Chapter 4 Flashcards
How does new variations are introduced besides the merging of the DNA of your parents?
Mutations, recombinations, and microduplications of genes
choosing individuals with desired trait and make them the parents of the next generation -> humans (breeders)
You can influence evolution by using or failing to use your body parts (wrong theory)
Does “evolution” mean “improvement”?
no, just that the fittest survive. Evolution is not goal directed. Some traits are from situation to situation more or less useful. Maybe they were useful in the past, maybe they will be useful in the future.
Does evolution benefit the individual or the species?
Neither: It benefits the genes! In a sense, you don’t use your genes to reproduce yourself. Rather, your genes use you to reproduce themselves
Many people believe the human appendix is useless.
Will it become smaller and smaller with each
No. Failure to need a structure does not make
it smaller in the next generation. The appendix will
shrink only if people with a gene for a smaller appendix
reproduce more successfully than other people do.
concerns how behaviors evolved. The emphasis is on evolutionary and functional explanations
the idea that individuals help those who will return the favor. The idea is not just “you scratched my back, so I’ll scratch yours,” but also “you scratched someone else’s back, so I’ll scratch yours.” By helping others, you build a reputation for helpfulness
controversial hypothesis for altruism: group selection
altruistic groups thrive better than less cooperative ones. True, but: wouldn’t an uncooperative individual within the cooperative group gain an advantage?
What are plausible ways for possible altruistic genes to spread in a population?
Altruistic genes could spread because they
facilitate care for one’s kin or because they facilitate
exchanges of favors with others (reciprocal altruism).
Group selection may also work under some circum-
stances, especially if the cooperative group has some
way to punish or expel an uncooperative individual.
what does a developing baby does first: sensing or moving?
is the production of new cells.
the five different processes in the development of neurons:
proliferation, migration, differentiation,
myelination, and synaptogenesis
Where and what are stem cells?
Everywhere, they divide and send the copy (or themselves, does not matter) where it is needed to differentiate there
the cells begin to move on particular positions
Changing into another cell (e.g. an axon or a dendrite)
“While migrating, a cell can already differentiate into an axon.” True or false?
True, it can either migrate with its tip still migrating or pushing its tail towards its destination
“While migrating, a cell can already develop its dendrites.” True or false?
False, it can already differentiate into an axon, but the dendrites develop when migration ends.
what is myelination and where does it start?
the process by which glia produce the insulating fatty sheaths that accelerate transmission in many vertebrate axons. Starting in the spinal cord, then hindbrain, midbrain, and finally forebrain
the formation of synapses.
Which develops first, a neuron’s axon or its dendrites?
The axon forms first.
How to test how old your cells are?
Checking the Carbon level. (^14)C corresponds to a certain year, e.g. skin is 1 year old, bones are 15 years old cells
New receptor neurons form in adult rodents for which
What evidence indicated that new neurons seldom
or never form in the human cerebral cortex and
The (^14)C concentration in the DNA
of human neurons in the cerebral cortex and olfactory
bulbs corresponds to the level during the year the per-
son was born, indicating that all or nearly all of those
neurons are as old as the person is.
Paul Weiss & Roger Sperry
Weiss thought axons of detached limbs connect at the place they are and “tune” afterwards so that they send the right information to the brain.
Sperry showed in newt’s that axons, while connecting are attracted by some and repelled by other chemicals and therefore connect just to specific axons
What was Sperry’s evidence that axons grow to a
specific target instead of attaching at random?
If he cut a newt’s eye and inverted it, axons grew
back to their original targets, even though the con-
nections were inappropriate to their new positions on
How does axons find the right location to bond and connect functional?
the chemical gradients steer them approximately (not accurately) to the right location, there the axons forms synapses onto different axons and receives synapses from many. The post synapse strengthens the most appropriate and eliminates others
In the development of
the nervous system, we start with more neurons and synapses
than we can keep. Synapses form with approximate accuracy,
and then a selection process keeps some and rejects others.
The most successful axons and combinations survive, and
the others fail.