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# BIOL4 Biology Unit 4 Exam - 13th June 2011 watch

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1. Whats the difference between transects and quadrats and when do you use each one of them?
2. (Original post by Jing_jing)
They're pretty much the same thing, just the wording is different

Basically Net=Gross - Respiratory losses

(Original post by Rickesh)
net productivity= the amount of energy left after respiration
gross productivity is the rate at which plants assimilate the chemical energy
also the net productivity is the amount of energy available for the next trophic level
3. (Original post by Black Butler)
also the net productivity is the amount of energy available for the next trophic level
And indications potential crop yields in agricultural ecosystems.
4. Whats the difference between transects and quadrats and when do you use each one of them?
Transects are when your investigating something over a gradient such as succession. What you do is use quadrats but over set intervals using systematic sampling. Quadrats are used just to indicate abundance of a species or its spread.
5. (Original post by FatalError)
Transects are when your investigating something over a gradient such as succession. What you do is use quadrats but over set intervals using systematic sampling. Quadrats are used just to indicate abundance of a species or its spread.
6. (Original post by FatalError)
Transects are when your investigating something over a gradient such as succession. What you do is use quadrats but over set intervals using systematic sampling. Quadrats are used just to indicate abundance of a species or its spread.

(Original post by Rickesh)
Whats the difference between transects and quadrats and when do you use each one of them?
Transects also ensure each community is sampled which maynot be true with random sampling. yeeaah
7. What is the difference between Lactate and Lactic acid?
8. (Original post by Black Butler)
Transects also ensure each community is sampled which maynot be true with random sampling. yeeaah
therefore increasing the reliability :P
9. Oh yeah when do you use abundance frequency and abundace percentage cover for sampling and what are the advatages/disadvantages for each

and what are they (each of them?)
10. (Original post by FatalError)
What is the difference between Lactate and Lactic acid?
urmm I have no idea...gonna take a guess and say lactate is produced in anaerobic conditions and lactic acid is.....? psshht i dont know ?
11. urmm I have no idea...gonna take a guess and say lactate is produced in anaerobic conditions and lactic acid is.....? psshht i dont know ?
It's the same thing. Anything with 'ate' is an acid.
12. (Original post by Black Butler)
Oh yeah when do you use abundance frequency and abundace percentage cover for sampling and what are the advatages/disadvantages for each

and what are they (each of them?)
Abundance frequency is used when y ou have a large sample??
Advantages: quick, easy, gives a general idea of number of species present, but it doesnt give enough detail and can be biased.
Percentage cover is where you give an estimate of the % in your quadrat,
Advantages: quick, do not need to count

That was rubbish lol whats the answer?
13. (Original post by Black Butler)
Oh yeah when do you use abundance frequency and abundace percentage cover for sampling and what are the advatages/disadvantages for each

and what are they (each of them?)
you use percentage cover when wanting to, well find the percentage cover of a species over a particular area. and same for frequency, you do that when you want to find out the number of organisms of a species in a particular area.

the advantage of abundance percentage cover is that you don't need to distinguish between overlapping plants of the same species.

advantage of abundance frequency is that it is a quick method, easy, reliable if a large enough sample size is used. ???
14. (Original post by Rickesh)
Abundance frequency is used when y ou have a large sample??
Advantages: quick, easy, gives a general idea of number of species present, but it doesnt give enough detail and can be biased.
Percentage cover is where you give an estimate of the % in your quadrat,
Advantages: quick, do not need to count

That was rubbish lol whats the answer?
Dont know bro -thats why i asked the question. Ive got the text book in front of me but y mind is blank.
15. Abundance is just the number of individuals particular species in a given area. Using frequency is the likelihood of the species being present in the quadrat e.g. it may be present in 24/100 quadrats. It's useful when individuals are hard to decipher.

Disadvantages being that there's no indication of species density.

Percentage cover is the percentage of a quadrat it covers (say 46%). The advantage being that invidivual species do not have to be counted and information gained rapidly.

Disadvantages when some species such as grass overlap so it can be subjective.
16. (Original post by FatalError)
Abundance is just the number of individuals particular species in a given area. Using frequency is the likelihood of the species being present in the quadrat e.g. it may be present in 24/100 quadrats. It's useful when individuals are hard to decipher.

Disadvantages being that there's no indication of species density.

Percentage cover is the percentage of a quadrat it covers (say 46%). The advantage being that invidivual species do not have to be counted and information gained rapidly.

Disadvantages when some species such as grass overlap so it can be subjective.
Could you explain the bolded part please
17. Hey guys, good luck for the exam tomorrow!!

Just a small favour, could someone please explain to me about conservation and succession

thanks!!
18. Can someone help me with a question on the Jan 08 paper? It doesn't say here which question but it's a question about Cheetahs, and it's part (iii) of the question.

How do you know that the King Cheetahs are homozygous recessive? (q2)? And not homozygous dominant? Thanks.
19. Describe and explain : integrated post-control system

5 marks
20. (Original post by Black Butler)
Could you explain the bolded part please
When assessing percentage cover you make an estimate of the area covered by a species. However if there are different layers of plants, such as grass and taller plants or shrubs then you may end up missing some plants as they are covered and so your method is only an estimate and not precise.

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