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Biology > Population ecology > Flashcards

Population ecology Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

What is population size?

A

the number of individuals

larger populations = larger variety = more potential for adaptation

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2
Q

What is population density?

A

the number of individuals per unit geographic area

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3
Q

What are population density limiting factors?

A

limitations to population growth

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4
Q

What are the 2 types of population density limiting factors?

A

density-dependent

density-independent

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5
Q

What are density-dependent population density limiting factor?

A

disease OR Predators

competition Availability of resources

predation Nutrient supply

food Disease

nesting sites Accumulation of wastes

mates

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6
Q

What are density-independent population density limiting factors?

A

often abiotic OR Phenomena

sunlight Abiotic factors

temperature Weather conditions

reainfall

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7
Q

What are terms to describe population distribution?

A

Random

Clumped

Uniform

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8
Q

What is the difference btw natality and mortality?

A

natality -
increase population size as offspring are added to the population

mortality -
decreases the population size as some individuals get eaten, die of age, get sick

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9
Q

What is the difference btw immigration and emigration?

A

immigration -
increases population size as individuals have moved into the area from somewhere else

emigration -
decreases the population size as individuals have moved out of the area

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10
Q

What is the population size formula (general)?

A

Pop. size = (Immigration + Natality) - (Mortality + Emigration)

Mnemonic:
Pee IN ME

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11
Q

What are the phases of the sigmoid population growth curve?

A
  1. Exponential
  2. Traditional
  3. Plateau
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12
Q

What occurs during the exponential phase of the sigmoid curve?

A

rapid increase of population

natality > mortality

Resources = ABUNDANT

Diseases + predators = RARE

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13
Q

What occurs during the traditional phase of the sigmoid curve?

A 
natality = DECREASE
mortality = INCREASE

Resources = DECREASE

Pop. = increase but at SLOWER RATE

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14
Q

What occurs at the plateau phase of the sigmoid curve?

A

No more population growth = constant population size

natality = mortality

pop. reached CARRYING CAPACITY of environment

resources = limited

Predators + disease = common

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15
Q

What is carrying capacity?

A

is the MAXIMUM a population size that can be supported by the environment

e.g. if pop. is limited by resource shortage = carrying capacity

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16
Q

What are r reproductive strategies?

A

small resource investment
= low effort babes

nop protection
= increase mortality %

egg fertilised THEN dispersed

More common for animals wt shorter lifespan

17
Q

What are k reproductive methods?

A

relates to carrying capacity (competitive world)

heavy investment (i.e protection + parenting)
   = increase survival %

common in larger animals + animals that are long lived wt longer period of maturation + adulthood

18
Q

How can you measure a population size?

A

Immigration + Natality + Emigration + Mortality + limiting factors
= IMPRACTICAL TO COUNT POP. OVER LARGER AREA

therefore: SAMPLING e.g.

sampling -
identifying individual #s in small areas (RANDOM + UNBIAS) then estimating totals

quadrats -
for non-mobile / sessile species

19
Q

How does the capture-mark-release-recapture sampling method used?

A

area defined & marked off

selection of individuals captured, counted, marked, released (n1)

after time (n1 reintegrated) second capture made (n2)
all animals (marked & not marked) counted (n3)

related to Lincoln Index

20
Q

What is the Lincoln Index?

A

pop. size = (n1 x n2) / n3

n1 = # in 1st capture
n2 = # collected in 2nd capture
n3 = # marked in 2nd capture
21
Q

What are the assumptions associated wt the Lincoln Index?

A
  1. ALL INDIVIDUALS EQUAL CAPTURE %
  2. MARKED individuals RANDOMLY DISTRIBUTED after release (n1 CANNOT AFFECT n3)
  3. MARKING will NOT AFFECT natality + mortality
22
Q

How can Lincoln Index accuracy be improved?

A

Increase capture sample size

take REPEATED samples

23
Q

What are quadrats?

A

a square wt a known frame

placed randomly then count # of species/ coverage %
REPEAT

observe presence / absence of species
therefore, # quadrats wt both species compared to total # quadrats

24
Q

What are the quadrat formulas?

A

pop. size = (mean # per quadrat x total area) / area of each quadrat

estimated average density = total # individuals counted / (# quadrats x area of quadrat)

25
Q

What is the purpose of the chi square test?

A

tp determine if there is a statistically significant association btw distribution of 2 species

applied to quadrat sampling

CAN ONLY USE IF > (or equal to) 5 frequency & random sample

26
Q

What are the steps to the chi square test?

A
  1. hypothesis (null / alternative)
  2. table of frequencies (observed & expected)
  3. formula
  4. degree of freedom (fd)
  5. ‘p’ value
27
Q

What does the hypothesis step of the chi square test consist of?

A

null (H0)
2 species INDEPENDENTLY distributed

alternative (H1)
2 species associated POSITIVELY or NEGATIVELY

28
Q

What does the table of frequencies step of the chi square test consist of?

A

make a table of observed frequencies

make a table of expected frequencies using formula:
(row total x column total) / grand total

29
Q

What does the chi squared formula step of the chi square test consist of?

A

apply formula and insert calls into the TOTAL areas

formula:
x^2 = (sum of (O - E) ^2) / E

O = observed frequency
E = expected frequency
30
Q

What does the degree of freedom step of the chi square test consist of?

A

mathematical restriction the designates what range of values fall within each significant level

df = (m - 1) (n - 1)

m = # rows
n = # columns

when distribution patters for 2 species compared : D SHOULD ALWAYS = 1

31
Q

What does the ‘p’ value step of the chi square test consist of?

A

determines if result is statistically significant (< 5% probability = p < 0.05)

Biology (15 decks)

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