Principles of Ecology Flashcards
1
Q
Ecology
A
the study of the relationships between living organisms and their environment
2
Q
Habitat
A
the place where an organism or group of organisms live
3
Q
community
A
all the organisms in an ecosystem or habitat
4
Q
population
A
all the organisms of the same species living in an area
5
Q
ecosystem
A
organisms and their (non-living) environment together
6
Q
biosphere
A
the part of the earth where life can exist
7
Q
niche
A
the functional role of an organism in an ecosystem (or food chain) e.g green plants are producers
8
Q
main feature of a desert ecosystem
A
low rainfall e.g sahara
9
Q
main feature of a tropical rainforest ecosystem
A
high rainfall and warm summers e.g West Africa and Brazil
10
Q
main feature of a temperate deciduous forest ecosystem
A
high rainfall and warm summers e.g eastern USA and western Europe
11
Q
main feature of marine ecosystem
A
salt water e.g oceans and sea shorts
12
Q
2 types of organisms in an ecosystem
A
producers
consumers
13
Q
producers
A
autotrophs - organisms that make their own food using simple molecules (mainly green plants)
14
Q
consumers
A
heterotrophs - organisms that cannot make their own food and take in and use food made by others
15
Q
3 types of consumers
A
primary consumers
secondary consumers
tertiary consumers
16
Q
primary consumers
A
herbivores - organisms that eat plants, e.g rabbits eat grass, bees eat pollen
17
Q
secondary consumers
A
carnivores - organisms that eat animals (the primary consumers) e.g foxes eat rabbits, spiders eat flies
18
Q
tertiary consumers
A
top carnivores - organisms that eat secondary consumers e.g thrushes eat spiders
19
Q
omnivores
A
organisms that eat both plant and animal material e.g hedgehog, blackbird
20
Q
decomposers
A
e.g saprophytic bacteria and fungi, these organisms live and feed on dead organisms
21
Q
ecosystems can only flow if
A
energy is constantly taken in from an external force
22
Q
primary source of energy for our planet
A
the sun and its ecosystems
23
Q
what do feeding relationships in food chains and food webs show?
A
the pathway of energy flow in an ecosystem
24
Q
food chain
A
a pathway along which food is passed from one species to another
25
a grazing food chain
a food chain that begins with a plant (a producer)
26
trophic level
each feeding stage
27
what is passed on from one trophic level to the next
a small amount of energy
28
most energy is lost as
heat in respiration
29
why are food chains generally short?
because of the loss of energy
30
food web
a number of interconnected food chains
31
pyramid of number shows
the number of organisms at each trophic level in a food chain
32
as you go up the pyramid 2
size of organism increases
| number of organisms decreased
33
2 limitations of the pyramid of numbers
number of organisms may be difficult to count accurately
| does not take size of organism into account
34
heat energy cannot be recycled and as a result
energy flows through ecosystems in one direction only
35
what can be continuously recycled and reused?
biomolecule such as carbon and nitrogen
36
biochemical cycles
biomolecules released from the bodies of dead organisms and taken in and reused by living organisms in these cycles
37
how much of living matter is made up by carbon?
about 18%
38
major source of carbon for living organisms
CO2
39
4 main events in the carbon cycle
photosynthesis
respiration
decay
combustion
40
photosynthesis
green plants take in CO2 and use it in photosynthesis to make carbohydrate, animals get carbon by eating plants and other organisms
41
respiration
all living organisms breakdown carbon compounds and release CO2
42
decay
microorganisms (decomposers) break down dead organisms and release CO2
43
combustion
burning of fossil fuels releases CO2
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2 reasons why CO2 in atmosphere is increasing
increased combustion of fossil fuel
| increased deforestation
45
2 effects of global warming
rising sea levels
| rising deforestation
46
4 molecules with nitrogen
protein, DNA, RNA, ATP
47
composition of air - nitrogen
80%
48
plants take in nitrogen as
nitrate (NO3) dissolved in soil water
49
what does the nitrogen cycle ensure?
that nitrogen is available for use by living organisms
50
continued supply of nitrogen involves 2
nitrogen fixation
| recycling of nitrogen
51
nitrogen fixation
nitrogen gas converted to nitrate and ammonia
52
what does nitrogen fixation
some bacteria e.g rhizobium
53
where do rhizobium live?
