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Principles of ecology! Flashcards

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1
Q

describe the relationship between acacia trees and crematogaster (acrobat ant)

A

symbiotic/mutualistic relationship where tree provides a home for the ants (in the bulbous thorns) and the ants protect the tree against defoliation from elephants.

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2
Q

what would the impact on the savannah be if crematogaster were replaced by invasive pheidole (big headed ants).

A

crematogaster protect acacia from defoliation by biting and stinging elephants but pheidole dont do this and so the trees are defoliated and the savannah can be described as going from closed to open.

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3
Q

how would the pheidole ants also change the diet of lions on the savannah

A

if the savannah becomes more open and visibility increases then zebra, which are the lions usual diet, will be able to see the lions approach and will avoid predation. Therefore, the lions are likely to hunt buffalo instead of zebra.

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4
Q

what is the definition of ecology

A

the study of the interactions (biotic and abiotic) that determine the distribution and abundance of organisms.

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5
Q

what are the ten principles of ecology

A
  • the sun is the ultimate energy source
  • ecology is hierarchical
  • organisms are chemical machines
  • nutrients cycle, energy flows
  • populations change
  • communities change
  • interactions alter abundance
  • ecosystems are webs of interactions
  • humans disproportionately impact ecosystems
  • ecosystems are essential for human civilisation
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6
Q

describe the hierarchy of ecology

A

organism
population
species
community
ecosystem
biome
biosphere

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7
Q

define population

A

a group of organisms that interbreed

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8
Q

define community

A

collections of species that interact and occur at the same time and location

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9
Q

define biome

A

a geographical region with similar ecosystem types and climatic conditions

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10
Q

describe the linnean classification system

A

domain Dear
kingdom Kevin
phylum Please
class Come
order Over
family For
genus Gay
species Sex

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11
Q

why is an understanding of evolutionary history important for interpreting ecological patterns

A

species with more recent common ancestry are likely to share more similar characteristics and therefore they may respond to abiotic and biotic factors in a similar way.

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12
Q

which types of electromagnetic radiation are most significant to biology

A

infra red
visible light
ultra violet light

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13
Q

what important process is light used for

A

photosynthesis

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14
Q

why is only 4.6% of total sunlight used in photosynthesis to fuel life?

A

51% is outside of the photosynthetically active range
49% is reflected away from the leaves
26% is lost due to the cost of photosynthesis
so only 4.6% fuels life

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15
Q

describe the trophic levels of an energy flow diagram

A

sun-> autotrophs/primary producers -> heterotrophs/primary consumers ->
heterotrophs/secondary consumers

saprotrophs consume the dead material of both autotrophs and heterotrophs

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16
Q

why isn’t the suns output distributed evenly over the earths surface?

A

the tilt of the earth leads to seasons and the curvature of the earth leads to more intense sunlight falling at the equator compared to the poles.

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17
Q

what is GPP and NPP

A

GPP - Gross Primary Productivity
this is the amount of chemical energy expressed as carbon biomass produced by autotrophs
NPP - Net Primary Productivity
this is the carbon biomass available to consumers after energy is lost through respiration
NPP = GPP - respiration

Respiration R = the amount of energy required to maintain the autotroph during the period over which photosynthesis is measured.
As predicted, higher levels of NPP are seen in the tropics

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18
Q

what is the relationship between primary productivity and species richness

A

as primary productivity increases, the species richness increases because there is more energy in the system to support more organisms and species.

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19
Q

what are the organisms called who use light as an energy source

A

phototrophs

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20
Q

what are the organisms called that do not use light as a source of energy

A

chemotrophs

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21
Q

what are the two main roles of organisms

A

to pass on their genes and to be part of the food web.

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22
Q

what elements are useful solvents

A

hydrogen and oxygen (H2O)

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23
Q

what elements are useful for energy storage

A

phosphorous, carbon, hydrogen, oxygen (ATP)

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24
Q

what elements are useful for structural tissues

A

nitrogen, carbon, calcium, phosphorous, sulphur
used for musculature, bones and plant support tissues

