Data-based question on p. 335:
1) In autumn, the length of the flights are generally shorter, usually around 1 to 2 hours long. The timing is also mainly right before sunset; there is no activity immediately before sunrise and most activity ends by 2100 (9 o’clock in the night).
a) There are usually multiple flights within the same day during the summer whereas in the autumn there is only one flight per day. Furthermore, there are three days in which flight activity lasts up until sunrise, whereas in the autumn all activity ends long before sunrise. One similarity is that for both summer and autumn, flight activity begins after sunset and ends before sunrise.
b) The reasons for the differences in behavior could be due to availability of food, which “varies over both space and time…[and requires change] to optimize food intake at any moment.” Another reason could be because mate selection occurs in the summer, thus bats have longer flight times in the summer than in the autumn.
3) The serotine bats show rhythmical variation over an annual because activity increases from spring to summer and decreases from summer to autumn. They also show rhythmical variation in daily cycles because the bats engage in diurnal sleep and nocturnal activity.
In my last blog on E.6a, I described the social organization of honey bees. The syllabus requires us to describe one other non-human example, which is what this blog will mainly be about.
Social organisms live together and work together to maximize the population’s chances of survival (which would equate to maximum reproduction and passing on alleles to subsequent generations); natural selection thus selects for colonies as a whole instead of individuals.
- Conditioned stimuli: stimuli which produce responses with learning–these responses are conditioned
- Unconditioned stimuli: stimuli which produce responses without learning being necessary–these responses are unconditioned
- Innate behavior: Genetically programmed animal behavior–develop independently of environment
- Learned behavior: Behavior that develops as a result of an animal’s experiences
On Tuesday, we’ll be starting our eighteenth and final unit: behavior.
- Behavior: the pattern of responses in an animal
- Neurobiology: study of the nervous system of animals
- Receptors: detect stimuli; can be sensory cells or nerve endings of sensory cells
- Reflex: a rapid unconscious response to a stimulus
- Response: a change in an organism, produced by a stimulus
- Stimulus: a change in the environment, either internal or external, that is detected by a receptor and elicits a response
In my last blog post, I mentioned cocaine and tetrahydrocannabinol (THC), and in this one I’ll be describing their effect in more detail.
Before that, I’ll outline the ways that psychoactive (affecting the mind) drugs can affect synaptic transmission.
- We’ve learned about inhibitors in the past, and psychoactive drugs can act as inhibitors to neurotransmitters with a similar chemical structure. By binding to the receptor for those neurotransmitters, the drugs inhibit the NTs from binding and thus prevent the effect as well.
- Some psychoactive drugs may cause similar effects as NTs that have similar chemical structures; however, drugs are not broken down and cause an effect for a greater duration of time.
- Not only can drugs interfere with the binding of the NTs, but they can also interfere with the breakdown/reabsorption, causing an effect for a greater duration of time (similar to #2).
- Excitatory neurotransmitters: neurotransmitters that stimulate action potentials in the post-synaptic neuron
- Psychoactive drugs: drugs that affect the brain and personality by altering the functioning of synapses
- Summation: additive effect from multiple releases of neurotransmitter
I already blogged about the pages for today, so instead of a summary I’ll be discussing an article about an issue discussed in this section: animal experimentation.
There was an article on cyborg rat tests in 2012. The scientists at Israel’s Tel Aviv University replaced damaged brain tissue with microchips that are stimulated by electrodes. Using the microchip, the rat is able to produce responses that require the damaged part of the brain. This research aims to help those with neurodegenerative diseases or those who have experienced brain strokes, and the scientists will continue with human subjects after finishing animal trials.
Although animals have been used extensively in research, there have been moves to decrease reliance on animals.
Professor Denis Noble and his team created the first virtual heart, which can “replace some of the very early stages in animal experimentation.”
In 2006, Dr. Phil Stephens had been developing an in vitro system to aid in his research on chronic leg and diabetic foot ulcers in the aged, which will “enable a vast number of pre-screens to be undertaken, hopefully vastly reducing the number of animal experiments that go on.”
Professor Chris Higgins uses MRI to investigate the genetic and environmental factors that cause obesity, and imaging has allowed him to decrease the number of animals he uses for a single experiment from hundreds to around six.
- Free nerve endings: perceive mechanical, thermal or chemical stimuli
- Peripheral nervous system: nerves outside the CNS
- Voluntary nervous system: has motor and sensory neurons
- Autonomic nervous system: controls unconscious processes and consists of the parasympathetic and sympathetic nervous systems.