Piddly
Badges: 11
Rep:
?
#1
Report Thread starter 8 years ago
#1
I asked my biology teacher and he said that the textbook was right, but he's an idiot and I'm not convinced... so I'm asking you guys

In captor 9.1 - Sensory Reception, the textbook says "An example of a kinesis occurs in woodlice. [...] When they are in a dry area they move more rapidly and change direction more often. This increases their chance of moving into a different area.

However this doesn't make any sense to me. Surely if woodlice wanted to find a new area, they should change direction less often. When they find a favourable area, they should then change direction more often, keeping them in the same place.

Help?
1
reply
Eloades11
  • Study Helper
Badges: 17
Rep:
?
#2
Report 8 years ago
#2
(Original post by Piddly)
I asked my biology teacher and he said that the textbook was right, but he's an idiot and I'm not convinced... so I'm asking you guys

In captor 9.1 - Sensory Reception, the textbook says "An example of a kinesis occurs in woodlice. [...] When they are in a dry area they move more rapidly and change direction more often. This increases their chance of moving into a different area.

However this doesn't make any sense to me. Surely if woodlice wanted to find a new area, they should change direction less often. When they find a favourable area, they should then change direction more often, keeping them in the same place.

Help?
This is definitely a mistake, when in favourable conditions a kinesis would be that the organism slows down movement and changes direction more.

When is unfavourable conditions, the organism will speed up and change direction LESS
2
reply
Piddly
Badges: 11
Rep:
?
#3
Report Thread starter 8 years ago
#3
(Original post by Eloades11)
This is definitely a mistake, when in favourable conditions a kinesis would be that the organism slows down movement and changes direction more.

When is unfavourable conditions, the organism will speed up and change direction LESS
Thanks for clearing that up for me
1
reply
janet9
Badges: 13
Rep:
?
#4
Report 8 years ago
#4
It is a mistake, yes! Even the CGP book has a little mistake too in the Kinesis area. My teachers honestly detest the NT book - they made contracts to publish editions before a certain date, but got a bit late so most likely rushed it a bit - but some parts are brilliant, such as the homeostasis diagrams. The best books ever = Your notes + nuggets from the NT book + pearls from the CGP revision guide, but ultimate preparation lies in practicing past papers, and practicing some more! Good luck to all!
0
reply
Radekal
Badges: 8
Rep:
?
#5
Report 8 years ago
#5
Guys.. the OCR textbook says that "if placed in dry/bright conditions woodlice will move around rapidly and randomly" Doesn't that imply an increased rate of turning as well?
0
reply
Eloades11
  • Study Helper
Badges: 17
Rep:
?
#6
Report 8 years ago
#6
(Original post by Radekal)
Guys.. the OCR textbook says that "if placed in dry/bright conditions woodlice will move around rapidly and randomly" Doesn't that imply an increased rate of turning as well?
Woodlice prefer dark damp conditions, so in the case that they're in dry/bright conditions, they will speed up and change direction less. However I agree with what you said, but the book says they move randomly, which is true. But the book has made no reference to whether or not the woodlice change direction more or less
0
reply
Alison1992
Badges: 13
Rep:
?
#7
Report 8 years ago
#7
(Original post by Piddly)
I asked my biology teacher and he said that the textbook was right, but he's an idiot and I'm not convinced... so I'm asking you guys

In captor 9.1 - Sensory Reception, the textbook says "An example of a kinesis occurs in woodlice. [...] When they are in a dry area they move more rapidly and change direction more often. This increases their chance of moving into a different area.

However this doesn't make any sense to me. Surely if woodlice wanted to find a new area, they should change direction less often. When they find a favourable area, they should then change direction more often, keeping them in the same place.

Help?
woodlice do not like to be dry, they are moving more rapidly to find the favourable moist area more quickly, such is kinesis
0
reply
Piddly
Badges: 11
Rep:
?
#8
Report Thread starter 8 years ago
#8
(Original post by Alison1992)
woodlice do not like to be dry, they are moving more rapidly to find the favourable moist area more quickly, such is kinesis


I know I completely understand the part about moving more rapidly, notice it is the part about the changing direction more often that I put in bold font.