in nodules or swellings on the roots of legumes e.g clover, soya, peas
54
describe the symbiosis of nitrogen - fixing bacteria
bacteria take in N2 gas and convert it to nitrate which is given to the plant the plant in return gives food and shelter to the bacteria
55
recycling of nitrogen
nitrates and nitrogen gas are reformed from protein in dead organisms by different bacteria in the soil
56
3 types of bacteria in the soil
saprophytes
nitrifying bacteria
denitrifying bacteria
57
saprophytes recylce
protein
| ammonia
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nitrifying bacteria recycle
ammonia
| nitrite nitrite nitrite
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denitrifying bacteria recycle
nitrate
| nitrogen (N2)
60
2 types of environmental factors affecting organisms
abiotic (non-living) and biotic (living)
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abiotic factors
the non-living features of the environment that affect living organisms
62
2 types of abiotic factors
edaphic
| climatic
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edaphic factors
factors relating to the soil
64
main edaphic factors
```
particle size
humus content
water content
air content
mineral content
pH
```
65
particle size of sandy soil
contains large sand particles - tend to lose water and minerals and relatively infertile
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particle size of clay soil
contains a large amount of small clay particles - retain water and minerals but tend to waterlog and become infertile
67
particle size of loam soil
contains a mixture of sand and clay particles and is the most fertile soil
68
humus
decaying organic matter in the soil that provides food, retains water and minerals and helps bind soil particles together
69
where do earthworms thrive?
in humus rich soil
70
why is water content significant ?
water is needed for photosynthesis, transpiration and general metabolism. minerals enter plats dissolved in water
71
air content
this provides oxygen for plant root, microorganism and animal respiration, plants don't grow well in oxygen-poor soils e.g waterlogged soil
72
mineral content
minerals like magnesium and nitrogen are needed by plants for healthy growth, lack of magnesium causes yellowing of leaves or chlorosis, lack of nitrogen causes stunted growth
73
pH
plants and animals have certain pH requirements e.g bog mosses and heathers need an acid soil
most plants prefer neutral soil
74
the major climactic factors that affect the distribution and behaviour of organisms
```
temperature
rainfall
light intensity
humidity
day length
```
75
temperature
affects the rate of metabolism in living this. higher temperatures cause rapid plant growth in summers
lower temperatures cause the hibernation of some animals during the winter and the death of others
76
rainfall
provides water - essential for life and determines the distribution of terrestrial life. only plants such as cacti can live in places with low rainfall such as deserts. plants in tropical rain forests need a lot of rain
77
light intensity
affects the rate of photosynthesis. woodland plants e.g bluebell, flower in the spring before the leaves come on the trees and block the light
plankton in the sea grow best in the upper layers due to the higher light intensity
78
humidity
water vapour content of air
effect on transpiration rate of plants
high humidity in the air reduces transpiration
woodlice only live in humid conditions under rooting leaves
79
day length
this affects flowering and germination in plants, hibernation and reproduction in animals
80
5 abiotic factors that affect aquatic environments
```
light
currents
wave action
salt content
oxygen concentration
```
81
abiotic factors that affect aquatic environments
| light
water stops light penetrating
plants confined to upper layers
rock seashore - Fucus can photosynthesis underwater because it has fucoxanthin
82
fucoxanthin
a pigment that traps light that filters through the water
83
other thing that fucus also has
air bladders that keep the plant upright in the water close to the light
84
abiotic factors that affect aquatic environments
| currents
moving water will carry away any organisms not attached
| fucus has a holdfast to attach it to rocks
85
abiotic factors that affect aquatic environments
| wave action
this can cause physical damage to organisms, seaweeds living on a rocky seashore have flexible stalk that can withstand wave action
86
abiotic factors that affect aquatic environments
| salt content
this causes problems relating to the movement of water in and out of organisms. in rock pools, some seaweeds and marine snails only survive due to the effect of rainwater
87
abiotic factors that affect aquatic environments
| oxygen concentration
water has a lower concentration of oxygen than air. animals and plants living in water must have a large surface area for gaseous exchange
88
what are biotic factors
the influence of living organisms on each other
89
3 biotic factors
competition
predation
symbiosis
90
competition
the struggle between two or more organisms for a resource that is in short supply
91
what do organisms compete for?
food, space, water, light, minerals, shelter and mates
92
what is competition significant in?
