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Biology 1A > 8. Ecology > Flashcards

8. Ecology Flashcards

1
Q

What is a population?

A

Group of individuals of the same species living in a general area

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2
Q

What is population ecology?

A

The study of factors affecting the size of a population

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3
Q

What 4 main factors affect the size of a population?

A

Births

Deaths

Emigration

Immigration

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4
Q

How can populations change over time (general trends)?

A

Grow to reach a stable size

Fluctuates irregularly

Rise and fall in regular cycles

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5
Q

What is intra-specific comeptition?

A

Competition for resources between between members of the same population / species

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6
Q

What is inter-specific competition?

A

Competition for resources between between members of different population / species

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7
Q

True or false: Populations have structure

A

True. Structured by age, sex and spatial structure.

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8
Q

True or false: Populations are unregulated

A

False. Populations are regulated.

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9
Q

True or false: Populations don’t generally change over time

A

False. Populations are dynamic over time

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10
Q

What is a survivorship curve?

A

A plot of the proportion of a cohort still alive at each age.

This shows the pattern of survivorship for a population

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11
Q

How many survivorship curves are there and what are they called?

A

3 - Type I, II, III

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12
Q

Describe the environment that type I organisms may be found

A

Mortality highest in older age classes

Found in long lived species

Living in a stable environment

Iteroparous (reproduction spread throughout lifetime)

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13
Q

Describe the environment that type II organisms may be found

A

Mortality constant throughout life

Found in short-medium lived species

Living in a relatively stable environment

Iteroparous (reproduction spread throughout lifetime)

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14
Q

Describe the environment that type III organisms may be found

A

High mortality in juveniles

Short lived species

Often semelparous - reproduction in a single breeding event

Unpredictable and temporary environments

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15
Q

Describe the type I survivorship curved

A
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16
Q

Describe the type II survivorship curved

A
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17
Q

Describe the type III survivorship curved

A
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18
Q

What does it mean for a species to be intermediate in survivorship

A

Do not fit in perfectly to each type of survivorship as they can show more complex patterns.

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19
Q

True or false: Survivorship patterns for the same species will always be the same

A

False: Survivorship curves can differ among populations within a single species

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20
Q

What can population pyramids be used to visualise?

A

Population structure by age and sex

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21
Q

What is spatial structure of a population?

A
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22
Q

How can organisms be dispersed?

A

Random dispersion

Uniform dispersion

Clumped dispersion

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23
Q

Describe random dispersion

A

Position of each individual is independent of other individuals

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24
Q

What causes random dispersion?

A

Occurs in the absence of strong competition or constant distribution of key physical or chemical factors

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25
Q

Describe uniform / regular dispersion

A
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26
Q

What causes uniform dispersion?

A

seeking ideal factors

territorial animals

planted crops

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27
Q

Describe clumped dispersion

A

Individuals aggregate in patches

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28
Q

What causes clumped population

A

Aggregate in areas of high resource availability or favourable physical conditions

Mating behaviour and group predation or defence against predators can also influence clumped dispersions

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29
Q

Define population growth

A

The rate of change at each instant in time

dN/dt = rN

(where r = per capita change in population size, N at each instant in time)

r = intrinsic rate of increase

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30
Q

When is it most likely to see exponential population growth?

A

Exponential population growth occurs under ideal conditions; all individuals have access to abundant food and reproduce at physiological capacity.

This could be when populations are introduced to a new environment or when a population is rebounding after drastic reduction by a catastrophic event

31
Q

Describe exponential growth

A

Populations increase in size by a constant proportion at each instant

32
Q

What is the logistic population growth model

A

dN/dt = rN x (K - N)/K

K = carrying capacity

33
Q

How will population growth be affected when N is small?

Use the logistic population growth model:
dN/dt = rN x (K - N)/K

A
34
Q

How will population growth be affected when N is large and resources are limiting?

Use the logistic population growth model:
dN/dt = rN x (K - N)/K

A
35
Q

How will population growth be affected when N equals K?

