Life On Earth Flashcards
(120 cards)
0
Q
What is a population?
A
The total number of one type of organism in an ecosystem.
1
Q
What is a habitat?
A
The place where an organism lives.
2
Q
What is a community?
A
All the living things in an ecosystem.
3
Q
What is an ecosystem?
A
The living organisms and the non-living components they interact with.
4
Q
What is biodiversity?
A
The variation of species present in an ecosystem.
5
Q
What happens if there is a wide variation of species in an ecosystem?
A
There is a higher biodiversity making the ecosystem more stable.
6
Q
What is an abiotic factor?
A
A non-living factor.
7
Q
What is a biotic factor?
A
A living factor.
8
Q
Grazing is a biotic factor and has a major effect on biodiversity. What does overgrazing cause?
A
Plant species are destroyed.
9
Q
What does under-grazing cause?
A
Small numbers of dominant species.
10
Q
What does intermediate-grazing cause?
A
High biodiversity.
11
Q
Is predators an abiotic factor or a biotic factor?
A
A biotic factor.
12
Q
What are predators effects on biodiversity?
A
Keeping down prey numbers therefore reducing damage to plants and competition between species.
13
Q
What is deforestation?
A
The clearing of forests.
14
Q
What is distribution?
A
Where organisms are found.
15
Q
What is a niche?
A
The role an organism plays within a community.
16
Q
What are biomes?
A
Various regions on our planet distinguished by their climate.
17
Q
Biomes can be land or water. What can the global distribution of a biome be influenced by?
A
Temperature and rainfall.
18
Q
What is a food chain?
A
A diagram showing the feeding relationships within a habitat.
19
Q
What is a food web?
A
A diagram showing the different food chains linked together.
20
Q
What is a producer?
A
An organism that makes their own energy?
21
Q
What is a primary consumer?
A
Organisms that eat the producers.
22
Q
What is a secondary consumer?
A
Organisms that eat the primary consumers.
23
Q
What is a tertiary consumer?
A
Organisms that eat the secondary consumers.
24
What is each level of the food chain known as?
A trophic level.
25
What do food chains always start with, the producer or a consumer?
The producer.
26
What do the arrows in a food chain show?
The direction of energy flow.
27
How can energy be lost from the food chain?
Movement, heat and undigested food.
28
How much energy is lost at each trophic level and how much energy is passed on?
90% of energy is lost at each trophic level and only 10% is passed on.
29
What is a pyramid of numbers?
A pyramid diagram that shows the population at each trophic level.
30
What is a pyramid of biomass?
A pyramid diagram that shows the dry mass of each population at each trophic level.
31
What is a pyramid of energy?
A pyramid diagram that shows the energy at each trophic level.
32
Normally as you go up the trophic levels the organisms get larger and the population numbers get smaller. There is one exception, what is it?
In a pyramid of numbers the producer can be large like an oak tree.
33
What is a herbivore?
An organism that only eats plant or vegetation.
34
What is a carnivore?
An organism that only eats animals.
35
What is an omnivore?
An organism that eats both animals and vegetation.
36
Nitrogen is used by organisms to make what?
Proteins.
37
The nitrogen cycle shows what?
How nitrogen is used and recycled on the earth.
38
The nitrogen gas in the air gets converted into nitrates in the soil through a process called...?
Nitrogen fixation.
39
What type of bacteria is converted the nitrogen gas into nitrates?
Nitrogen fixing bacteria.
40
Nitrogen fixing bacteria is also present in what?
In the root nodules of legumes so that they can take the nitrogen gas straight from the air.
41
What other process can cause nitrogen fixation?
Lightening.
42
The plants that contain these nitrates will be eaten by other organisms. What is the next stage of the nitrogen cycle?
The animal will produce waste and possibly die and will decompose by bacteria and fungi.
43
After the decomposition of animal waste, the process nitrification begins. What is this process?
Carried out by nitrifying bacteria the waste is converted into ammonia compounds and then they are converted into nitrites which are finally converted into nitrates in the soil.
44
The nitrates in the soil can also be converted back into the air through a process called... and carried out by...?
The process is called denitrification and is carried out by denitrifying bacteria.
45
What does nitrifying bacteria do?
Converts ammonia compounds into nitrite and then to nitrates.
46
What does nitrogen fixing bacteria do?
Converts nitrogen gas into organic nitrates in soil and plants.
47
What does denitrifying bacteria do?
Converts nitrates into nitrogen gas.
48
What is competition?
When organisms compete for the same resources.
49
What is interspecific competition?
Competition between members of different species.
50
What is intraspecific competition?
Competition between members of the same species.
51
What is a key?
A diagram to identify a species or an organism.
52
There is two types of key what are they called?
Branching key and paired statement key.
53
What is light intensity?
How much light an area receives. Is a abiotic factor.
54
What is a light meter?
Something that measures light intensity.
55
Possible errors with measuring light intensity?
Casting a shadow over the meter or not taking enough measurements.
56
What is moisture level?
How much moisture is present in an area.
57
What is a moisture meter?
Something that measures moisture level.
58
Possible errors of moisture meter?
Moisture left on probe as not wiped between samples or not taking enough measurements.
59
What is pH?
A measure if acidity or alkalinity in an area.
60
What is a pH probe?
Something that measures pH.
61
Possible error with a pH probe?
Soil left on probe or not taking enough samples.
62
What is temperature?
How hot or cold an area is.
63
What is a thermometer?
Something that measures temperature.
64
Possible errors with a thermometer?
Holding in direct sunlight or holding the bulb in your hand or not taking enough samples.
65
What does ROAR stand for?
R epeat
O btain
A verage
R eliable
66
What is a pitfall trap/tullgren funnel?
