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Bio Y13 > 3.7.4 Ecosystems (C19) > Flashcards

3.7.4 Ecosystems (C19) Flashcards

1
Q

define community

A

all living organisms of all species found in a given area/habitat/ecosystem at a given time

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2
Q

define ecosysytem

A

self contained area including all the living (all the communities within it) and non living factors interacting with one another

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3
Q

define niche

A

describes how an organism fits into the environment/its role in the ecosystem - no organism can occupy the same niche

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4
Q

define succession

A

used to describe changes that occur over time, in the species that occupy a particular area

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5
Q

define abiotic

A

non living factor in the environment of an organism e.g temperature, oxygen concentration, pH, light

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6
Q

define biotic

A

the living factors in the environment of an organism e.g. disease, predation, competetion

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7
Q

define population

A

all of the organisms of one particular species in a given habitat/area at the same time

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8
Q

What conditions are necessary in order for the mark release recapture investigations to be valid? what assumptions are made?

A
  1. markings dont make organism visible to predators
  2. markings dont harm the organism
  3. No migration/immigration
  4. sample large
  5. no reproduction
  6. no births or deaths
  7. markings are nor easily rubbed off/worn off
  8. marked individuals in 1st sample distribute themselves evenly back into the population
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9
Q

Name two types of competition

A

interspecific and intraspecific

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10
Q

Define intraspecific competition

A

competition between organisms of the SAME species

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11
Q

Define interspecific competition

A

competition between organisms of DIFFERENT species

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12
Q

What is a pioneer species?

A

the first organism to colonise in the first stage of succession - it can with stand hostile environments

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13
Q

define a climax community

A

A stable community/no further succession.

All the organisms that make up the final stage of succession - animals and plants

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14
Q

define a habitat

A

place where an organism lives

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15
Q

define carrying capacity

A

The population size of a species that an be supported by the ecosystem

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16
Q

within an ecosystem which 2 major processes occur

A
  1. flow of energy through the system

2. recycling of nutrients within the system

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17
Q

define population size

A

the number of individuals in the population

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18
Q

what do we call factors that limit the size of the population

A

limiting factors - they can be abiotic or biotic

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19
Q

Give examples of abiotic factors that limit the size of a population

A

light, temperature, pH, water, humidity

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20
Q

give examples of biotic factors that limit population size

A

availability of food, predation, disease

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21
Q

The growth and size of the human population depends on

A

birth rate v death rate - its the balance between these two that determines if if increases, decreases or remains the same (also includes immigration and migration)

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22
Q

define immigration

A

when people move into a population from outside

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23
Q

define emmigration

A

when people move out of a population and leave

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24
Q

In a stable population what can be said about birth and death rates?

