

We imprint on our parents to a degree - this may influence some decisions later in life

Other animals may imprint on the first thing they see!

Genetically, animals may be attuned to certain songs, sound, or smells that guide them to the correct species:– Ex: Cuckoos - have pre-programmed songs for their

species even though they are raised by others

Migratory Behavior

Taxis - moving toward or away from a stimulus

ex: moths to light Kineses - changing activity

in response to an increasing stimulus

Animals who migrate use the stars, sun, landmarks, and magnetic fields to navigate Ex: monarchs, geese, sea turtles– Others?

Communication

Some species have distinct sounds

Pheremones Levels of

specificity - to make the individual stand out

Social animals sometimes have designated individuals to carry out specific jobs

~ honeybees - guards, drones, queen ~ other examples? Language among higher animals -

primates in particular - help convey meaning to others in the group

Evolution shapes behavior

Behavioral ecology - study of how natural selection shapes behavior

~ after a baby bird hatches, the parents often remove the shell to reduce predators seeing the broken shell and eating the offspring - is adaptive

Is all behavior adaptive? – Not necessarily…can be caused by genetic drift,

gene flow, or consequences of conscious selection– Could also be past adaptations that evolved and are

no longer useful!

Examples of behaviors…

Foraging - looking for food and weighing the cost of finding it with the amount of reward at the end

~ must be energy efficient to be productive - max input per foraging time

Territorial - defend your ground against predators and intrusion!

Reproductive Strategies - benefit of choosing this mate over that one…– Parental investment - each sex makes a different

contribution to making and rearing offspring– Vary greatly among species!

• Different mating systems• Sexual selection for those that are genetically desirable

Evolution of social behavior?

Altruistic - benfits one while costing the one who is helping

* Seen in lions - all cubs nurse from more than just the mother

Reciprocity - “you scratch my back and I’ll scratch yours”

Social animals are more likely to behave in a way to protect their kin if they have a higher number of related members in the group– ~ ie - if a mother has many children

in a group, she will act to protect them more than if she was a “aunt” to those children

Haplodiploidy

Bees have distinct roles within the social group

~ members are of differing sizes and abilities

~ do not stray from their roles

~ males are haploid, females diploid

~ eusocial system

Vertebrate systems are less organized and are less altruistic

Usually kin selected altruism

So which is evolutionarily more advanced???

Still up for debate!