ch 19 Flashcards
1
Q
define population
A
a group of living organisms of same species, living in the same place at the same tine
2
Q
define community
A
a group of population of different species , living in an ecosystem
3
Q
define ecosystem
A
a community of living organisms + non-living components (their surronding enviroment)
4
Q
what type of organism is a producer
A
auto-trophic organism
5
Q
define producer
A
self-feeding organism , organisms which depend on themselves in making their food
6
Q
what type of organism is a consumer
A
hetero-trophic organism
7
Q
define consumer
A
others-feeding organism, organism that depend on other organisms to obtain their food
8
Q
what type of organisms are decomposers
A
saprophytic organisms
9
Q
define decomposer
A
organisms which feed on dead bodies causing decay, they produce enzymes that digest the dead bodies into simple soluble substances to feed on
10
Q
types of consumers [3]
A
-herbivores
-carnivores
-omnivores
11
Q
define herbivores
A
consumers that feed on plants only
12
Q
define carnivores
A
consumers which feed on flesh (meat) only
13
Q
define omnivores
A
consumers which feed on both plants and flesh
14
Q
importance of decomposers [2]
A
-prevent accumulation of dead bodies and spread of diseases
-increase the ferility of soil by releasing useful substances from dead bodies
15
Q
define food chain
A
it is a sequence by which chemical energy in the form of food is transferred from one organism to another
16
Q
how is the sun the source of all energy in the ecosystem
A
as its the form of energy absored by green plants to make photosynthesis and produce energy
17
Q
how much of the sunlight is used by the plant to make photosynthesis
A
1%
18
Q
why is only 1% of the sunlight used in photosynthesis by the plant [3]
A
-some of the sunlight pass through the leaf without being trapped
-some sunlight is reflected from the surface of the leaf
-some of the sunlight fall on non-photosynthesizing surfaces
19
Q
why wont the primary consumer not take all the energy consumed by green plants [2]
A
-the primary consumer doesnt eat all parts of the plant
-the primary consumer doesnt digest all parts of the plant
20
Q
why will the secondary consumer receive less and less energy from the primary consumer[4]
A
lost in:
-movement , to search for food and escape from enemies
-respiration, where heat energy is lost with warm expired air
-excretion, where heat energy is lost with warm urine
-egestion, where heat energy is lost with warm faeces
21
Q
what decreases down the group [3]
A
-number
-mass
-energy
22
Q
advantage of a short food chain
A
less loss of mass and energy
23
Q
why is there an increased efficiency of feedinng green plants to humans
A
because when humans feed on green plants, theyll be considered primary consumer hence recieving more enrgy than the enrgy recieved if they were secondary or tertiary consumer
24
Q
disadvantages of being a vegetarian [2]
A
-not reccieving animal proteins which are used for growth and tissue repair
-not recieving animal fats which are used to produce energy
25
why are big fierce animals rare in the ecosystem
becuase as we go along the food chain there is energy loss , so stom big animals from recieving enough energy
26
define food web
a series of interconnected food chains
27
cause of the food web
one organism feed on many other organisms , leading to connection of food chains together
28
advantage of the food web [2]
the organism will:
-have a constant supply of food , even if one of his food species , die or extinct
-recieve more energy from 3 food chains instead of 1 food chain
29
define food pyramid
a diagram of food boxes placed over each other to represent the relationship inside the food chain
30
types of food pyramids [3]
-pyramid of numbers
-pyramid of mass
-pyramid of energy
31
what does the size of each box represent in a food pyrmaid
the number of the dry mass of the enrgy of each tropic level
32
advantage of pyramids of biomass rather than pyramids of number? [4]
-they are always regular
-they are more accurate, because they measure the actual mass of material inside the living organism
-indicates how much energy is left
-in the pyramid of number ,the size of the box of one large organism is the same as one small organism ,so less accurate
33
define trophic level
the position of the organism n the food chain/web/pyrmaid
34
in carbon cycle how is CO2 added to the atmosphere [3]
-respiration of plants and animals
-decay of dead bodies of plants and animals
-combustion of fossil fuels
35
how is co2 removed from the atmosphere in the carbon cycle
by photosynthesis
36
why has Co2 increased more then o2 in the past 100 years [2]
-excessive combustion of fossil fuels , so much production of co2
-deforestration , so no removal of co2 from the atmosphere by photosynthesis
37
stages of nitrogen cycle [4]
-decay
-nitrogen fixation
-nitrification
-denitrification
38
describe the decay stage of the nitrogen cycle
-proteins in the dead bodies are broken down by decomposers protease anzyme to give amino acids and ammonia
39
describe nitrogen fixing stage of the nitrogen cycle
nitrogen gas is turned into ammonium by nitrogen fixinng bacteria (nodular bacteria) present in root nodules of leguminous plants
40
describe stage 3 of nitrification [3]
-the ammonia from decay stage and the ammonium from nitrogen fixing stage are oxidized by the nitrifying bacteria to become nitrites
-the nitrites are further oxidized to become nitrates
-the nitrates are absorbed by plants by the roots from the soil to form proteins
41
needs of nitrifying bacteria [3]
-need o2 for aerobic respiration
-need well aerated soil
-need regular ploughing
42
function of nitrifying bacteria
increase soil fertility
43
what does denitrifying bacteria
make reduction by anaerobic respiration
44
needs of denitrifying bacteria [2]
-non-aerated soil
-water-logged soil, air spaces filled with water
45
why is denitrifying bacteria harmful
descrease soil fertility
46
how to increase soil fertility [3]
-add fertilizers (nitrate fertilizers, phosphate, ammonia, urea)
-cultivate leguminous plants whose roots contain nodular (nitrogen fixing) bacteria
-regular ploughing of soil which can make the soil well aerated to encourage nitrifying bacteria that increase soil fertility
