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Biology > Ecology > Flashcards

Ecology Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

Define Species

A

A group of organisms that can potentially interbreed to produce fertile, viable offspring

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2
Q

Define Population

A

A group of organisms of the same species that are living in the same area at the same time

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3
Q

Define Community

A

A group of populations living together and interacting with each other within a given area

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4
Q

Defiine Habitta

A

The environment in which a species normally lives, or the location of a living organism

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5
Q

Define Ecosystem

A

A community and its abiotic environment (i.e. habitat)

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6
Q

Define Ecology

A

The study of the relationship between living organisms, or between living organisms and their environment

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7
Q

Define Autotroph

A

Organism that produce their own organic molecules using either light energy or energy derived from the oxidation of chemicals

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8
Q

Define Heterotrophs

A

Organisms which obtain organic molecules from other organisms

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9
Q

Define Detritivores

A

Organisms which ingest organic molecules found in the non-living remnants of organisms (e.g. detritus, humus)

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10
Q

Define Saprotrophs

A

Organism which release digestive enzymes and then absorb the external products of digestion (decomposers)

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11
Q

Define Consumers

A

Organisms which ingest organic molecules from living or recently killed organisms

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12
Q

Define Scavenger

A

A type of consumer that principally feed on dead and decaying carcasses rather than hunting live prey

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13
Q

List 3 Sapotrophs

A

Bacteria
Fungi
Mold

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14
Q

List 3 Detritivores

A

Snail
Earthworm
Crab

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15
Q

Explain how nutrients are recycled

A

Autotrophs obtain inorganic nutrients from the air, water and soil and convert them into organic compounds

Heterotrophs ingest these organic compounds and use them for growth and respiration, releasing inorganic byproducts

When organisms die, saprotrophs decompose the remains and free inorganic materials into the soil

The return of inorganic nutrients to the soil ensures the continual supply of raw materials for the autotrophs

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16
Q

What are the three components necessary for ecosystem sustainability

A

Energy availability – light from the sun provides the initial energy source for almost all communities

Nutrient availability – saprotrophic decomposers ensure the constant recycling of inorganic nutrients within an environment

Recycling of wastes – certain bacteria can detoxify harmful waste byproducts (e.g. denitrifying bacteria such as Nitrosomonas)

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17
Q

How does energy enter a food chain and how does in transfer?

A

Light energy is absorbed by photoautotrophs and is converted into chemical energy via photosynthesis

This light energy is used to make organic compounds (e.g. sugars) from inorganic sources (e.g. CO2)
Heterotrophs ingest these organic compounds in order to derive their chemical energy (ATP)
When organic compounds are broken down via cell respiration, ATP is produced to fuel metabolic processes

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18
Q

Define Trophic level

A

The position an organism occupies within a feeding sequence

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19
Q

Define Food Chain

A

A food chain shows the linear feeding relationships between species in a community

20
Q

How does Energy leave an Ecosystem?

A

Energy stored in organic molecules (e.g. sugars and lipids) can be released by cell respiration to produce ATP

This ATP is then used to fuel metabolic reactions required for growth and homeostasis
A by-product of these chemical reactions is heat (thermal energy), which is released from the organism

21
Q

Why is Energy transfer between trophic levels only 10%

A

Not all energy stored in organic molecules is transferred via heterotrophic feeding – some of the chemical energy is lost by:

Being excreted as part of the organism’s faeces
Remaining unconsumed as the uneaten portions of the food

22
Q

Define Biomass

A

The total mass of a group of organisms

23
Q

List the 4 Spheres on Earth

A

The four spheres are the atmosphere (air), lithosphere (ground), hydrosphere (water / oceans) and biosphere (living things)

24
Q

What is Carbon stored in?

A

Atmospheric gases – mainly carbon dioxide (CO2), but also methane (CH4)
Oceanic carbonates – including bicarbonates dissolved in the water and calcium carbonate in corals and shells
As organic materials – including the carbohydrates, lipids and proteins found in all living things
As non-living remains – such as detritus and fossil fuels

25
Q

What are the immediate processes

Fuel–>Car–> Atmosphere

A

Extraction

Pollution

26
Q

How does the ocean pH decrease?

A

Carbon dioxide dissolves in water and some of it will remain as a dissolved gas, however the remainder will combine with water to form carbonic acid (CO2 + H2O ⇄ H2CO3)

Carbonic acid will then dissociate to form hydrogen carbonate ions (H2CO3 ⇄ HCO3– + H+)
This conversion also releases hydrogen ions (H+), which is why pH changes when CO2 is dissolved in water (> acidic)

27
Q

How is limestone developed?

A

When the hydrogen carbonate ions come into contact with the rocks and sediments on the ocean floor, they acquire metal ions

This commonly results in the formation of calcium carbonate and the subsequent development of limestone

28
Q

How do organisms utilize carbonate ions?

