Unit 3 Flashcards
(279 cards)
1
Q
What do density-dependant factors include?
A
- competition for nutrients
- the transmission of disease
- the level of predation
- the build-up of toxic wastes
2
Q
what is population density?
A
the number of individuals present per unit area (or volume) of a habitat
3
Q
What happens when a population density increases?
A
each individual has access to fewer resources
4
Q
What is our human populations dependant upon?
A
sufficient and sustainable food production from the harvest of a relatively narrow range of crop and livestock species
5
Q
What is food security?
A
the ability of human populations to access food of sufficient quality and quantity
6
Q
What do humans rely on to increase crop yields worldwide?
A
use of fertilisers and pesticides
7
Q
Why must agriculture methods change?
A
to minimise the damage and degradation of natural resources
8
Q
What do autotrophs (producers) use the light from the sun for?
A
to synthesise sugars and other organic compounds, which they use as fuel for cellular respiration and building materials for growth.
9
Q
What do autotrophs include?
A
plants and algae
10
Q
What is Arable land?
A
land which is suitable for growing crops
11
Q
What do agricultural productions depend on?
A
factors that control plant growth
12
Q
Factors that affect plant growth include:
A
- temperature
- moisture
13
Q
What does the level of soil nutrients affect?
A
productivity and yield of crop plants
14
Q
What do water irrigating systems do?
A
increase the availability of water
15
Q
What do greenhouse and polythene tunnels do?
A
provide shelter and controls the temperature and wind exposure
16
Q
What do fertilisers do?
A
improve soil mineral levels
17
Q
Factors to improve efficiency include:
A
- breeding of higher yielding cultivars
- protection of crops from pests
- protections of crops from diseases
- protections of crops from competition
- use of fertilisers
18
Q
what is a Cultivar?
A
(Cultivated Variety)
a plant selected for desirable characteristics
19
Q
Problems associated with upkeep of livestock ;
A
livestock produce less food per unit area than plant crops due to loss of energy between trophic levels.
20
Q
How much energy is lost between each level?
A
90%
21
Q
Why are food chains relatively short?
A
because of the inefficiency of energy transfer along the chain
22
Q
Energy enters most ecosystems as what?
A
sunlight
23
Q
What is Net Assimilation?
A
Increase in mass due to photosynthesis - loss due to respiration
24
Q
How can net assimilation be found?
A
by measuring the increase in dry mass per unit leaf area
25
What is productivity?
the rate at which plants accumulate or generate new biomass over a period of time.
26
what is productivity measured in?
grams per square metre per year
27
What is of low economic value?
a wheat stalk
28
What is of high economic value?
a kernel
29
What is a biological yield?
the total biomass produced
30
what is a economic yield?
the biomass of the desired product
31
What is harvest index?
Dry mass of economic yield
-----------------------------------------
Dry mass of biological yield
32
What absorbs sunlight?
a plants leaves
33
What is the energy of sunlight converted to?
chemical energy of food
34
Where does photosynthesis occur?
chloroplasts
35
What is the equation for photosynthesis?
carbon dioxide + water + light energy ----> glucose + oxygen
36
Light is a form of energy known as what?
electromagnetic energy
37
What 3 things can happen to light when it hits an object?
- reflected
- transmitted
- absorbed
38
Substances that absorb light are known as what?
pigments
39
Why does a leaf appear green?
contains the pigment chlorophyll
40
Where is the chlorophyll contained within?
Thylakoid membrane
41
What is the space within the chloroplast called?
stroma
42
The ability of a pigment to absorb various wavelengths of light can be measured with what?
Spectrophotometer
43
what does an absorption spectrum show?
the "amount" of light energy absorbed by a pigment at each wavelength
44
What are the 4 main photosynthesis pigments?
- chlorophyll a
- chlorophyll b
- carotene
- xanthophyll
45
What are the Carotenoids made up of?
carotene and xanthophyll
46
What are accessory pigments?
broadened or extended range of wavelengths absorbed by the leaf
47
What is an action spectrum?
shows the rate of photosynthesis at each wavelength
48
What drives the rate of photosynthesis to the greatest extent?
red and blue light
49
What are "packets" of energy known as? (light)
photons
50
What are the two processes in photosynthesis?
- light reactions
| - Calvin cycle
51
Where does the first process take place?
Thylakoid membrane
52
What is split to provide a source of electrons and protons(H+) and oxygen?
Water
53
What does the light absorbed by the chlorophyll do?
drives the transfer of the electrons and hydrogen ions to an acceptor
54
what is the name of the acceptor in the first process of photosynthesis? and what is its function?
