Bio L6 (4) Classification and evolution > Ecology > Flashcards

Ecology Flashcards

(73 cards)

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1
Q

Define community.

A

An interacting group of various species in a common habitat.

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2
Q

Define population.

A

The number of organisms of the same species that live in the same geographical area at the same time.

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3
Q

List abiotic factors which can affect a population:

A
  • Light
  • pH
  • Water / Humidity
  • Temperature
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4
Q

When would you use an open frame quadrat?

A

When studying larger organisms.

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5
Q

How do you assess species richness and species evenness.

A

Species diversity index.

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6
Q

What different parts of biodiversity can be studied.

A

Species richness, species evenness.

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7
Q

Define niche.

A

The match of a species to a specific environmental condition.

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8
Q

What is biodiversity.

A

Every living organism within an ecosystem or habitat, it can be global or local.

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9
Q

Define ecosystem.

A

A community of living organisms in conjunction with the non-living components of their environment.

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10
Q

Define habitat.

A

A place where an organism or community of organisms live including all biotic and abiotic factors of the surrounding environment.

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11
Q

When would you use a gridded frame quadrat?

A

When studying small organisms.

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12
Q

What is the equation used in a capture-recapture method?

A

no. individuals caught in first sample x no. marked caught in second sample / No. recaptured

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13
Q

How do you calculate human birth rate?

A

(population change during a period / population at the start of a period) x 100

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14
Q

Describe the predator-prey relationship:

A
  • Predators eat their prey, thereby reducing the population of the prey
  • With fewer prey available, the predators are in competition with one another for the prey that is still left
  • Predator population decreases due to some predators not being able to catch enough prey
  • With fewer predators around, fewer prey are consumed
  • Prey population increases
  • More prey available, predator population also increases
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15
Q

What assumptions can be made during a capture-recapture method?

A
  • Proportion of marked/unmarked individuals is the second sample is the same for the whole population
  • Individuals in the first sample distribute themselves evenly
  • The population has a definite boundary. (no immigration/migration)
  • Birth/Death is low
  • Marking method is not toxic/ conspicuous
  • Marking is not lost
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16
Q

When would you use a point quadrat?

A

When studying extremely small organisms.

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17
Q

What is primary succession?

A

Occurs in any newly formed area where no life previously existed, the process is slow and takes hundreds of years.

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18
Q

What makes a good pioneer species?

A
  • Asexual reproduction.
  • Wind-dispersed seeds.
  • Rapid germination.
  • Photosynthesis ability.
  • Nitrogen fixing capacities.
  • Tolerance to harsh conditions.
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19
Q

Why is the process of succession highly complex?

A

There are many situational factors which affect an ecosystem.

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20
Q

What is secondary succession?

A

Occurs in an environment when life is already present, but has been altered in some way (e.g. natural disaster).

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21
Q

What is the difference between the speed of primary and secondary succession?

A

Changes are fastest in secondary succession as there are often seeds present already.

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22
Q

What factors are most influential early in succession?

A

Abiotic factors.

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23
Q

How do pioneer species arrive in an environment?

A

Haphazardly, there is no method or organisation. Organisms which are most tolerant of conditions will survive, others will die.

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24
Q

What is a plagioclimax?

A

An area in which human influences have prevented the ecosystem from developing further.