A pot that is placed in the ground to estimate the number of ground dwelling organisms.
67
Possibly errors with pitfall traps and solutions?
Water getting in when it rains- put a few pin pricks in the bottom to allow drainage.
Birds taking trapped animals- put a raised lid supported by pebbles.
Organisms eating other organisms- checking the trap regularly.
68
What is a quadrat?
A square frame used to estimate non-moving organisms in an area.
69
For reliability what must you do when using a quadrat?
Throw quadrat at random and take multiple samples.
70
What does transect mean?
Samples are taken in a long line to show effects of changing conditions.
71
What is a gene?
A section of DNA that codes for 1 protein.
72
What is alleles?
Different versions of a gene.
73
We inherit 2 versions of a gene from where?
One allele from the mother and one allele from the father.
74
What is a mutation?
A random change in genetic material.
75
What is a mutagenic agent?
A factor that increases rate of mutation.
76
Rate of mutation can be increased by what?
Radiation, chemicals, etc.
77
Mutations can a disadvantage or an advantage. What is a disadvantageous mutation?
An unfortunate, harmful mutation that disrupts working cells.
78
What is an advantageous mutation?
A fortunate mutation that improved survival chances.
79
What would happen without advantageous mutations?
Species would stay the same and there would be no evolution.
80
Extra sets of chromosomes occurring in fruit and vegetables cause what?
The fruit and vegetables increase in size and yield.
81
What is a polyploid?
Fruits and crops that have extra complete sets of chromosomes increasing their size and yield.
82
What is meant by variation?
Differences between offspring due to sexual reproduction.
83
Variation allows what?
Allows species to evolve over time in response to environment.
84
There are two types of variation. What are they?
Continuous variation and discontinuous variation.
85
What is continuous variation?
A range of values between a minimum and maximum.
86
What is discontinuous variation?
Distinct, clear cut groups.
87
What is natural selection?
Survival if organisms best adapted to their environment.
88
What is survival of the fittest?
Survival of organisms with a favourable characteristic or select advantage.
89
Only the best adapted individuals survive to reproduce passing on genes with select advantages. What are the stages of natural selection?
1. Production of offspring
2. Variation between offspring
3. Struggle for existence (selection pressures)
4. Survival of the fittest
5. Genes passed onto offspring
90
What is the definition of species?
Organisms with the same genes that interbreed to produce fertile offspring.
91
What is speciation?
The formation of a new species.
92
What are the stages of speciation?
Large freely interbreeding species (one species).
Isolation barrier preventing gene flow- geographical, ecological, reproductive.
Mutation arise in both sub populations.
Natural selection happen over a long period of time as subpopulation adapt.
Two new species suited to their environment.
93
What would happen if the isolation barrier was taken away after the speciation process?
The two populations which were originally one would not be able to produce fertile offspring.
94
What is an adaptation?
A change in an organism allowing it to survive in its environment.
95
What is a fertiliser?
Man made chemical nutrients for crops/plants.
96
Overuse of fertilisers can cause pollution as they can run off fields into waterways. What is this called?
Leaching.
97
This leaching causes algal blooms and eutrophication. What else does this lead to?
Reduction in oxygen levels causing a dead zone where organisms can not survive.
98
How can farmers prevent eutrophication?
Spread fertilisers in the right condition and when their crops are most active.
99
What are the main minerals needed by plants?
Nitrogen, N , for leaf growth.
Phosphorus, P , for root growth.
Potassium, K , for flower and fruit growth.
Magnesium, Mg, for chlorophyll.
100
What happens when plants lack in nitrogen?
Growth decrease.
Leaves pale green and yellow.
Leaf bases red.
Roots long and thin.
101
What happens when plants lack in phosphorus?
Growth decrease.
| Leaf bases red.
102
What happens when plants lack in potassium?
Growth decrease.
Early death of older leaves.
Poor flowers and fruit.
103
What happens to plants that lack in magnesium?
Growth decrease.
| Leaves pale green and yellow.
104
What is leaching?
The process which fertilisers flow into waterways.
105
What is eutrophication?
The process which a waterway becomes a dead zone. -excess of nutrients in waterway.
106
What is the stages of eutrophication?
Farmers spread fertilisers.
Nutrients leach into waterways.
Algal bloom covering surface and reducing oxygen and sunlight.
Plants below die and decompose by bacteria using more oxygen.
Phytoplankton rapidly increase due to nutrients.
Water becomes a dead zone as a result of oxygen depletion.
107
What is an algal bloom?
Rapid increase of algae due to extra nutrients.
108
What are decomposed?
When oxygen concentration in water is highly reduced resulting in unable living conditions.
109
What is a dead zone?
A habitat that can not sustain life.
110
What is a pesticide?
A man made chemical applied to crops to kill any unwanted insects/animals/competition/disease.
111
What is a herbicide?
A pesticide that reduces competition from other plants.
112
What is a fungicide?
A pesticide that prevent and reduces an attack from fungi.
113
What is an insecticide?
A pesticide that prevent and reduces an attack from insects.
114
Pesticides can get into the food chain and cause environmental harm. Why can they cause harm?
They can accumulate in the bodies of organisms over time. As the pesticides are passed along the food chain toxicity increases and can reach fatal levels.
115
What is bioaccumulation?
The build up of pesticides in the food chain.
116
What is an indicator species?
An organism/species that shows the level of pollution in an area.
117
What is a biological control?
The use of natural predators to control pests as alternatives to pesticides.
118
What is a GM cop?
A genetically modified crop.
119
Foreign genes are inserted into crops to improve their characteristics. How does this improve the modified crop?
Bigger yields, bigger crops and fruits and disease/pest resistant.