Use the logistic population growth model:
dN/dt = rN x (K - N)/K

A
36
Q

Describe the graph of exponential growth

A
37
Q

Describe the graph of logistic growth

A
38
Q

SLIDE 31 and 32

A
39
Q

What could conservation biologists use the logistic growth model for? (3 examples)

A

Predicting rate of recovery for small populations

Estimating sustainable harvest rates for wildlife

Estimating the critical size below which populations become at risk for extinction

40
Q

Slide 33 density dependent regulation

A
41
Q

List some density dependent factors

A

LISTEN TO WHAT HE SAYS

Competition for resources

Territoriality

Disease

Intrinsic factors

Toxic wastes

42
Q

slide 35 density independent

A
43
Q

True or false: Both density dependent and density independent factors can operate on populations to regulate them

A

True

44
Q

True or false: Regulation differs between populations

A

True

45
Q

True or false: A population can survive with only density independent regulation

A

False. There must be some density dependent element or population will become extinct

46
Q

True or false: SLIDE 36 just check you have everything and then add it to the regulation flashcard at the top

A
47
Q

What is the study of population dynamics

A

The study of complex interactions between biotic and abiotic factors that cause variation in population size

48
Q

What are population cycles used to visualise?

A

Population dynamics

49
Q

State 4 reasons as to why we should conserve nature

A

Ethical/moral reason to save species

Nature provides ‘ecological services’

Human activities threaten biodiversity

Conservation biology conserves biological diversity

50
Q

What are ecosystem services?

A

The processes by which natural ecosystems help sustain human life

51
Q

What are the four main categories of ecosystem services

A

Provisioning

Regulating

Supporting

Cultural

52
Q

Give examples of regulating ecosystem services

A
53
Q

Give examples of supporting ecosystem services

A
54
Q

Give examples of cultural ecosystem services

A
55
Q

Give examples of provisioning ecosystem services

A
56
Q

What are the three components of biodiversity?

A

Genetic diversity

Species diversity

Ecosystem diversity

57
Q

What is species diversity?

A

The number of species in an ecosystem or across the biosphere

58
Q

Describe the modern-day latitudinal biodiversity gradient

A

Distribution of species showing the high concentration of diversity inequatorial regions, declining polewards

59
Q

What are the three models used to explain declining polewards biodiversity and higher tropical diversification rates?

A

Tropics as cradle model

Tropics as museum model

Out of the tropics model

60
Q

Describe the tropics as cradle model

A

Origination rates are higher in tropical areas and extinction rates do not vary with latitude

61
Q

Describe the tropics as museum model

A

Origination rates are constant with latitude, but extinction rates are lower in the tropics

62
Q

Describe the out of the tropics model

A

Origination rates are higher and extinction rates are lower in tropical areas, and species movement is higher from the tropics to the extratropical areas.

63
Q

What are the five major threats to biodiversity (causing biodiversity loss)?

A

Habitat loss

Introduced species

Overharvesting

Global change

Invasive alien species

64
Q

List some examples of habitat loss by human alteration

A

Agriculture

Forestry

Urban development

Mining

Pollution

65
Q

How do invasive alien species impact nature?

A

Change ecosystems

Predation and herbivory

Compete with native species

66
Q

What is overharvesting?

A

Harvesting of organisms at rates exceeding the ability of their populations to rebound

67
Q

Which species are most vulnerable to overharvesting?

A

Species with restricted habitats

68
Q

REWATCH THIS BIT How does global change reduce Earth’s capacity to support life?

A

Climate change

Atmospheric chemistry

Major ecosystem change

69
Q

SLIDE 24 REWATCH

A
70
Q

What is a biodiversity hot spot?

A

It is a relatively small area with numerous endemic (found nowhere else) and many endangered and threatened species

71
Q

What are nature-based solutions (Nbs), for conserving biodiversity?

A
72
Q

Rewatch slide 27, 28, 29, 31

A
73
Q

UK Legislation SLIDE 31

A

National Legislation

European Union Directives or other European initiatives implemented in UK legislation

Protected areas set up under Global Agreements Ramsar (Wetland) sites

Marine Protected Areas

74
Q
A

Biology 1A (9 decks)

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