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25
When is an ecosystem said to be in equilibrium?
When it is a climax community.
26
In ecology, how do you conduct a random sample?
- Lay out two long tape measures at right angles along two sides of the study area. - Obtain a series of coordinates by using random number generators. - Place the qaudrat at these intersections and record species measures.
27
Once a pioneer species is present, what factors become increasing important?
Biotic factors.
28
What is the carrying capacity of a population?
The number of organisms in the population that can be sustained over a relatively long time period.
29
What is the difference between abiotic and biotic factors with examples:
Abiotic = sterile / non-living factors: - Temperature, Light, pH, Humidity. Biotic = live factors: - Animals for predation, Predators, Pathogens.
30
What is the log phase?
The stage of exponential growth where ideal conditions are present and maximal growth rate is reached.
31
What is the lag phase?
The stage where cell are metabolically active, however, only increase in cell size rather than organism numbers.
32
What are the two types of competition?
``` Intraspecific = members of the same species. Interspecific = members of different species. ```
33
What is the difference between a predator and a prey?
A predator is an organism which feeds on another organism. | A prey is an organism which is consumed by other organisms.
34
The predator-prey relationship is an example of which type of competition?
Interspecific competition.
35
Explain how the predator-prey relationship creates a selective pressure:
The relationship causes periodic population crashes where competition is high, this means only the "best" individuals survive and the populations evolve over time.
36
Explain the predator-prey relationship:
Predators consume the prey causing prey numbers to decrease, however, there is then intraspecific competition increases causing predator populations to decrease, allowing prey numbers to increase as there is less predation...
37
What is the law of thermodynamics?
Energy cannot be created nor destroyed, when converted between stores some energy is lost to heat.
38
What is the equation for energy flow in ecosystems?
GPP = NPP + R
39
What is GPP?
Gross Primary Productivity = the total energy initially captured.
40
What is R?
Respiratory Loss = energy lost through respiration.
41
What is NPP?
Net Primary Productivity = biomass for growth and reproduction.
42
What percentage of the GPP is lost to respiration?
25% - 50%.
43
What is biomass?
The total dry mass of living material in a given area at a given time.
44
How is biomass measured?
Calorimetry -> burn it and measure the temperature increase to work out the energy released into it.
45
What is the equation for net production of consumers?
N = I - ( F + R) | Net production of consumers = Ingested biomass - (Biomass in excretory products + Respiratory losses)
46
What is the relationship between the trophic levels and energy passed through an ecosystem?
The fewer trophic levels, the more energy passed through.
47
How can efficiency of food production be increased?
- Genetic mutation / Selective breeding -> shorter growth periods or higher crop yields. - Factory farming -> less energy loss through respiration. - Monoculturing -> reduces competition leading to higher NPP.
48
What is the rough transfer of energy through a trophic level?
Roughly 10%.
49
What is the origin of genetic variation?
Recombitance in meiosis, shuffles alleles between homologous chromosomes.
50
What is stabilising selection?
Selection pressure that favours an intermediate phenotype.
51
What are the different types of selection?
- Stabilising selection. - Directional selection. - Disruptive selection.
52
Human birth mass is an example of which type of selection?
Stabilising selection, babies born within the 2.7 and 4.0 kg ranges are most likely to survive and reproduce.
53
What is directional selection?
Individuals with an advantageous allele are more likely to survive and reproduce.
54
What causes a directional selection?
When a new selection pressure is introduced into the environment (such as increased temperature) is applied to the population.
55
Warfarin resistance in rats is an example of which type of selection?
Directional selection, warfarin resistant animals are more likely to survive.
56
When does disruptive selection occur?
Occurs when groups from a single original population are exposed to different selection pressures.
57
What are the different types of disruptive selection?
Allopatric and Sympatric.
58
What is allopatric selection?
Occurs when populations are separated by a geographical or physical barrier.
59
What is sympatric selection?
Occurs without physical separation of the two groups from the same population.
60
What is meant by polymorphism?
It occurs during disruptive selection where different alleles are advantageous in each small population causing seperate allele frequency.
61
Why does disruptive selection require reproductive isolation?
So that gene pools can be maintained and specialisation can occur.
62
Banded snails are an example of which type of selection?
Disruptive selection, yellow snails are better camouflaged in grassland, brown snails are better camouflaged in woodlands.
63
Which type of selection results in bimodal evolution?
Disruptive selection.
64
How can antibiotic resistance evolve?
- Mutations, - Vertical gene transfer, - Horizontal gene transfer.
65
What is bimodal evolution?
Where intermediate forms are no longer favoured.
66
What is horizontal gene transfer?
Conjugation and Transduction.
67
What is vertical gene transfer?
Binary fission, non-resistant ones die and genes become more prevalent.
68
What is the equation that compares species diversity?
Simpson's Index. | D = N(N-1) / Sum n(n-1)
69
How can we balance agricultural needs and conservational needs?
High impact conservation strategies, grants to support farmers and consumer awareness.
70
What affects the carrying capacity of a certain species in a habitat?
- Abiotic factors. | - Interspecific and intraspecific competition and predation.
71
What methods can be used to estimate the size of a population in a habitat?
- Capture-recapture - Randomly placed quadrats - Quadrats on a belt transect
72
What organisms are involved in colonisation?
Pioneer species.
73
What is a biosphere?
An artificial structure enclosing a self-contained ecosystem or ecosystems.
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