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IBDP Biology SL/HL > (SL) Unit 4: Ecology; Topic 4.1 Species, Communities, and Ecosystems > Flashcards

(SL) Unit 4: Ecology; Topic 4.1 Species, Communities, and Ecosystems Flashcards

Flashcard Main Resource: https://ib.bioninja.com.au/standard-level/topic-4-ecology/41-species-communities-and/

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1
Q

A species is…

A

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

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2
Q

Members of a single species are unable to…

A

produce fertile, viable offspring with members from a different species

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3
Q

When two different species do produce offspring by cross-breeding…

A

these hybrids are reproductively sterile (e.g. liger, mule)

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4
Q

A population is…

A

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

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5
Q

Organisms that live in different regions (i.e. different populations) are…

A

reproductively isolated and unlikely to interbreed, however are classified as the same species if interbreeding is functionally possible

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6
Q

A Community is…

A

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

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7
Q

A habitat is..

A

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

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8
Q

An ecosystem is…

A

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

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9
Q

What is an abiotic environment?

A

a non-living part of an ecosystem that shapes its environment

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10
Q

Ecology is…

A

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

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11
Q

What are the 2 methods of nutrition for species?

A

autotrophic or heterotrophic

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12
Q

What is an autotrophic mode of nutrition?

A

Autotrophic nutrition is the type of nutrition where organisms synthesize their own food.

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13
Q

Because autotrophs synthesise their own organic molecules they are commonly referred to as…

A

producers

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14
Q

Where do autotrophs synthesize its own organic molecules from?

A

simple inorganic substances (e.g. CO2, nitrates)

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15
Q

Energy for the synthesis process in autotrophs is derived from…

A

sunlight (photosynthesis) or via the oxidation of inorganic molecules (chemosynthesis)

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16
Q

What is a heterotrophic mode of nutrition?

A

Heterotrophic nutrition is the mode of nutrition where the organism is unable to prepare its food and hence, depends upon plants or other organisms for nutrition.

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17
Q

Heterotrophs obtain organic molecules from…

A

other organisms (either living / recently killed or their non-living remains and detritus)

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18
Q

Because heterotrophs cannot produce their own organic molecules and obtain them from other sources, they are called…

A

Consumers

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19
Q

What is a mixotrophic mode of nutrition?

A

Mixotrophy is the mode of nutrition whereby an organism has the ability to gain carbon and/or nutrients by using two functionally different processes: photosynthesis and the uptake from organic matter. (Autotrophs and Heterotrophs)

for example; Euglena gracilis possess chlorophyll for photosynthesis (autotrophic) but may also feed on detritus (heterotrophic)

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20
Q

Certain unicellular organisms may on occasion use both forms of nutrition, depending on…

A

resource availability

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21
Q

Autotrophs produce their own organic molecules using…

A

either light energy or energy derived from the oxidation of chemicals

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22
Q

Autotrophs obtain the simple inorganic substances required for the process of obtaining their own organic molecules from…

A

the abiotic environment

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23
Q

the nutrients collected from the abiotic environment for the process include…

A

carbon, nitrogen, hydrogen, oxygen and phosphorus

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24
Q

where are those nutrients are obtained from?

A

the air, water and soil

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25
Q

Heterotrophs also may obtain some simple inorganic substances from the environment but principally obtain their carbon and nitrogen from the organic molecules produced by…

A

autotrophs

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26
Q

Heterotrophs obtain organic molecules from…

A

other organisms via one of three methods

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27
Q

What are the 3 methods of Heterotrophs obtaining organic molecules?

A

Consumers
Detritivores
Saprotrophs

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28
Q

How do consumers obtain organic molecules?

A

they ingest organic molecules from living or recently killed organisms

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29
Q

How do detritivores obtain organic molecules?

A

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

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30
Q

How do saprotrophs obtain organic molecules?

A

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

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31
Q

What are consumers?

A

they are heterotrophs that feed on living organisms by ingestion

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32
Q

What are examples of consumers?

A

Herbivores , Carnivores and Omnivores

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33
Q

What are herbivores?

A

Herbivores are consumers that feed principally on plant matter (e.g. cows, sheep, rabbits)

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34
Q

What are carnivores?

A

Carnivores are consumers that feed principally on animal matter (e.g. crocodiles, wolves, tigers)

35
Q

What are omnivores?

A

Omnivores are consumers that have a principle diet composed of both plant and animal matter (e.g. pandas, humans)

36
Q

What are scavengers?

A

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

37
Q

What are some examples of scavengers?

A

Hyenas, vultures, and carrion birds (such as crows))

38
Q

What are detritivores?

A

Detritivores are a type of heterotroph that obtains nutrients from non-living organic sources, such as detritus and humus

39
Q

What is detritus?

A

Detritus is dead, particulate organic matter – such as decaying organic material and fecal matter

40
Q

What is humus?

A

Humus is the term given specifically to the decaying leaf litter intermixed within the topsoil

41
Q

What are some examples of detritivores?

A

Dung beetles, earthworms, woodlice, snails and crabs

42
Q

What are saprotrophs?

A

Saprotrophs are heterotrophs that obtain organic nutrients from dead organisms by external digestion

43
Q

Saprotrophs live on (or in)…

A

non-living organic matter, they secrete digestive enzymes into it and absorb the products of digestion

44
Q

Unlike other types of heterotrophs, saprotrophs do not ingest food but use … to facilitate external digestion

A

enzymatic secretion

45
Q

What is enzymatic secretion?