A

Living animals may also combine the hydrogen carbonate ions with calcium to form calcium carbonate

This calcium carbonate forms the hardened exoskeleton of coral, as well as forming the main component of mollusca shells
When the organism dies and settles to the sea floor, these hard components may become fossilized in the limestone

29
Q

Define Methanogens

A

Archaean microorganisms that produce methane (CH4) as a metabolic by-product in anaerobic conditions

30
Q

How do Methanogens produce methane from the by-products of anaerobic digestion, principally acetic acid and carbon dioxide:

A

Acetic acid → Methane and Carbon Dioxide (CH3COO– + H+ → CH4 + CO2)
Carbon Dioxide and Hydrogen → Methane and Water (CO2 + 4 H2 → CH4 + 2 H2O)

31
Q

How does methane accumulate under the ground?

A

When organic matter is buried in anoxic conditions (e.g. sea beds), deposits of methane (natural gas) may form underground

32
Q

Why is methane in low abundance in the atmosphere?

A

Methane will be naturally oxidised to form carbon dioxide and water (CH4 + 2 O2 → CO2 + 2 H2O)

33
Q

How is peat formed?

A

Anaerobic respiration by organisms in water logged regions produces organic acids (e.g. acetate), resulting in acidic conditions

Saprotrophic bacteria and fungi cannot function effectively in anaerobic / acidic conditions, preventing decomposition

Since the organic matter is not fully decomposed in waterlogged soils, carbon-rich molecules remain in the soil and form peat

34
Q

How is coal formed?

A

When deposits of peat are compressed under sediments, the heat and pressure force out impurities and remove moisture

The remaining material has a high carbon concentration and undergoes a chemical transformation to produce coal

35
Q

How is Oil/Natural gas formed?

A

Oil (i.e. petroleum) and natural gas form as the result of the decay of marine organisms on the ocean floor

Sediments (e.g. clay and mud) are deposited on top of the organic matter, creating anoxic conditions that prevent decomposition
As a result of the burial and compaction, the organic material becomes heated and hydrocarbons are formed
The hydrocarbons form oil and gas, which are forced out of the source rock and accumulate in porous rocks (e.g. sandstone)

36
Q

Why are fossil fuels non-renawable?

A

The formation of fossil fuels (coal, oil and gas) takes place over millions of years, making them a non-renewable energy source

37
Q

Define Carbon flux

A

Carbon fluxes describe the rate of exchange of carbon between the various carbon sinks / reservoir

38
Q

Which Natural Events increase CO2?

A

Forest fires can release high levels of carbon dioxide when plants burn (loss of trees also reduces photosynthetic carbon uptake)
Volcanic eruptions can release carbon compounds from the Earth’s crust into the atmosphere

39
Q

How is human Activity increasing CO2 concentrations?

A

Clearing of trees for agricultural purposes (deforestation) will reduce the removal of atmospheric CO2 via photosynthesis

Increased numbers of ruminant livestock (e.g. cows) will produce higher levels of methane

The burning of fossil fuels will release carbon dioxide into the atmosphere

40
Q

Which gases cause the green house effect?

A

Most abundant: Water and CO2

Less abundant: Methane and NOx

41
Q

Which factors decided on what impact a substance has on the greenhouse effect?

A

Gases that have a greater capacity to absorb long-wave radiation will have a greater warming impact (per molecule)

The greater the concentration of a gas, the greater its warming impact will be within the atmosphere
The concentration of a gas will be determined by both its rate of release and persistence within the atmosphere

42
Q

Why is the green house effect nessecary?

A

It ensures the Earth maintains the moderate temperatures needed by organisms to maintain life processes (homeostasis)
Without a greenhouse effect, Earth’s temperatures would drop significantly at night in the absence of direct sunlight

43
Q

How does warming of the earth occur via the green house effect?

A

Incoming radiation from the sun is shorter wave radiation (ultraviolet radiation and the visible spectrum)

The surface of the Earth absorbs short wave radiation and re-emits it at a longer wavelength (i.e. infra-red / heat)

Greenhouse gases absorb and re-radiate this longer wave radiation and hence retain the heat within the atmosphere

44
Q

What may be the effect of increased global temperature?

A

More frequent extreme weather conditions (e.g. heat waves, cyclones, more powerful tropical storms, etc.)

Some areas to become more drought affected, while other areas become more prone to periods of heavy rainfall

Changes to circulating ocean currents – which may cause longer El Nino (warming) and La Nina (cooling) events

45
Q

When did carbon dioxide levels begin to increase?

A

The industrial revolution introduced new manufacturing processes which significantly increased mankind’s use of fossil fuels

The burning of fossil fuels releases carbon dioxide as a by-product, leading to a steady increase in its atmospheric concentration

46
Q

How does ocean acidification effect corals? 8 marks

A

Carbon dioxide will combine with water to form carbonic acid, which dissociates into hydrogen ions and hydrogen carbonate
H+ ions will lower the ocean pH (acidification) and will also combine with free carbonate ions to form more hydrogen carbonate
With less free carbonate ions in the water, marine organisms are less able to produce calcium carbonate (via calcification)
Calcium carbonate is used to form the hard exoskeleton of coral and is also present in the shells of certain molluscs
Hence increasing concentrations of dissolved carbon dioxide threatens the viability of coral reefs and certain molluscs

Biology (13 decks)

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