NADP+
| temporarily stores the electrons and hydrogen ions
55
What generates ATP?
light reactions
56
What is photophosphorylation?
the addition of a phosphate group to ADP, during the light stages
57
What are photosystems?
Chlorophyll molecules that are situated along protein complexes
58
What is light said to do to the electrons?
"excite"'
59
What are "high-energy" electrons transferred across to generate ATP?
electron transport chains
60
What happens to oxygen during the light reactions?
it is evolved
61
What happens to hydrogen during the light reactions?
transferred to the coenzyme NADP
62
What happens to NADP when it is reduced ?
NADPH
63
What happens during the electron chain stage?
protons are pumped into the thylakoid lumen, providing the driving force for synthesis of ATP via ATP synthase
64
What is the role of NADPH?
"'shuttles" the energy to the Calvin cycle
65
What else is energy used for?
photolysis
66
Where does the Calvin cycle take place?
the Stroma
67
What does the Calvin cycle use the products of the light reactions for?
to synthesise sugar from CO2
68
What are the 3 phases of the Calvin cycle?
- carbon fixation
- reduction
- regeneration of RuBP
69
What is the equation for carbon fixation?
RuBisCO
| RuBP + CO2 -------------> 3 - PGA
70
What is the equation for reduction?
ATP -------------------------> ADP
3 -PGA --------------------> G3P
NADPH ---------------------> NADP
71
What does RuBP stand for?
Ribulose Bisphosphate
72
What does 3-PGA stand for?
3-phosphoglycerate
73
What does G3P stand for?
Glyceraldehyde-3-phosphate
74
what happens to the remaining 5 molecules of G3P?
recycled
75
What is the starting material for metabolic pathways that synthesise organic compounds?
G3P
76
Examples of organic compounds?
Glucose, sucrose, cellulose and starch
77
What does intensive farming reduce?
species diversity
78
What is a weed?
any plant that grows where it is not wanted
79
What are the 2 types of weeds?
- annual
| - perennial
80
What is an annual weed?
completes its life cycle in 1 year
81
Properties of an annual weed:
- rapid growth
- short life cycle
- high seed output
- long-term seed viability
82
Give an example of an annual weed.
chickweed
83
What is a perennial weed?
persists from one year to the next
84
Properties of a perennial weed
- storage organs
| - reproduce vegetatively
85
Give an example of a perennial weed
Dandelion
86
What are the 3 invertebrate groups which are crop pests? and give an example
- Insect (aphid)
- Nematode worms (potato cyst)
- Mollusc (snail)
87
What does a plant disease alter?
plants growth, appearance or function
88
What do pathogens include?
bacteria, fungi and viruses
89
How are most pathogens transmitted?
by invertebrates
90
What 2 factors are important to the success of the pathogen?
temperature and moisture
91
What are the results of a pathogen?
- reduction in plant health
- a lower productivity
- poorer yield of crop
92
What does the genetic uniformity of the crops create?
a population that is at a high risk of any pest
93
What creates a uniform habitat?
large scale monocultures
94
Examples of cultural practises
- ploughing
- time of sowing
- weeding
- removal of crop residue
- crop rotation
95
What are the 2 types of chemical agents?
- selective
| - systemic
96
examples of chemical agents and their actions
- Herbicide (kills weeds)
- pesticide ( pests)
- Insecticide (insects)
- Molluscicide ( molluscs)
- Nematocide (nematodes)
- Fungicide (fungi)
97
What does a systemic herbicide do?
destroys the whole plant
98
What does a selective herbicide do?
will only kill broad-leaved plants
99
What are the optimal conditions for fungal growth?
- high humidity
- high moisture levels
- moderate temperatures
100
Why are air temperatures and humidity levels monitored every hour?
predict the most suitable time to spray crops with fungicides
101
What is the Smith Period?
the period when a crop plant is at greatest risk to infection
102
What should plant protection chemicals be?
specific, short-lived and relatively safe
103
What happens to toxic molecules as they are passed along the food chain?
become more and more concentrated at each level
104
What Is a toxic pesticide?
DDT
105
What effect does biomagnification have?
relatively harmless pesticides can become rapidly lethal in top predators
106
What is biomagnification?
chemicals build up in the cells of the organism and increase in concentration at each transfer
107
What is bioaccumulation?
build up in the cells of organisms to a higher concentration than in the surrounding environment
108
What is persistence?
not broken down in the bodies of the organisms
109
What is resistance?
organisms which are not affected by the pesticide
110
What is a biological control?
the control of a pest population through the deliberate introduction of another organism that is a potential threat or "enemy"
111
What are 3 types of biological controls? and give some examples
- Predator (aphid--ladybug)
- Parasite (whitefly)
- Pathogen (leaf eating caterpillar)
112
What are the risks of biological control?
