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Ecology Flashcards

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1
Q

What is ecology?

A

The scientific study of the interactions between organisms and their surroundings.

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2
Q

Define ‘population’ in ecological terms.

A

A group of organisms from the same species, living in the same area at the same time.

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3
Q

What is a community in ecology?

A

Populations of different species living together in the same area at a particular time.

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4
Q

What does ‘habitat’ refer to?

A

A place where an organism lives.

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5
Q

Give an example of a habitat.

A

Habitat of trout is fresh water; habitat of rabbit is a grassland.

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6
Q

What is an ecosystem?

A

A self-sustaining system of organisms interacting with each other and with a physical environment.

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7
Q

What is biodiversity?

A

The amount of variation shown by organisms in an ecosystem.

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8
Q

List the two main components of an ecosystem.

A
  • Biotic components (living)
  • Abiotic components (non-living, physical & chemical)
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9
Q

What are the four main components usually found in an ecosystem?

A
  • Producers
  • Consumers
  • Decomposers
  • The physical environment
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10
Q

What are biotic factors?

A

Living factors that can affect the size and distribution of populations.

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11
Q

How does the availability of food affect population sizes?

A

Areas with rich and diverse food supplies have significantly more animal species.

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12
Q

True or False: Predators prevent prey populations from increasing out of control.

A

True.

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13
Q

What are abiotic factors?

A

Non-living factors that can affect the size and distribution of populations.

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14
Q

How does light intensity affect plant distribution?

A

Some plants require bright light for optimum growth, while others grow better in shade.

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15
Q

Fill in the blank: Biodiversity is mainly due to _______.

A

[Genetic diversity, Species diversity, Ecosystem diversity]

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16
Q

What is species richness?

A

The number of different species present in an ecosystem.

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17
Q

What is evenness in the context of biodiversity?

A

The relative abundance of each species in an ecosystem.

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18
Q

Why is high biodiversity important for an ecosystem?

A

Ecosystems with high biodiversity are often more stable and resilient to ecological disasters.

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19
Q

What is a quadrat?

A

A square frame used to investigate population size or distribution.

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20
Q

What is a transect in ecological studies?

A

A line across a habitat used to record the number of organisms at regular intervals.

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21
Q

What is the purpose of using sampling techniques in ecology?

A

To estimate population sizes or distribution of organisms.

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22
Q

What is population density?

A

The mean number of individual plants per unit area.

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23
Q

What is the mark-recapture method used for?

A

To estimate the population of motile animals.

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24
Q

What are decomposers?

A

Bacteria and fungi that get their energy from feeding off dead and decaying organisms.