47
how to decrease soil fertility? [3]
-over cultivation, excess plants consume soil nitrate
-over grazing
-monoculture instead of crop rotation
48
what is monoculture
its growing the same crop in the same field year after year
49
what is crop rotation
its growing different crop in the same field year after year
50
what is large scale monoculture
an excellent variety of crop plants can be prepared by selective breeding or gentic engerring to have excellent characters and high crop yield , then planted in the same field year after year
51
advantages of large scale monoculture [3]
-allow production of crop plants with excellent characters
-high crop yield
-lower price
52
disadvantages of large scale monoculture [4]
-easy spread of diseases and pests, bcz when same plant is grown in the smae field this allows the pests to complete their life cycle for generations
-the pests will destroy the plants, so no food for consumers , disruption of food chain so extinction of species
-decrease soil fertility and soil erosion , same minerals will be absorbed by the same plant every year
-loss of habitats, places where organisms live , bcz farmers will use all lands to plant the same plant for profit
53
in population growth curve what is lag phase [3]
-slow or no increase in the number of organisms
-because organisms are not reproducing
-as they are still adjusting themselves to the new enviroment still searching for food, water , shelter
54
in population growth curve what is log phase [4]
-marked increase in the number of organisms
-birth rate is more than death rate
-no limiting factors
-there is plenty of food, plenty of water, suitable temp., no diseases, no predators
-no competition
55
in population growth curve what is stable phase [3]
-no increase in the population
-birth rate= death rate
-some limiting factors
56
in population growth curve what is death phase [3]
-decrease in the population
-death rate is more than birth rate
-much limiting factors
57
what are the liming factors [6]
-lack of food
-lack of water
-non-suitable temperature
-spread of diseases
-spread of predators
-competition of food, oxygen
58
what is fluctuating population
a special type if population curve, specific to the prey and its predators
59
describe a fluctuating population [2]
-the population of the prey and their predators fluctuate together, because predators depend on the prey for feeding
-the fluctuation of the prey population starts first followed by the fluctuation of the predator population
60
describe the human growth care over the past years [2]
-human population was increasing slowly till the 19th century
-from the beginning of the 19th century the world population was increased very much
61
why has the human population increase [2]
-more food
-less disease
62
why has there been more food over the past years [2]
-improved agricultural methods, lead to increased plant production
-using artifiical selection and genetic engeneering to increase food production
63
why has there been less disease over the past years [2]
-improved medical care and treatment of diseases
-discover vaccines and new drugs and antibiotics
64
average life expectency in developing countries
54
65
average life expectancy in developed countries
74
66
reasons for difference in life expectancy in developing and developed countries [2]
-more spread of diseases , less foodless balanced diet in developing countries than developed cpuntries
-more medical care , more health facilities in developed countries than developing countries
67
how in developed countries do farmers increase the production of milk , meat, wool ? [2]
-high energy foods are bought to feed them
-medication may be given to stop the development of disease
68
big disadvantages of intensive livestock [3]
-livestock suffer in crowded conditions in which they are kept , disease can spread easily among them
-giving the animals regular doses of antibiotics , increase the risk that bacteria will develop resistance of the antibiotics
-the wastes from them can pollute land and waterways nearby
69
define deforestation
means removal of forests or cutting down of trees by humans to use them
70
reasons for deforestation [4]
-using wood of trees to make paper, windows and furniture
-using wood of trees as a source of energy
-using land of forests to cultivate crop plants
-using land of forests to build new cities
71
measures to reduce the harmful effects of deforestation [4]
-recycling of paper (use aluminum in windows instead of wood)
-using alternative sources of energy
-cultivate crop plants in deserts instead of forests
-build new cities in deserts instead of forests
72
effects of a slower rate of photosynthesis [2]
-dec. conc. of atmospheric o2
-inc. conc. of atmospheric Co2 so greenhouse effect
73
effects of a slower rate of transpiration
-less evaporation of water vapour from surface of the leaves , so less clouds are formed , decreased rain fall, decreased plant growth
74
effects of removal trees that destroy the shelter of birds
-reptile and many small animals get extinct , disturbance in ecosystems and enviromental balance
75
effects of removal of trees with strong branching roots [2]
-since they hold the soil particles together it will lead to soil erosion, this is because the soil particles will be blown away by either wind or water
-roots of trees no longer absorb rain water and make land slides and mud slides
76
how is air pollution formed
-humans burn fossil fuels , and they produce many harmful gases like CO2 and SO2
77
what is greenhouse effect [3]
-normally the earth's surface reflects the light rays coming from the sun to the outside atmosphere , but in the last few years the concentration of atmospheric CO2 has increased due to excessive burning of fossil duels and deforestation
-this increased CO2 gas escape to the atmosphere surronding the earth and traps the infrared rays of the sun reflected from the sun reflected from the earth's surface
-infrared rays have heating effectso they heat the atmospheric air surronding the earth, increasing tge temperature of the earth and melting the polar ice caps , raising levels of seas and oceans so floods
78
what gases lead to global warming? [3] and what are their sources? and their percentage in contributing to global warming?