A

it is digestive enzymes secreted by different exocrine glands

46
Q

Because saprotrophs facilitate the breakdown of dead organic material, they are commonly referred to as…

A

decomposers

47
Q

What are examples of saprotrophs?

A

bacteria and fungi

48
Q

The supply of inorganic nutrients is maintained by…

A

nutrient cycling

49
Q

Nutrients refer to the material required by an organism, and include elements such as…

A

carbon, nitrogen and phosphorus

50
Q

The supply of inorganic nutrients on Earth is finit, this means that?

A

new elements cannot simply be created and so are in limited supply, hence chemical elements are constantly recycled after they are used

51
Q

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

A

organic compounds

52
Q

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

A

inorganic byproducts

53
Q

When organisms die, saprotrophs…

A

decompose the remains and free inorganic materials into the soil

54
Q

The return of inorganic nutrients to the soil ensures what for autotrophs?

A

the continual supply of raw materials

55
Q

Ecosystems have the potential to be what over long periods of time?

A

sustainable

56
Q

Ecosystems describe the interaction between…

A

biotic components (i.e. communities) and abiotic components (i.e. habitat)

57
Q

What are the three main components required for sustainability in an ecosystem?

A

Energy availability, Nutrient availability, and Recycling of wastes

58
Q

How is energy availability a main component for sustainability in an ecosystem?

A

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

59
Q

How is nutrient availability a main component for sustainability in an ecosystem?

A

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

60
Q

How is recycling of waste a main component of sustainability in an ecosystem?

A

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

61
Q

What is a mesocosm?

A

Mesocosms are enclosed environments that allow a small part of a natural environment to be observed under controlled conditions

62
Q

What is a terrarium?

A

A terrarium is a small transparent container (e.g. glass or plastic) in which selected plants (or animals) are kept and observed

63
Q

What are the 3 main steps to making a Self-Sustaining Terrarium?

A

Building a verdant foundation, Selecting the right plants
, and Maintaining appropriate conditions

64
Q

How do you build a verdant foundation?

A

Add a bottom layer of pebbles, gravel or sand – this layer exists for drainage (smaller vessels require thinner rock layers)
Add a second thin layer of activated charcoal – this will prevent mold and help to aerate the soil
Spread a thin cover of sphagnum moss (or use an organic coffee filter) to create a barrier between the lower layers and soil
The final layer is the pre-moistened growing medium (i.e. potting mix)

65
Q

How do you select the right plants?

A

Ideally, choose plants that are both slow growing and thrive in a bit of humidity (e.g. most ferns, club moss, etc.)
Inspect the plant thoroughly for any signs of disease or insects before introducing to the terrarium

66
Q

How do you maintain appropriate conditions?

A

Ensure the terrarium is placed in a location that provides a continuous source of light
Locate the terrarium in a place that does not experience fluctuating temperature conditions (i.e. avoid direct sunlight)
Do not initially over-water the plants – once the right humidity is established, a terrarium can go months without watering
Occasional pruning may be required – however, as level of soil nutrients decrease, plant growth should slow down

67
Q

What is the chi-square test?

A

A chi-square test is a statistical test used to compare observed results with expected results.

68
Q

What is the purpose of the chi-squared test?

A

The purpose of this test is to determine if a difference between observed data and expected data is due to chance, or if it is due to a relationship between the variables you are studying.

69
Q

The presence of two species within a given environment will be dependent upon…

A

potential interactions between them

70
Q

If two species are typically found within the same habitat, they show a…

A

positive association

71
Q

Species that show a positive association include those that exhibit…

A

predator-prey or symbiotic relationships

72
Q

If two species tend not to occur within the same habitat, they show a…

A

negative association

73
Q

Species will typically show a negative association if there is…

A

competition for the same resources

74
Q

What is competitive exclusion?

A

it is where one species may utilise the resources more efficiently, precluding survival of the other species

75
Q

What is resource partitioning?

A

it is where both species may alter their use of the environment to avoid direct competition

76
Q

If two species do not interact…

A

there will be no association between them and their distribution will be independent of one another

77
Q

The presence of two species within a given environment can be determined using…

A

quadrat sampling

78
Q

How do you establish population densities?

A

By using a quadrat is which is a rectangular frame of known dimensions

79
Q

Using a quadrant how is the population density established?

A
  • Quadrats are placed inside a defined area in either a random arrangement or according to a design (e.g. belted transect)
  • The number of individuals of a given species is either counted or estimated via percentage coverage

-The sampling process is repeated many times in order to gain a representative data set

80
Q

Is quadrat sampling is an effective method for counting motile organisms?

A

No

81
Q

What is quadrant sampling then used for?

A

it is used for counting plants and sessile animals

82
Q

In each quadrat what is identified?

A

the presence or absence of each species

83
Q

A chi-squared test can be applied to data generated from quadrat sampling to determine…

A

if there is a statistically significant association between the distribution of two species

84
Q

What are the 5 steps to complete a chi-squared?

A

1) Identify hypotheses (null versus alternative)
2) Construct a table of frequencies (observed versus expected)
3) Apply the chi-squared formula
4) Determine the degree of freedom (df)
5) Identify the p value (should be <0.05)

IBDP Biology SL/HL (3 decks)

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