- introduced species may become pests
- may introduce disease and parasites
- may disrupt food webs and food chains
- may out-compete native species and reduce biodiversity
- may eat and destroy native plants
- acts as predators to native species
113
What does integrated pest management involve?
a combination of techniques to lower pest populations and reduces the need for pesticides
114
what will most IPM programmes combine?
cultural, chemical and biological controls together
115
How can an animals wellbeing be measured?
through observations of their displayed behaviours
116
What are the 5 Freedoms of animal welfare?
Freedom from
- hunger and thirst
- discomfort
- pain, injury and disease
- fear and distress
- freedom to express normal behaviour
117
What do the 5 Freedoms require?
- set of environmental conditions
| - can initially be very expensive
118
Benefits of animals reared in stress free and improved living conditions?
- grow better
- breed more successfully
- produce higher quality products with greater yields
119
In the UK, who is the additional cost passed onto?
the consumer
120
What do ethics refer to?
moral values and rules
121
What are the unacceptable standards which an animal should not face?
overcrowding, hygiene and poor quality food
122
What are the ethical impacts of a good animal welfare?
- better quality of life
- less stress
- natural behaviours
- less susceptible to disease
123
What are the ethical impacts of a poor animal welfare?
- poor quality of life
- stressed behaviours
- invasive treatments
124
What do behavioural indicators include?
- stereotypy
- misdirected behaviour
- failure in sexual and reproductive behaviour
- altered level of activity
125
What is Ethology?
the study of animal behaviour in its natural or semi-natural setting
126
What is an Ethogram?
a list of all observed behaviours and the length of time an animal displays these.
127
What word describes " the attribution of human motivation, characteristics or behaviour to non-human animals" ?
Anthropomphism
128
What is important when observing an animals behaviour?
not to draw conclusions based on parallels with human behaviour
129
What kind of test can be set up to establish the conditions an animal "prefers"'?
preference tests
130
What drives an animal to behave or act in a particular way?
Motivation
131
What is motivation?
the process that arouses and directs an animal's behaviour to satisfy on of the basic needs
132
What is the definition of Symbiosis?
a co-evolved intimate relationship between members of two different species
133
What are larger organism knows as?
host
134
What are smaller organisms knows as?
symbiont
135
what is Parasitism?
When a parasite lives within the host organism or on the surface
136
How does the parasite benefit from living in the host or on the surface of it?
it receives energy or nutrients from the host
137
How is host harmed by parasitism?
by the loss of nutrients
138
Transmission of parasites to new hosts involves what? (3)
- direct contact
- resistant stages
- use of a vector
139
What is Direct contact?
When the parasite is passed directly from one host to another; when the two hosts come into close physical contact with one another
140
What are resistant stages?
when parasites can survive through extreme conditions, can survive out with their host for some time
141
What is a vector?
an intermediate organism that transfers a parasite from one host to the next
142
What does a life cycle of a parasite require?
two or more hosts for completion
143
What kind of metabolism do parasites have?
very limited
144
What is Mutualism?
an interdependent relationship that benefits both species
145
What 2 cells display similarities with bacteria?
mitochondria and chloroplasts
146
What does the endosymbiont theory state?
an early ancestor of eukaryotic cells engulfed an oxygen-using non photosynthetic prokaryotic cell, eventually the engulfed cell formed a relationship with the host cell
147
What is an endosymbiont?
a cell living within a cell
148
The difference in DNA between chloroplast and nucleus
Chloroplast has circular DNA and nucleus has linear DNA
149
What is artificial selection?
a form of selection in which humans actively chose which traits should be passed onto offspring
150
Animal and plant hereditary has been manipulated to improve what?
plant crops
animal stock
and to support sustainable food production
151
Breeder develop improved crops and animals with what traits?
- higher food yields
- higher nutritional values
- pest resistance
- disease resistance
- ability to thrive in particular environmental conditions
152
What can GM plants increase?
the quality and quantity of food
153
What to field trials involve?
breeders conducting a series of trials in their pursuit of developing new varieties.
154
Where will a field trial be carried out?
carried out in the organism's natural environment
155
Why are field trials carried out?
to compare the performance of different cultivars or treatments and to evaluate GM crops.
156
In a field trial, the area of land will be divided into what?
equally sized plots
157
What factors must be considered when planning field trials ?
- selection of treatments
- number of replicates
- randomisation
158
What does the selection of treatments ensure?