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25
what elements are useful gradient generators
sodium, potassium, chlorine, calcium, hydrogen. drives the production of ATP and are involved in action potentials allows nutrients to be concentrated inside the cell and waste products to be expelled.
26
what elements are useful for catalysis
eg. zinc, magnesium, copper, manganese, cobalt, fluorine, chlorine, iodine, selenium, molybdenum, chromium
27
what elements are useful for transporters
iron (haem groups in mammal haemoglobin), copper (in the pigment in insect haemolymph)
28
what are the main elements found in organic matter
carbon, hydrogen, oxygen, nitrogen
29
what might determine the types of elements used by an organism
it is more likely to be used if it is found in higher concentrations in their environment
30
what element is used by Melissotaurus ants and for what purpose
zinc in the mandibles for cutting through lignin in bark.
31
what are the laws of conservation of energy and mass and the law of motion that organisms must obey
energy and mass cannot be created or destroyed only converted between different forms. energy must be exerted to move and to stop moving.
32
what is secondary productivity
the carbon biomass produced by heterotrophs.
33
what is a pyramid of biomass
indicates primary and secondary productivity (biomass produced) as you go up the trophic levels.
34
why is energy lost at each trophic level
not all of the organism is consumed or digested, some is excreted. energy is lost through respiration which is used for heat generation, movement and metabolism and is not converted to biomass. energy can be exported out of the ecosystem. energy can be unavailable if it is stored as fossil fuels.
35
describe the nitrogen cycle
N2 nitrogen fixation to form NH3 nitrification to form NO3^- and NO2^- denitrification to form N2 cycles between organic and inorganic form
36
describe the carbon cycle
CO2 fixed by photosynthesis into organic matter passed through food chain released in respiration as CO2
37
what can populations be described as
increasing, stable, decreasing
38
why is it important to monitor populations
to identify if there needs to be conservation implemented and to monitor if conservation is having an impact.
39
what is the most important thing to understand when implementing conservation methods
the factors that have led to the decline in the population so that the methods employed will be appropriate and effective
40
what is the equation to describe the rate of population change
(change in population size/change in time)= births + net immigration - deaths immigration can be positive or negative depending on whether it is movement in (+) or out (-).
41
how can population size be measured
a consensus is most accurate but is time consuming and difficult to know if every organism has been counted (depending on how easily they can be observed). an estimate is used instead using methods such as capture mark recapture.
41
what are the challenges to measuring the rate of change in population size
-measuring population size -defining birth -counting deaths -measuring immigration -defining boundaries for a population
42
what is the equation used for capture mark recapture
(no. of recaptured/no. in second sample)= (no. marked/ total no. in first and second sample)
43
how do you calculate population density
no. per unit area then extrapolate over the whole unit area. have to sample a large enough area to be representative of whole area
44
what should be considered when marking organisms in capture mark recapture
that the mark does not influence the probability of survival as there needs to be the same probability of recapturing a marked or non-marked organism.
45
why might birth be difficult to define
with plants is this the seed or when the seed had germinated or once the plant has reached a certain height for animals with different life stages and environmental niches such as butterflies when would the point of the birth be
46
why are deaths hard to count
because bodies decompose really quickly and so are not visible to count
47
how can immigration be monitored
looking for differences in morphology or genetics. comparisons can be made with other populations to see where they might have come from
48
what drives birth and death rates
intraspecific competition which is density dependent (higher density=higher competition=higher deaths than births). (lower density=lower competition=higher birth than death rate).
49
what is the carrying capacity
the population density where the population remains stable/ in equilibrium (births=deaths)
50
what is the equation for the rate of change in species number within a community?
(change in species number/change in time)= speciation + net dispersal - extinction net dispersal can be positive (in) or negative (out) extinction can include loss from that area which is called extirpation.
51
why might a species enter or leave a community?
a species will enter if a niche becomes available that they can fill and they can remain in the community as long as that niche remains
52
what is a niche
a niche is the biotic and abiotic factors that an organism requires for survival. This is multidimensional as there are many factors to consider that must overlap to create a suitable environment.
53
what are the main interactions between organisms
mutualistic (+/+) Parasitic (+/-) commensal (+/0) Competing (-/-)
54
What is a food web?
A food web describes the variety of interactions (positive or negative) that occur amongst all the species that exist within a system
55
describe the relationship between otters, kelp, sea urchins and abalone.
otters eat sea urchins and abalone. sea urchins eat the kelp. kelp provide habitat for abalone.
56
what is the effect on the abalone when the otter numbers increase
the abalone number increases which seems counterintuitive but makes sense because the more otters there are, the less sea urchins there are and therefore the more kelp there is which is providing habitat for the abalone. this outweighs the effect of the otters eating the abalone
57
what is the effect of human presence in Zion national park (US)
if human visitors increase in one area, cougars move away from the area which leads the number of deer to increase in the area to avoid predation. Then due to increased grazing from deer there is less cottonwood trees, the roots of which are important for the structural integrity of river banks. therefore, where there is a larger human presence, the rivers are wider and shallower than where there is less of a human presence.
58
how have humans been able to exceed their carrying capacity
by technological innovation (industrial revolution), domestication of plants and animals, establishment of agriculture
59
compared to wild animals how many humans and livestock are there
there are more humans than wild birds and mammals combined. there are more livestock than humans
60
which eon are we currently in
anthropocene
61
how are different eons defined
by whether the passage of time has geological evidence in rock layers.
62
what are the reasons for habitat loss
agricultural expansion, urbanisation, forestry
63
what are the effects of humans on ecosystems
habitat loss climate change leading to northward migration invasive species pollution decline in biodiversity
64
what are the ecosystem services
cultural- ecotourism, spiritual practice, aesthetics provisioning-food, fuel, building materials, biochemicals and medicines regulating- climate, pollination, erosion control supporting- soil formation, primary production, nutrient cycling
65
What can trophic cascades illustrate?
Trophic cascades emphasise the indirect effects on a given species abundance that can occur due to activity in a completely different part of the food chain or web
66
Give an example of how a trophic cascade can affect the layout of the landscape
Cougars hunt and eat deer. The deer, if their abundances are too high, prevent the establishment of cottonwood trees. The cottonwood trees are crucial in preventing streambanks from eroding as their root network ties together the soil in these places. Consequently, in areas with low cougar numbers the amount of river banks in a state of erosion is much higher and the streams are much wider and shallower

Organisms and environment (17 decks)

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