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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
Describe uniform / regular dispersion
26
What causes uniform dispersion?
seeking ideal factors territorial animals planted crops
27
Describe clumped dispersion
Individuals aggregate in patches
28
What causes clumped population
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
29
Define population growth
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
30
When is it most likely to see exponential population growth?
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
Describe exponential growth
Populations increase in size by a constant proportion at each instant
32
What is the logistic population growth model
dN/dt = rN x (K - N)/K K = carrying capacity
33
How will population growth be affected when N is small? Use the logistic population growth model: dN/dt = rN x (K - N)/K
34
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
35
How will population growth be affected when N equals K? Use the logistic population growth model: dN/dt = rN x (K - N)/K
36
Describe the graph of exponential growth
37
Describe the graph of logistic growth
38
SLIDE 31 and 32
39
What could conservation biologists use the logistic growth model for? (3 examples)
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
Slide 33 density dependent regulation
41
List some density dependent factors
LISTEN TO WHAT HE SAYS Competition for resources Territoriality Disease Intrinsic factors Toxic wastes
42
slide 35 density independent
43
True or false: Both density dependent and density independent factors can operate on populations to regulate them
True
44
True or false: Regulation differs between populations
True
45
True or false: A population can survive with only density independent regulation
False. There must be some density dependent element or population will become extinct
46
True or false: SLIDE 36 just check you have everything and then add it to the regulation flashcard at the top
47
What is the study of population dynamics
The study of complex interactions between biotic and abiotic factors that cause variation in population size
48
What are population cycles used to visualise?
Population dynamics
49
State 4 reasons as to why we should conserve nature
Ethical/moral reason to save species Nature provides 'ecological services' Human activities threaten biodiversity Conservation biology conserves biological diversity
50
What are ecosystem services?
The processes by which natural ecosystems help sustain human life
51
What are the four main categories of ecosystem services
Provisioning Regulating Supporting Cultural
52
Give examples of regulating ecosystem services
53
Give examples of supporting ecosystem services
54
Give examples of cultural ecosystem services
55
Give examples of provisioning ecosystem services
56
What are the three components of biodiversity?
Genetic diversity Species diversity Ecosystem diversity
57
What is species diversity?
The number of species in an ecosystem or across the biosphere
58
Describe the modern-day latitudinal biodiversity gradient
Distribution of species showing the high concentration of diversity in equatorial regions, declining polewards
59
What are the three models used to explain declining polewards biodiversity and higher tropical diversification rates?
Tropics as cradle model Tropics as museum model Out of the tropics model
60
Describe the tropics as cradle model
Origination rates are higher in tropical areas and extinction rates do not vary with latitude 
61
Describe the tropics as museum model
Origination rates are constant with latitude, but extinction rates are lower in the tropics 
62
Describe the out of the tropics model
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
What are the five major threats to biodiversity (causing biodiversity loss)?
Habitat loss Introduced species Overharvesting Global change Invasive alien species
64
List some examples of habitat loss by human alteration
Agriculture Forestry Urban development Mining Pollution
65
How do invasive alien species impact nature?
Change ecosystems Predation and herbivory Compete with native species
66
What is overharvesting?
Harvesting of organisms at rates exceeding the ability of their populations to rebound
67
Which species are most vulnerable to overharvesting?
Species with restricted habitats
68
REWATCH THIS BIT How does global change reduce Earth's capacity to support life?
Climate change Atmospheric chemistry Major ecosystem change
69
SLIDE 24 REWATCH
70
What is a biodiversity hot spot?
It is a relatively small area with numerous endemic (found nowhere else) and many endangered and threatened species
71
What are nature-based solutions (Nbs), for conserving biodiversity?
72
Rewatch slide 27, 28, 29, 31
73
UK Legislation SLIDE 31
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

Biology 1A (9 decks)

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