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25
What are the different trophic levels in an ecosystem?
* Producers * Primary consumers * Secondary consumers * Tertiary consumers * Decomposers
26
What is a food chain?
The simplest way of showing feeding relationships between a few organisms within an ecosystem.
27
What does a food web represent?
A network of interconnected food chains showing the energy flow through part of an ecosystem.
28
What is a food pyramid?
A diagram that represents the relative amounts of organisms at each trophic level in a food chain.
29
How do changes in one trophic level affect others?
If one trophic level dies out, the trophic level above it decreases in number, while the level below it increases.
30
What does a food chain show?
The food each organism eats
31
What is the source of all energy in a food chain?
Light from the Sun
32
What do the arrows in a food chain represent?
The transfer of energy from one trophic level to the next
33
What are the different stages of a food chain called?
Trophic levels
34
What happens if one trophic level dies out due to disease?
The trophic level above it will decrease in number, and the level below it will increase
35
Changes in a food chain due to disease are usually ______.
Temporary
36
Who gets affected most by poison introduced into a food chain?
The top consumer
37
What is a food web?
A network of interconnected food chains
38
Why are food webs more realistic than food chains?
Animals rarely exist on just one type of food source
39
What does a decrease in the population of slugs lead to in the food web?
Increase in lettuce population and decrease in mistle thrush population
40
Food webs and chains always start with ______.
A green plant
41
How should food webs be drawn?
From the bottom up
42
What do ecological pyramids represent?
The relative amounts of organisms at each trophic level
43
What does a pyramid of numbers show?
How many organisms at each level of a food chain are present in a given area
44
What is an advantage of a pyramid of numbers?
Easy to develop as it is just counting the organisms
45
What is a disadvantage of a pyramid of numbers?
Does not take into consideration the size or mass of the organism
46
What do pyramids of biomass show?
How much mass the creatures at each level would have
47
What is the main disadvantage of a pyramid of biomass?
Accurate mass measurement may damage the ecosystem
48
What does a pyramid of energy transfer show?
The amount of energy at each trophic level
49
What percentage of energy is typically lost between trophic levels?
About 90%
50
Why are food chains limited to few trophic levels?
Due to energy loss at each level
51
What are the two main types of energy in ecosystems?
* Light energy (solar) * Heat energy
52
What is the primary source of energy input in biological systems?
The sun
53
What is the role of microorganisms in nutrient cycling?
They break down complex organic molecules into simpler ones
54
What is the first step in the carbon cycle?
Carbon dioxide is taken out of the atmosphere by plants for photosynthesis
55
What happens to carbon during respiration?
It is returned to the atmosphere as carbon dioxide
56
What is fossilization?
The conversion of carbon in dead organisms into fossil fuels over millions of years
57
What is a major cause of increasing carbon dioxide levels in the atmosphere?
Burning of fossil fuels
58
What is nitrogen's role in biological compounds?
It is present in proteins, amino acids, DNA, ATP, and most vitamins
59
What percentage of the atmosphere is nitrogen gas?
78%
60
How do plants obtain nitrogen?
From soil as ammonium (NH4+) or nitrate (NO3-) ions with the help of bacteria
61
What is the percentage of nitrogen gas in the atmosphere?
78%
62
Why can't animals and plants absorb nitrogen gas (N2) from the air?
N2 gas is very stable and has a triple bond that requires massive amounts of energy to break
63
How do plants obtain nitrogen from the soil?
As NH4+ (ammonium ion) or NO3– (nitrate) ions with the help of bacteria
64
What are the three main types of bacteria involved in the nitrogen cycle?
* Nitrogen fixing bacteria * Nitrifying bacteria * Denitrifying bacteria
65
What do nitrogen fixing bacteria do?
They absorb N2 gas and convert it into ammonium compounds
66
What is the role of nitrifying bacteria?
They convert ammonium ions into nitrate ions which can be used by plants
67
What do denitrifying bacteria convert nitrate ions into?
Atmospheric nitrogen (N2)
68
How do animals obtain nitrogen?
By feeding on plants or other animals to get nitrogen from proteins
69
What happens to nitrogen in animal waste?
It returns to the soil as ammonium compounds
70
What occurs when animals and plants die?
They decay, and their proteins are broken down into ammonium compounds by decomposers
71
What are decomposers in the nitrogen cycle?
Bacteria and fungi that break down dead organic matter
72
Fill in the blank: Lightning can 'fix' N2 gas, turning it into _______.
nitrous oxides like N2O and NO2
73
What is the first stage of the nitrogen cycle?
N-fixation by nitrogen-fixing bacteria
74
What is the process of converting NH4+ into NO3- called?
Nitrification
75
During decomposition, nitrogen in proteins is converted to _______.
NH4+ / NH3
76
What is the last step of the nitrogen cycle?
Denitrification
77
Fill in the blank: As plants grow, they remove nitrates from the soil, and when they die, those nitrates are _______.
returned to the soil
78
What can farmers do to return nitrates to the soil?
* Add animal manure * Grow legume crops * Practice crop rotation
79
True or False: Farmers can reduce the amount of unhelpful bacteria by ploughing and turning over soil.
True
80
Fill in the blank: Green plants absorb nitrogen as _______ from the soil.
NH4+ or NO3-
81
Fill in the blank: Decomposers such as _______ and _______ break down the bodies of dead animals and plants.
bacteria, fungi
82
Fill in the blank: Nitrogen gas from the air can be fixed by _______ fixing bacteria in _______.
nitrogen, root nodules
83
Fill in the blank: Nitrogen from the soil is released back into the atmosphere by _______ bacteria.
denitrifying

Biology (5 decks)

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