A

they are equal

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25
In an increasing population what can be said about birth and death rates?
birth rates are higher than death rates
26
define predation
where one organism is consumed by another
27
Define prey
An organism that is consumed/hunted by another organism
28
Define a predator
An organism that hunts and feed on other organisms
29
Why is it impossible to count every organism when investigating populations?
too many to count, too time consuming, would probably damage the habitat
30
How do we ensure the samples we take are representative when investigating populations
Take large sample, sample at random
31
Name two types of quadrats
frame and a point
32
How does a point quadrat work?
A long pin is dropped along a horizontal bar at set intervals and the organism record that touches the pin
33
How does a quadrat work?
placed at various locations at random and the abundance of each species within the quadrat is then recorded
34
Describe how you sample at random
1. lay out 2 tape measures at right angles along the area to study 2. obtain a set of coordinates by a random number generator 3. place the quadrat at the intersection of the coordinates and record the species present
35
define abundance
the number of individuals of each species in a given area
36
Abundance can be measured in two ways
1. frequency | 2. % cover
37
To ensure your results are reliable and representative you should
make sure your sample size is large
38
What does the mark release recapture technique allow you to do?
estimate the population size of organisms that move
39
state the formula for mark release recapture
est pop size = (total no of organisms in 1st sample x total number in 2nd sample)/ number of marked organisms recaptured.
40
Name the first species to colonise in the first stage of succession
pioneer species - they an withstand the hostile growing environment
41
What features might pioneer species have that make them able to colonise
1. reproduce asexually 2. produce a vast amount of wind dispersed seeds/spores that an reach isolated areas 3. rapidly germinating seeds 4. ability to photosynthesise 6. ability to fix nitrogen 7. tolerance to extreme conditions
42
Name pioneer species example capable of surviving inhospitable conditions
lichens
43
What species follows after lichens - why?
Mosses - this is because the environment becomes more hospitable, abiotic factors are changing
44
What species follows after mosses in succession?
ferns
45
How does succession impact on animals?
they have undergone successional changes too - largely determined by the different types of plants available for food and habitats!
46
The common features of succession include
1. abiotic environment becomes less hostile 2. greater number of and variety of habitats and niches 3. increased biodiversity 4. Increased variety of food sources 5. more complex food webs 6. increased biomass
47
Name the two types of succession
primary and secondary
48
what is the difference between primary and secondary succession
primary - bare land - no soil - takes longer to reach a climax community secondary succession - felled areas - soil present - climax community reached sooner/more quickly
49
what is conservation?
The management of the earths natural resources by humans for the future
50
What does conservation of habitats involve?
active human involvement
51
What are the main reasons for conservation?
1. maintain our planet 2. Other species have occupied the planet longer than we have - respect 3. living organisms contain a huge pool of genes that can make useful products/substances - could prove valuable in the future 4. Habitats and organisms enrich our lives and many people find inspiration from them
52
what do you call the maximum stable population size of a species that an ecosystem can support?
carrying capacity
53
A predator is...
an organisms which kills and eats other organisms
54
predator and prey populations are said to be...
linked - when one increases the other increase (shortly after)..
55
what is a quadrat?
a square frame enclosing a given area
56
what equipment can you use to investigate non-motile organisms (e.g. plants and limpets)
quadrats and transects
57
What technique do you use to investigate motile organisms?
mark release recapture
58
What is species frequency?
How often a species is found
59
What would you set up if you wanted to investigate changes in plant distribution and environmental factors?
transect - place quadrat at regular intervals along the length and determine % cover (of chosen plant). Measure the environmental factor at that point too
60
Succession is...
how an ecosystem changes with time
61
During succession what changes?
Biotic conditions change as the abiotic conditions change
62
Primary succession ...
happens on bare rock
63
secondary succession occurs...
on land that has been cleared/felled areas
64
What are the abiotic condition like at the start of succession?
harsh
65
What does the pioneer species do to the abiotic conditions?
changes them to make it less hostile so other species can begin to colonise
66
Does the pioneer species survive?
No it will die and be decomposed and add to the soil.
67
What happens to biodiversity as succession continues?
increases
68
The final stage if succession is called?
climax community
69
What sorts of activities prevent succession?
mowing lawn, animals grazing, managed fires
70
give 2 features of a climax community
1. Same species present (over long time) / stable community (over long time); 2. Abiotic factors (more or less) constant (over time); 3. Populations stable (around carrying capacity);
71
How do you use the mark release recapture to determine the population of species A?
1. Capture/collect/sample, mark and release; 2. Leave time before second sampling/collection; 3. (Population =) number in first sample × number in second sample divided by number of marked in second sample/number recaptured
72
Describe MRR
Take a sample of a population Mark them in a way that is not toxic so will not harm them or hinder their chances of survival Release them back into the population Allow time for them to redistribute Collect a second sample Count how many are marked in the second sample (N1 x N2) / N marked in 2nd sample
73
What are some issues if there isn't conservation?
CO2 levels and impact on climate change Reduces Biodiversity Reduces habitats Useful organisms may become extinct (e.g. for medicines)
74
Why should we conserve ecosystems?
Economic – able to keep using the area/tourism Biological – reduces biodiversity, food sources and habitats Ethical – we should prevent damage by humans and help those species effected by us Aesthetic – looks pretty, is a nice place to be
75
Describe Succession
Pioneer species colonises an area with hostile conditions This leads to changes in the abiotic factors The conditions become less hostile Other species are able to colonise the area Conditions continue to change and become less hostile and new organisms outcompete the pioneer species increasing biodiversity Eventually conditions become favourable to a climax community The climax community has stable abiotic factors, stable populations, stable communities

Bio Y13 (29 decks)

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