Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

life sciences gr 11 > population ecology > Flashcards

population ecology Flashcards

1
Q

define demography

A

it is the statical study of a population, such as population density, population distribution, and population growth rate, which depends on factors such as mortality patterns and age distribution of the population

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is population ecology

A

it is the part of s ecology that focuses on the factors influencing the population size, growth rate, growth forms, and distribution of individuals inside a population

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is species

A

it is a group of organisms with familiar characteristics, which produces fertile offspring

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is a population

A

it is a group of organisms of the same species that are found in a particular area and cross breed freely

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is a community

A

ait is a group of populations occurring in a specific area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

define ecosystem

A

a unit of plant and animal communities living in interaction with each other as well as with the abiotic factors in a particular area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is an environment

A

it is the external factors, biotic and abiotic surrounding an organism and influencing its development and survival

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

define a habitat

A

it is the specific environment in which a plant or animal species normally occurs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is a population distribution

A

is the pattern of distribution of the individuals of the population in the area where the population lives

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what are reasources

A

they are abiotic and biotic components of an environment that supports and maintains and environment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what are limiting factors

A

thet are those environmental factors that that specifically determines where an organism lives or occurs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

population distribution are often described by one of 3 tearms

A

uniform, random,clumped

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

define what a population size is

A

it is the total number of individual in in a population

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what is population density

A

it is the number of individuals of a population per unit area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what are the factors that influences population size

A

natality,mortality,migration-immigration and emigration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what is natality

A

birth rate of a population

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what is mortality

A

death rate of a population

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what is immigration

A

it is the one-way movement of organisms into an area where they became established

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what is emigration

A

it is the one-way movement of organisms out of an area to become established

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

how to calculate population change

A

POPULATION CHANGE = ( Number of births + Immigration) - (Deaths + emigration)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what are density dependent factors

A

they are factors that have a direct correlation to the size of the population in an area. The greater the size of the population, the greater the influence of these factors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what are density independent factors

A

they are factors which exert an influence on a population regardless its size

23
Q

how does the density dependent and independent factors contribute to fluctuations in population size

A

these factors increase environmental resistance limiting the population growth altogether

24
Q

types of environmental resistance

A
  • Carrying capacity
  • Density dependent factors
  • Density independent factors
25
Q

what is a stable population size

A

it is when the population size fluctuate in natural population around the carrying capacity

26
Q

what is a close population

A

it is a population where immigration and emigration do not occur

27
Q

what is meant by carrying capacity

A

it is the number of individuals an environment can support in a specific season

28
Q

how 2 ways to determine a population size

A
  1. Direct counting techniques-determines the actual population sizes by counting all individual sin a population mostly those who are slow moving and sessile
  2. Indirect counting techniques- determines an estimation of the population size where it is difficult to determine the actual number of the organisms, by counting only a part of the population
29
Q

3 direct counting techniques

A
  1. census e.g human population
  2. counting e.g by the aid of a helicopter
    3, aerial photos of groups of animal
30
Q

2 indirect counting technique

A
  1. mark and recapture

2. quadrants

31
Q

explain how the mark and recapture indirect counting technique occurs

A
  • 1 st sample in caught, counted, marked and then released
  • Adequate time is allowed for the population to mix with the rest of the population
  • 2nd sample is captured. the number of marked and unmarked organisms are counted. The petersen index is used to determine the size of the population
32
Q

How is the petersen index calculated

A

PETERSEN INDEX: N = M * C /R

N- estimated population size
M- total number of animals in the 1st sample
C- total number of individuals captured in the 2nd sample
R- number of marked individuals in 2nd sample

33
Q

how can the mark-recapture techniques be improved /made more accurate

A

by repeating the the sampling a few times and then calculating an average population size

34
Q

precautions to take to ensure reliable results for the mark-recapture technique

A

+ sample must be large enough to truly represent a population
+ markings used must remain for the entire period of the procedure
+ marking must be suitable for the type of organism and not harm or interfere with its movement or behavior
+ marked organisms should be released into an environment close to the site of capture and given enough time to mix

35
Q

example of marking

A

number,ring,electronic tag,collar, paint

36
Q

what are quadrats

A

Quadrats refer to the square frames made of plastic,wood, or string that are placed randomly on an area containing the organism. It works for sdentary animals and small plants

37
Q

how is population size calculated in quadrats

A

POPULATION SIZE= average number of individuals per quadrat * surface area of land / quadrant surface area

38
Q

precaution to take to ensure that reliable results of the quadrant indirect counting method

A
  • several quadrats samples should be made to determine the average number of individual per quadrants
  • quadrants samples must be done randomly throughout the total area
  • the procedure should be repeated several times and the average number of organisms per quadreat calculated
39
Q

2 different growth patterns

A

j shaped geometric or growth curve AND

S-shaped or logistic growth curve

40
Q

Geometric growth is characterised by microorganisms such as bacteria fungi and protists. Explain how this occurs

A

occurs when a population reaches its max possible growth rate as it would have reproduced quickly and doubled its number due favourable condition.Eventually their resources becomes limited causing death or extinction level

41
Q

three distinct phases in geometric growth curve

A

lag phase,geometric phase and death/extinction phase

42
Q

lag phase

A

Population number increases slowly because:

  • individuals may still be acclimatising to their environment
  • they need time to find their mates
  • most of the population is sexually immature
43
Q

geometric [accelerated] growth phase

A

individuals have acclimatised and many reproducing offspring exits and in favourable conditions produces many offsprings. Birth rate is > Death rate

44
Q

extinction or death phase

A

resources becomes limited and the population is no longer reproducing effectively. Mortality rate is > Nationality rate thus population decrease rapidly

45
Q

Logistic S-shaped growth

A

normally occurs in high order organisms such as mammals which normally reproduces slower

46
Q

an S-shaped forms typically consists of 5 phases

A

lag phase, exponential phase, decelerating growth phase, equilibrium phase and death/ extinction phase

47
Q

lap phase in logistic growth form

A

the population increases slowly because
*population acclimatises and adapt to environment
* individuals must become sexually immature
*individuals seek time for mating
incubation period

48
Q

exponential or accelerating growth phase in logistic growth form

A

population reaches a higher natality level due to more sexually mature individuals procreating and low environment resistance.Natality is > Mortality

49
Q

Decelerating phase in logistic growth form

A

Mentality is still > Mortality BUT Mortality is gaining momentum due to high levels of environmental resistance

50
Q

Equilibrium or stationary phase in logistic growth form

A

The population numbers now reach the carrying capacity of the environment and stabilizes around this value. Natality and Mortality are approximately equal

51
Q

What is carrying capacity

A

the maximum number of individuals that an specific environment can sustain

52
Q

Death or Extinction phase in logistic growth form

A

Some populations cannot regulate their resource usage and/or changes to abiotic and biotic factors in their environment and are then unable to sustain life

53
Q

define a stable population

A

population where the numbers fluctuate round the carrying capacity

54
Q

define an unstable population

A

when the population numbers far exceed the carrying capacity the habitat will most likely be damaged resulting in a decrease in the carrying capacity

life sciences gr 11 (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions