E.6d Food, Sleep, Sex

03/03/2014 § 2 Comments

If you’d look at the title, you’ll see the one thing I want more than anything in the world but can never get because I’m a lonely loser: SSSSSSSSSSSSLEEP. (gotcha)

 

Foraging is the search/hunt for food amongst animals. Different animals take into account different factors when they forage, for example the bluegill sunfish classifies their prey into small, medium, and larger sizes. If the target is small (of low density), then it would eat a lot of that size, if only to gain enough energy/food. If the target is of high density, it would select a larger size, to get the most energy through one individual. If the prey is of medium density, it would choose large prey over small prey.

Another word for us is courtship, which is a complex interplay of two sets of communications. Courtship is how potential mates inform each other and read each other’s signals to know whether or not they’ll mate. Courting stimuli is normally specific to a species, allowing individuals to breed only within its own species. Factors that therefore affect courtship include: health, size, aggressiveness, resources, adaptive abilities, and parental investment.

Hey, that sounds like human.

 

DBQ page 355:

1) The flight lengths are shorter in autumn, measuring between 1-2 hours. Before sunrise, there is little to no activity and most flights happen before sunset. All flights end by 2100.

2)

  • a) During the summer there are many flights per day compared to during the autumn, when there is only one flight per day. However in both summer and autumn, all flights seem to start after sunset and end before sunrise.
  • b) There might be a difference in behaviour because the environment changes with the season, making foraging harder during the autumn, which is why more flights happen during the summer and less happen during the autumn simply because there isn’t enough food. Also, summer could be mating season, huehuehue.

3) The bats are an example of rhythmical variation because they are nocturnal, meaning they forage at night and sleep in the mornings (aka my life). That’s daily; annually, more activity happens during the summer compared to in the autumn, when things calm down for the bats and they only fly once a day.

E.6b Reciprocal Altruism

03/03/2014 § Leave a comment

Now, if the whole world could be reciprocally altruistic, then we’d have a lot less problems, wouldn’t we.

 

As its name suggests, reciprocal altruism is a type of altruism. (Wow.) Simply put, this type of behaviour, again, benefits mostly the recipient and comes at a cost to the donor. The difference between reciprocal altruism and kin selection is that the former happens between non-relative individuals. Like friends among human beings. Strange creatures, those humans.

The best example of reciprocal altruism can be seen in vampire bats, ofmgkfgk, they are so cute. Female vampire bats (I have no idea what happened to the male vampire bats but there were none in the videos) have to eat constantly due to their high metabolism and high surface area to volume ratio. If they don’t eat for more than 2½ days, then they’re going back in the coffin.

(ha ha)

So what happens is that each female vampire bat has a best friend (like you and me) who, if they weren’t able to forage anything for the night, will willingly regurgitate some of their own food so they can survive long enough to find food the next night. In response to this, if that friend needs help later, the original female vampire bat should also reciprocate and also give the friend food. Sometimes they don’t but those cheats are caught and banished faster than they can say “Dracula.”

E.6c Kin Selection

01/03/2014 § Leave a comment

If you wanted to be in the hall of fame, why can’t you just say so?

(LOOOOOOOOL I’M JOOOOKING.)

 

Well, okay, let’s see. What is kin selection. Kin selection is a type of altruistic behaviour found in few species, not including humans. Humans are very into kin selection, if you don’t mind my informality. The downside of kin selection is that you don’t get to pass on as many of your genes into the next generation, but by choosing to support at least members of the species that you share genes with, at least some of your genes (the ones shared by that kin) will be passed on to the next generation. Altruistic behaviour is (sort of silly) disadvantageous to the performer because it’s costly to them but benefits the recipient. “Survivor of the fittest” plays little to no role in altruism and kin selection.

One example of kin selection can be found in the silver-backed jackal (but on the projector they look yellow). Instead of leaving to start its own pack (family), a young male (or female? Actually I’m not sure) would stay to help its parents with their family and increase their chances of survival. The yearling won’t be able to see as much of its genes in the next generation as it would if it started its own family but at the same time, there’s no guarantee that an inexperienced yearling would even be able to start its own family. (Costs and benefits, yo.) Clearly altruism has more disadvantages to the donor than advantages, so it’s silly right? Right.

E.3b Learned Behavior

23/02/2014 § Leave a comment

one day i’ll be a good student
that day is not today

 

Didn’t I define “learned behaviour” last time?

 

DBQ page 238:

1. The first sonogram’s frequency is more stable and flat compared to the second sonogram. In the second sonogram, there is a long period of heavily fluctuating frequency compared to the short period of heavy fluctuation in the first sonogram towards the end of its song.

2.