-co2 (55%), due to deforestation and burning of fossil fuels
-methane (15%) , due to decay of organic matter
-CFC's (30%) , from air conditioners or refrigators
79
effects of cattle farming on atmosphere
-large number of cattle will produce organic wastes which will decay producing methane gas that contributes to global warming
80
what happens when raw untreated sewage is released into a river? [3]
it will be a source of food for bacteria in the river
-bacteria will feed , divide , increase in number and respire aerobically , which wil consume the oxygen dissolved in water, so less oxygen is available for fisj and marine animals and they will die
81
how is water polluted by excess nitrates and phophates [3]
-excess nitrates are washed by rain water to the river
-nitrates in the river are good for green algae that grow rapidly and accumulate on the water surface to form a barrier that prevent passage of light and oxygen to plants under water
-death of plants then producers then decomposers ...so death of fish and all of marine life
82
problems of non-biodegradble substances [3]
-if burnt ,will cause pollution
-if thrown in sewage, will block the sewage pipes
-if left untreated, will kill small animals
83
what is the only way to get rid of non-biodegradble substnaces
recycling
84
enviromental problems caused by non-biodegradble plastics thrown in rivers and streams [5]
-plastics accumulate over the water surface to form a barrier that blocks passage of light so no photosynthesis so death of aquatic plants
-plastics accumulate over the water surface to form a barrier that blocks passage of oxygen so no respiration so death of aquatic animals
-plastics may be eaten by fish that block their intestine
-plastics may release toxins to the water
-plastics may block flow of water in narrow parts of stream , rivers
85
define conservation
conservation means keeping the components of the enviroment as they are without being damaged
86
why do we need to make conservation [2]
-to protect the endangered species from extinction because an organism's role in he enviroment is to keep enviromental balance
-to conserve the ecosystem (soil, plants, animals) , which act as resources for for food, medicene , fuel
87
how to conserve an endangered mammal [5]
-avoid hunting of the animal
-avoid destruction of the habitat where the animal lives
-zoos provide optimum condition for the animal to live in (captive breeding)
-avoid pollution of the habitat
-removal of alien species
88
what are causes of mass extinction [5]
-hunting of the animals
-destruction of the habitat where the animal lives
-lack of food and water / spread of diseases
-pollution of habitat
-introduction of alien species
89
define biodiversity
no. of living organisms of different species that live in an area
90
define endangered species
a species whose numbers have descreased so low that they are at risk of becoming extinct , they may reduce gentic variation and evolution
91
what are sustainable resources
a resource that when removed from the enviroment , it is reproduced again rapidy so that it does not run out and we can keep using it
92
how can we conserve forests [3]
- goverments can refuse to give lisences to companies who want to cut down forests
-instead of cutting down all the trees in a forest , just a small proportion of trees are cut down (selective felling) , the remaining trees will hold the soil in place and will continue ti provide habitats for animals
-many trees will regrow after they are cut down ,trees can be cu down to abt 1 meter and then left to regrow this is called coppicing
93
how to conserve fish [3]
-quotas, allow fishermen to catch only a certain quantity of fish depending on wether the type of fish is not under threat or ubder threat of extinction
-goverment can ban or regulate catching of threatned species by using wide mesh size nets to avoid catching small fish
-keep them in fish hatcheries and then release them (restocking) , by placing male and female in containers with optimum conditions ti breed and increase in number
94
disdvantage of quotas
it is difficult for fishermen to catch only one species of fish as they can accidentaly catch other species
95
disadvantage of restocking [2]
-overcrowding so easy spread of diseases
-accumulation of waste produvt which is toxic to fish and make water polution
