Biology unit 4

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  • Created by: Lauren
  • Created on: 06-06-14 17:52
What is a population?
A group of interbreeding organisms of the one species in a habitat
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What is a Community?
All the populations of different species living and interacting in a particular place at the same time.
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What is a habitat?
Where a community of organisms live.
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What is a niche?
Where an organism lives, and what it does there, this includes biotic and abiotic features required for survival
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Define: (1) Biotic (2) Abiotic
(1) Living (2) Non-Living
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What is an adaptation?
A feature that members of a species has that increases chance of survival and reproduction
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What is Ecology?
They study of the inter relationships between organisms and their environment
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What is the biosphere?
The life supporting layer of air, land and sea that surrounds the earth.
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What is an ecosystem?
Is made up of all the interacting biotic and abiotic features in a specific area
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Name 2 Biotic interactions.
1. What the organism eats (Prey) 2. What the organism is eaten by (predication)
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Name 4 Abiotic interactions.
Temperature, Humidity, Light, PH, Oxygen concentration
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Factors to consider when using a quadrate (3)
1. Size of quadrat // 2.Number of quadrats // 3. Position of quadrat (Overall more quadrat's = More reliable results)
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Random sampling method
1. Avoids bias - Lay out two long measuring tapes at right angles, along to sides of the study area. Obtain a series of coordinates using random no. generated by a computer. Place the quadrat at the intersection of the pair of coordinates & record
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To obtain reliable sample results... (3)
1. Large sample size - more representative of community as a whole 2. Calculate a mean of samples 3. Many quadrats used
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Advantage and disadvantage of frequency measurements
Adv . Gives a brief idea of distribution and what species are present. Disad. Doesn't provide info on density or detailed distribution
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Advantage and disadvantage of percentage cover
Adv. Useful when the species is abundant and difficult to count. Also quicker that counting individual plants. Disad. Less helpful when organisms occur in overlapping layers
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Mark - release - recapture method (Investigates mobile populations)
A known number of individuals are caught and marked in some way. They are them released back into community and given sufficient time to distribute themselves evenly among population. After a given no. of individuals r collected randomly. Marked reco
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Calculation to estimate population size
no. in sample 1 X no. in sample 2 / no. marked recaptured.
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What will the effect on the final population size be, if the mark made individuals more liable to preditation
The population will appear larger. Because there will be proportionally fewer marked individuals in the 2nd sample
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Other cards in this set

Card 2


What is a Community?


All the populations of different species living and interacting in a particular place at the same time.

Card 3


What is a habitat?


Preview of the front of card 3

Card 4


What is a niche?


Preview of the front of card 4

Card 5


Define: (1) Biotic (2) Abiotic


Preview of the front of card 5
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