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Bio YR11 > Chapter 5 > Flashcards

Chapter 5 Flashcards

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Biology 101 flashcards
1
Q

Define population

A

A group of individuals belonging to the same species living in a particular area at the same time

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2
Q

Why is it important for scientists to know the size of a population?

A

To understand the habitats and needs of organisms. This enables humans to sustain and ensure that vulnerable species persist and contribute to the planets biodiversity

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3
Q

Define r selection

A

species quickly colinising an unstable ecosystem, leading to a pattern of rapid population increase and decrease and eventual take over by competitors

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4
Q

what is a r-selected species

A

A fast growing and reproducing organism, often the first to occupy unused resources and living space

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5
Q

What are the characteristics of an r selected species

A

Smaller size, short life cycles and a lack of parental care in young

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6
Q

What are some examples of an r selected species

A

Mice, rats, frogs, toads, weeds and oysters

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7
Q

Define k selection

A

While some individuals may not survive initially, over the long term a sustainable population can be maintained

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8
Q

What is k selected species

A

A slow growing, long lived species typical of those in a climax community

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9
Q

What are the characteristics of a k selected species

A

Live longer, breed later, have fewer offspring and devote their lives to ensuring the survival of offspring

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10
Q

Examples of a k selected species

A

birds, larger mammals and larger plants.

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11
Q

Define carrying capacity

A

The maximum population size of a species that can be supported in a given environment

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12
Q

What is the equation for population growth rate?

A

Population growth rate = (Birth rate + Immigration rate) - (death rate + emigration rate)

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13
Q

Explain the equation that calculates population growth rate

A

A population is increasing if the birth/immigration rate exceeds the death/emigration rate. Therefore, a population decreases when the death/emigration rate exceeds birth/immigration rate

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14
Q

What is an open ecosystem

A

Where migration between populations of animals can occur but will affect the overall numbers in the ecosystem involved

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15
Q

What is a closed ecosystem

A

Where migration doesn’t impact population size at all

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16
Q

What is random distribution and an example

A

When organisms are spaced irregularly, the location of an organism does not affect the location of another. EG. Specific tree species in a forest.

17
Q

what is uniform distribution

A

Organisms are evenly spaced, the presence of one organism determines how close another will be. Common in high density populations like Penguins

18
Q

What is clumped distribution

A

A number of individuals are grouped together which make up the population as a whole

19
Q

Why is knowing the distribution of a species important

A

Knowledge of particular plant species can give glues about the distribution and abundance of animals that depend on them

20
Q

Disadvantages and advantages of direct observation

A
  • Time consuming, dangerous

+ Satellites can be used in inaccessible regions

21
Q

What is direct observation

A

A method used to measure abundance. Eg, recording sightings at particular intervals

22
Q

What is a quadrat and the advantages and disadvantages

A

Where a square is placed on the ground to count each individual of a species. Useful for stationary organisms and faster. Needs to have appropriate number of quadrats, wont be accurate

23
Q

Population size equation

A

Total number of individuals counted / area of each quadrat x number of quadrats

24
Q

What is a transect and their advantages and disadvantages

A

Where a line is drawn through a community to determine the distribution of species. Get a good picture of the landscape over a distance. Can’t be used in marine ecosystems and if a large sampling interval is used, wont be accurate

25
Q

What is the capture mark recapture method and their advantages and disadvantages

A

When individuals are captured, marked and released and after time are recaptured to indicate population size.
Easier than sampling every single member of the population
Time, costly, species die, needs large sample size

26
Q

Equation for capture mark recapture

A

Total population = Number marked in first sample (M) x Number of animals recaptured (n) divided by number of recaptured animals that are marked (m)

27
Q

Advantages and disadvantages of telemetry

A

Shows pattern and behavior of animals

Time consuming and costly

28
Q

What is species distribution modeling

A

An attempt to predict future needs and resource management using computer technology

29
Q

What is an example of the carrying capacity theory

A

100 km^2 of eucalyptus forest is the minimum area possible to support 10 000 sugar gliders as a viable population. This info acts as a guide to the minimum size a park or any closed ecosystem needs to be to conserve animals. The area needs to be sufficient for a significant number of top carnivores to survive

30
Q

What is environment resistance

A

Happens when populations exceed carrying capacity. Leads to competition, disease, parasites, increase in predation, decrease in food supply

31
Q

What are density dependent factors

A

The greater the density of a population, the more individuals die or fail to reproduce. Eg. Competition, disease, parasites, predation, food supply

32
Q

What are density independent factors

A

Those that affect all individuals in a population regardless of age or stage. Eg, severe weather, volcanic activity, habitat destruction

33
Q

When is controlling populations needed

A

When one species increases at the expense of others. Can be controlled chemically or biologically

34
Q

What is chemical control

A

The chemical pesticides used to control pest species. Quick and effective but can be ecologically damaging and costly

35
Q

What is biological control

A

When living organisms are used to control pest species

36
Q

What are the four types of biological control

A
  1. General predators - Organisms that consume a great variety of pest species. Eg, ladybirds target aphids, caterpillars, mites and beetles
  2. Specialized predators - Organisms that target one pest species. Eg, dragonflies and mosquitoes
  3. Parasites - organisms that lay their eggs in the bodies of hosts. Eg, wasps, flies
  4. Microbial diseases - caused by bacteria, fungi and viruses that target species and cause death through illness
37
Q

Example of unsuccessful biological control

A

Cane toads were introduced to north east Queensland to control cane sugar beetle pests. Cane toads have rapidly expanded north and south of the original site

38
Q

Successful biological control

A

Wasps are being used to control the native stem-girdler moths that can decimate crops in Queensland. The wasps lay their eggs in the moth eggs, which are then consume by the wasp larvae

39
Q

Pest

A

Any species causes harm or death to other organisms

Bio YR11 (13 decks)

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