  • a) The third sonogram’s pitch fluctuates less than the first two sonograms. The amplitude of the third sonogram is much thicker, meaning that the third song is louder than the other two songs.
  • b) The song is both innate and learned. All of the white-bird sparrow populations will sing the same, if not a similar pattern as their song, which makes the song innate in the species. At the same time, there were some songs that were different, namely in the third sonogram with a different environment.

3.

  • a) Sonogram V holds similarities to the beginning portions of the first three sonograms. Sonogram V’s pitch fluctuations are more similar to those of sonogram IV, particularly in how they both slope downwards. By contrast, sonogram V has higher fluctuations than sonogram IV.
  • b) The initial section of sonogram V is similar to the initial sections of sonogram I and II, where the song flatlines at a single pitch.
  • c) Birds would normally stick to their own birdsong to stay safe within their own species. Unless they need to attract other species, which they don’t, birds use their songs to attract potential mates from their own species. They don’t sing other songs for fear of attracting competition and predators.
  • d) These observations are evidence of learned development in birdsongs. Species are able to put aside its innate behaviour and learn something new based on environmental influences.

E.3a Innate Behavior

20/02/2014 § Leave a comment

If humans can identify each other and gorillas could identify each other, then would humans be to gorillas as gorillas are to humans? Discuss.

 

Words first, words words words. Innate behaviour is behaviour shown in all normal members of a species despite any variation in the environment. By contrast, learned behaviour is an alteration or modification of behaviour that is the result of experience.

 

DBQ page 326:

1. Another method to encourage the woodlice to move into one of the arms is to place food in one of the arms, which is a form of chemotaxis.

2. The data shows that most of the woodlice are attracted to the scented arm than to the unscented arm. Only a little over 30% moved into the unscented arm.

3. For the woodlice to receive smell and respond to it, they must have chemoreceptors that can react to the chemicals released by the smells.

4.

  • a) Woodlice would move to the scented arm because they know there are members of their own species there, and for survival and reproduction, that would mean that there are potential mates in that arm compared to the unscented arm. This means that woodlice might use scent for mating (to signal to each other their locations).
  • b) Woodlice might move to the unscented arm to avoid competition and to survive by itself without reproduction. If large populations of the species tend to overpopulate, some woodlice may have learned to avoid their own species for a better chance of survival.

E.1 Reflexes

18/02/2014 § Leave a comment

 

Can you believe this is the last unit, cause I sure can.

 

In E.1 we have a few words (okay, a lot of words) to remember but three important ones are stimulusresponse, and reflex. The definition of stimulus is easy enough to remember if you remember your alphabet, specifically CDE. A stimulus is a Change in the internal/external environment that is Detected by a receptor and Elicits a response. EASY (I wish). A response is produced by a stimulus and produces a change in the organism. A reflex is a rapid, unconscious response to a stimulus. The elements of responses of animals to stimuli include not only receptors but all types of neurons (namely sensory neurons, relay neurons, and motor neurons), synapses, and effectors.

We also need to draw and label a diagram on the reflex arc for pain including the following elements (as well as most everything listed above):

  • sensory pain signals enter dorsal root of spinal cord
  • interneurons in spinal cord stimulate flexor motor neurons
  • interneurons inhibit extensor motor neurons
  • motor neurons exit spinal cord & stimulate flexor muscles
  • extensor muscles relax
  • withdrawal of leg
  • neurotransmitter = acetylcholine
  • bisynaptic reflex

E.4c Neurotransmitters & Drugs

27/01/2014 § Leave a comment

Yooooooooooo, kids, don’t do drugs.

x

Well, first of all, what kind of drugs are we talking about. The syllabus told me that we’re looking at THC and cocaine (thank you, syllabus).

THC is an inhibitory psychoactive drug that decreases synaptic transmission. THC binds to cannabinoid receptors, which results in the inhibition of the release of neurotransmitters from pre-synaptic neurons. If these neurons are reduced in concentration (for example, the neurotransmitter GABA), the result is an increase in dopamine release. Essentially, THC affects the cerebellum (motor functions), hippocampus (memory), and the cerebral cortex (higher level thinking).

Cocaine is an excitatory psychoactive drug that increases synaptic transmission. It binds to membrane proteins that pump dopamine into pre-synaptic neurons and causes an increase of dopamine. So cocaine technically causes euphoria, seeing as dopaminergic synapses are associated with pleasure. Of course, cocaine is also addictive, so the brain adjust and adapts to a regular consumption of dopamine by reducing dopamine receptors. This causes depression when an individual experiences cocaine withdrawal (or any drug withdrawal). Examples of cocaine? CRACK. The causes of this addiction include genetic predisposition, social factors, and dopamine secretion. That will be for later. For now, kids, don’t do drugs. Don’t even think about it.

Where Am I?

You are currently browsing the HL2 Biology category at i am so.