If you were to change direction more often you would be more likely to stay in the same place. In order to find pastures new, the woodlice should walk rapidly in a straight line, surely?
0
reply
Alison1992
Badges: 13
Rep:
?
#9
Report 8 years ago
#9
(Original post by Piddly)
I know I completely understand the part about moving more rapidly, notice it is the part about the changing direction more often that I put in bold font.

If you were to change direction more often you would be more likely to stay in the same place. In order to find pastures new, the woodlice should walk rapidly in a straight line, surely?
erm no, that would be a taxes
1
reply
Eloades11
  • Study Helper
Badges: 17
Rep:
?
#10
Report 8 years ago
#10
(Original post by Piddly)
I know I completely understand the part about moving more rapidly, notice it is the part about the changing direction more often that I put in bold font.

If you were to change direction more often you would be more likely to stay in the same place. In order to find pastures new, the woodlice should walk rapidly in a straight line, surely?
Remember a kinesis is not a directional movement towards or away from a stimulus, a kinesis where the organism is in unfavourable conditions means it will speed up and change directions less, not completely change the direction. The woodlice needs to find damp conditions, it can't just walk in a straight line, what if it hits a rock? Climb over it into more light/dry conditions, not good

(Original post by Alison1992)
erm no, that would be a taxes
He didn't specify which direction, so if it was directly towards or away from the stimulus, then yes it's a taxis, but if it was in any other direction, it usually tends to be a kinesis
0
reply
tasha_atl
Badges: 3
Rep:
?
#11
Report 8 years ago
#11
No it's not a mistake, as said before moving towards a new area would be taxis not kinesis. If they are moving quickly and changing direction often they are more likely to find a favourable enviroment and when they do their rate of movement is reduced to stay in the enviroment. That's what I learnt for the exam last year
0
reply
Eloades11
  • Study Helper
Badges: 17
Rep:
?
#12
Report 8 years ago
#12
(Original post by tasha_atl)
No it's not a mistake, as said before moving towards a new area would be taxis not kinesis. If they are moving quickly and changing direction often they are more likely to find a favourable enviroment and when they do their rate of movement is reduced to stay in the enviroment. That's what I learnt for the exam last year
It is a mistake, if you change direction more often, you are likely to stay in the same place eg. running around in a circle, will keep you in roughly the same favourable conditions. The book states that when in unfavourable conditions, you change directions more, in order to stay in the same place, now that wouldn't be very suitable if you wanted to get out of the unfavourable conditions would it? :rolleyes:
0
reply
tasha_atl
Badges: 3
Rep:
?
#13
Report 8 years ago
#13
(Original post by Eloades11)
It is a mistake, if you change direction more often, you are likely to stay in the same place eg. running around in a circle, will keep you in roughly the same favourable conditions. The book states that when in unfavourable conditions, you change directions more, in order to stay in the same place, now that wouldn't be very suitable if you wanted to get out of the unfavourable conditions would it? :rolleyes:
Ahh yes, they do change direction less often. My mistake.

It isn't directional in the sense that the woodlouse see a nice dark and humid place and runs towards it, nor is it directional away from the stimulus. That's what I meant Maybe trying to remember biology isn't such a good idea :/
0
reply
Piddly
Badges: 11
Rep:
?
#14
Report Thread starter 8 years ago
#14
(Original post by Eloades11)
Remember a kinesis is not a directional movement towards or away from a stimulus, a kinesis where the organism is in unfavourable conditions means it will speed up and change directions less, not completely change the direction. The woodlice needs to find damp conditions, it can't just walk in a straight line, what if it hits a rock? Climb over it into more light/dry conditions, not good
Well yes I don't mean that the woodlice to stick to the straight line religiously, should have just wrote change direction less I guess.