controlling population size
93
2 main types of competition
contest competition
| scramble competition
94
contest competition
involves active physical contest, one wins it all, e.g birds compete for territory
95
scramble competition
struggle for limited resource and resource is shared by all e.g rabbits in a field sharing available plants
96
3 animals in grassland
spiders
snails
earthworms
97
adaption of spiders
carnivores with strong mouthparts to crush their prey
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adaption of snails
herbivores with a shell for protection against predators and drying out
99
adaption of earthworms
live in damp soil, feeding on dead organic matter
100
3 plants in grassland
dandelion
daisy
clover
101
adaption of dandelion
leaves spread out close to ground, blocking the light and prevent grass from growing. seeds are dispersed by wind
102
adaption of daisy
leaves spread out close to ground. new plants form from stem of parent and prevent grass from growing
103
adaption of clover
can grow in nitrogen-poor soil
104
predator
an organism that kills and eats another living organism
105
prey
an organism that is killed and eaten
106
example of predation
foxes prey on rabbits
107
where is predation important
in population control
108
what is interrelated in predation
numbers of predators and prey
109
increase in prey
increase in predators
110
increase in predators
decrease in prey
111
3 predators
foxes
spiders
hawks
112
adaption of foxes
sharp pointed teeth and very good eyesight, run very fast
113
adaption of spiders
strong mouthparts and release venom, use webs
114
adaption of hawks
sharp talons and beaks and very good eyesight
115
3 prey
greenfly
mice
snails
116
adaption of greenfly
green bodies for camouflage
117
adaption of mice
have large eyes and sensitive ears - furs blends into surroundings and they run and hide from predators
118
adaption of snails
shells for protection
119
symbiosis
where two organisms of different species live together and at least one benefits
120
organisms involved in symbiosis
symbionts
121
3 types of symbiosis
mutualism
parasitism
commensalism
122
mutualism
two organisms of different species live together and both benefit
123
2 examples of mutualism
bacteria in large intestine of humans produce vitamin K
| nitrogen-fixing bacteria in root nodules in clover plants
124
parasitism
two organisms of different species live together; one called the parasite loves in or on the other (host), feeds on it and causes harm
125
4 examples of parasitism
fleas on skin of cats and dogs
greenfly (aphids) on rose bushes
disease - causing bacteria in humans e.g tetanus
liver fluke, flatworm that lives on cattle and sheep
126
where are parasites important
in controlling wild populations
127
commensalism
two organisms of different species live together where one benefits and the other neither benefits nor is it harmed
128
example of commensalism
birds nesting on a tree
129
population dynamics
the factors that affect the size of a population
130
examples of population dynamics
food availability, predators, birth, death, disease/parasite, migration in or out of an area , human activity, climate
131
3 ways in which humans impact on ecosystems
pollution
conservation
waste management
132
pollution
any harmful addition to the environment
133
substances that cause pollution
pollutants
134
3 examples of pollutants
industrial waste enters rivers and kills fish and plants
| untreated sewage released into lakes and rivers can contaminate drinking water supplies and cause disease
135
one air pollutant
CO2
136
CO2 contributes to
greenhouse effect
137
CO2 levels rising due to
increased combustion of fossil fuels
| increased deforestation
138
2 effects of global worming
rising sea levels
| rising temperatures
139
control of CO2
| power stations
change from burning fossil fuels to renewable energy sources such as wind power, solar energy or hydroelectricity
140
control of CO2
| transport
change from private transport to public transport
141
control of CO2
| electricity
reduce consumption of electricity in commercial places and in homes
142
control of CO2
| plants
plant more trees to absorb carbon dioxide
143
4 pollutants from fossil fuels and their effects
CO2
SO2
smoke particles
CO
144
CO2
increasing levels causing global warming
145
SO2
causes acid rain
146
effects of acid rain
kills plants and animals, human breathing problems , reduced soil fertility, damage to buildings
147
smoke particles
may irritate human lungs and cause cancer
| block sunlight and reduce photosynthesis
148
CO
combines with haemoglobin and reduced amount O2 carried in blood, may cause headaches
149
conservation
the management of the environment
150
benefits of conservation
```
maintains biodiversity
prevents extinction
maintains source of valuable chemicals (medicine)
promotes recreation and tourism
prevents pollution of air and water
```
151
one conservation practice
forestry
152
forestry
cutting down trees is regulated
new tees planted
deciduous and coniferous trees planted for variety
153
what does a variety or trees do?
encourages different birds and insects to survive
154
destruction of forest
brought to public awareness by the use of visitor centres and educational programmes
155
why are forests important
| dependence
many organisms depend on the trees for food and shelter
156
why are forests important
| erosion
trees prevent soil erosion, prevents topsoil from being washed away in rain water, this topsoil ends up in river beds as silt
157
why are forests important
| greenhouse gases
trees reduce the greenhouse effect by absorbing carbon dioxide from the air
158
why are forests important
| floods
absorb rainwater and prevent flooding
159
why is waste management necessary
to prevent pollution as much as possible
160
rising population has led to
huge increase in the amount of waste
161
3 ways to dispose of waste
stored in landfill sites
recycled
destroyed in incinerators
162
2 problems associated with waste disposal
shortage of landfill sites
| landfill sites are unsightly, smelly and pollute local H2O
163
waste products in forestry
small branches, roots, tree stumps and sawdust
164
2 methods of waste disposal in forestry
spread on floor and allowed to rot down naturally
| large branches reduced to sawdust and used to make MDF
165
3 roles of microorganisms in waste management
anaerobic digestion (digestors)
composting
treatment of sewage
166
3 products of anaerobic digestion
methane gas (fuel)
solid (sludge) for compost
liquid rich in nutrients (fertiliser)
167
composting
the breakdown of plant waste under aerobic conditions by bacteria and fungi.
168
what is sewage made up of?
waste domestic water treated in a sewage plant
169
what is increasing human population due to?
increase in birth rate and decrease in death rate
170
4 factors affecting growth in human population
disease
famine
war
contraception