But you agree that the text book has got it slightly wrong?
0
reply
Abby :)
Badges: 8
Rep:
?
#15
Report 8 years ago
#15
I thought it was right... because changing direction more times makes you more likely to find somewhere NEW quicker, with more favourable conditions?

Oh im confused. -.-
1
reply
Eloades11
  • Study Helper
Badges: 17
Rep:
?
#16
Report 8 years ago
#16
(Original post by Piddly)
Well yes I don't mean that the woodlice to stick to the straight line religiously, should have just wrote change direction less I guess.

But you agree that the text book has got it slightly wrong?
I wouldn't say they got it wrong, but the book should have compared the favourable conditions and the unfavourable ones, which I'm sure it has done, it wouldn't be a lot of help if it hasn't

EDIT: Then I was referring to the OCR textbook, the AQA nelson thornes one is completely wrong

(Original post by Abby :))
I thought it was right... because changing direction more times makes you more likely to find somewhere NEW quicker, with more favourable conditions?

Oh im confused. -.-
Take a look at the drawings I've attached, all the lines are the same length(theoretically, I haven't measured them), the line on the top is where the direction has been changed more, so it stays closer together, the line in the middle is where a woodlice has changed directions less, and is moving out of unfavourable conditions. The line on the bottom represents a woodlice in favourable conditions, so it has changed directions more to stay in these conditions. See how it has barely moves from where it has started?
Attached files
0
reply
Abby :)
Badges: 8
Rep:
?
#17
Report 8 years ago
#17
(Original post by Eloades11)

Take a look at the drawings I've attached, all the lines are the same length(theoretically, I haven't measured them), the line on the top is where the direction has been changed more, so it stays closer together, the line in the middle is where a woodlice has changed directions less, and is moving out of unfavourable conditions. The line on the bottom represents a woodlice in favourable conditions, so it has changed directions more to stay in these conditions. See how it has barely moves from where it has started?
Aaaah i get it, thanks alot!<3
0
reply
Seasick Steve
Badges: 12
Rep:
?
#18
Report 8 years ago
#18
Yeah, my teahcer pointed that out as a mistake
0
reply
fjordgirl75
Badges: 0
Rep:
?
#19
Report 8 years ago
#19
The book is correct. Woodlice turn correct, that is if they make a right turn, they will subsequently make a left turn. At speed this will ensure they explore the maximum amount of territory/habitat and this find favourable conditions. Walking in a straight line would limit the number of new environments they encounter.

My dissertation was on this very topic. If woodlice are in an adverse environment they will exhibit a kinesis response at speed and this will be in a zig zag motion or similar. They will not move in a circle due to their turn correction response which is activated by an obstacle (they will then make an oposite turn) or muscle fatigue.

The book is correct, sadly it appears there are many teachers who do not have the in depth knowledge on this subject.

Woodlice will also slow the response when the favourable environment is found. That is wet/damp and dark.
0
reply
POWCATTY
Badges: 11
Rep:
?
#20
Report 8 years ago
#20
i always understood it to mean that by moving faster and changing directions more often you will reach favourable conditions faster. when in favourable conditions you move slower and change direction less because you dont need to go anywhere.
if you are in unfavourable conditions and you dont change direction you will head in a straight line, but by zigzaging you are covering the most ground and therefore increase your chances of finding better conditions.
there are mistakes in the books, but im sure this is not one of them.
1
reply
X

Quick Reply

Attached files
Write a reply...
Reply
new posts
Back
to top
Latest
My Feed

See more of what you like on
The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

Personalise

University open days

  • The University of Law
    Solicitor Series: Assessing Trainee Skills – LPC, GDL and MA Law - Guildford campus Postgraduate
    Wed, 29 Jan '20
  • Nottingham Trent University
    Postgraduate Open Day Postgraduate
    Wed, 29 Jan '20
  • University of Groningen
    Undergraduate Open Day Undergraduate
    Fri, 31 Jan '20

Have you ever signed up for an open day and then not gone to it?

Yes (148)
52.11%
No (136)
47.89%

Watched Threads

View All