- this ensures there is a fair comparison
159
What does the number of replication ensure?
several replicates take account of the variability within the sample
160
What does randomisation eliminate?
eliminates bias when measuring treatment effects
161
What is inheritance? (or heredity)
The transmission of traits from one generation to the next
162
What is genetic variation a consequence of?
sexual variation
163
What does variation contribute to?
evolution through the process of natural selection
164
What is outbreeding?
the mating of unrelated or distantly related members of a species
165
Plants that are cross-pollinated are known as what?
outbreeding
166
Animals that rely on sexual reproduction will be what?
outbreeding
167
What is inbreeding?
the mating of closely relate organisms
168
When does inbreeding occur?
when plants or animals have been selected by humans in breeding programmes.
169
What happens during the breeding programmes? and what does it lead to?
selected animals or plants are bred for several generations until the population breeds "true" o the desired trait.
leads to the loss of heterozygotes
170
What is a gene?
The unit of heredity that controls a characteristic
171
What is a Genome?
The combination of genes that is possessed by an organism e.g. BB, Bb, bb
172
What is a phenotype?
the physical attributes that are observed e.g. black coat in Guinea pig
173
What are alleles ?
Different forms of a gene
174
what is the meaning of Homozygous?
when an organism possesses two identical alleles of a gene e.g. BB or bb
175
what is the meaning of Heterozygous?
When an organism possesses two different alleles of a gene e.g. Bb
176
What is dominant ?
the allele that is expressed in the phenotype
177
What is recessive ?
the allele that is only observed in the phenotype, if homozygous
178
What is polygenic?
a characteristic controlled by the alleles of more than one gene e.g. height
179
What are variations?
Differences observed in members of the same species
180
What are discrete variations?
when the differences are clear cut and can be used to divide up a group e.g. blood group
181
What are continuous variations?
when the differences are not clear cut and they show a wide range of values eg. height
182
Avoiding inbreeding:
some flowering plants possess mechanisms to promote outbreeding and avoid inbreeding
183
summary of inbreeding (self-pollinating plants)
- self-fertilisation
- homozygosity promoted
- recessive, deleterious alleles normally eliminated by natural selection
184
Summary of outbreeding (cross-pollinating plants and animals)
- cross-fertilisation
- heterozygosity promoted
- recessive, deleterious alleles be present but "masked" by dominant alleles
185
What is inbreeding depression?
this accumulation of deleterious recessive alleles
186
What does inbreeding depression result in?
loss in vigour, size, fertility and yields
187
How does natural selection reduce inbreeding depression in self-pollinating plant species?
by eliminating deleterious alleles
188
In outbreeding species, how is inbreeding depression avoided?
by selecting from the desired characteristics while maintaining an otherwise genetically diverse population
189
How do you overcome inbreeding depression?
breeders will introduce new alleles to plant and animal lines by crossbreeding with another organism possessing a different desirable characteristic
190
What process is required to maintain the new breed?
backcrossing
191
What are F1 hybrids?
the individual resulting from a cross between genetically dissimilar members of the same species .
192
What do F1 hybrids creates?
a relatively uniform heterozygous crop
193
what do F1 hybrids often exhibit? and what is this known as?
increased vigour, yield and fertility
| - known as hybrid vigour
194
What can the F2 be used for?
a source of new varieties
195
What is a test cross?
a cross that is used to identify unwanted individuals with heterozygous alleles
196
Agricultural scientists have developed mechanisms that can identify what?
a selected gene or a desirable characteristic, remove it and introduce it to another organism.
197
Agricultural applications:
- breeding
- quality
- disease resistance
198
What is genetic engineering rapidly replacing?
Traditional plant-breeding programmes
199
some transgenic plants have been endowed with desirable traits such as what?
delayed ripening and resistance to disease and spoilage
200
What are the 4 traits in agriculture applications in GM crops?
- herbicide resistance
- pest resistance
- salinity resistance
- improved nutritional value
201
What does social behaviour consist of?
a set of interactions among individuals of the same species
202
What is the benefit of living in groups?
it increases the frequency of interactions between individuals
203
All behaviours associated with conflict is known as what?
Agonistic behaviours
204
What kind of behaviour signifies submission?
appeasement behaviour
205
What does appeasement behaviour replace?
replaces actual attack and defence, and therefore decreases the risk of injury and reduce the energy expenditure involved in resolving conflict
206
What is a disadvantage about living in close contact?
risks the rapid spread of parasites and disease.
207
An advantage about social groups:
safer from predators
208
What is increased survival a result of?
increased protection
209
What 3 factors do social behaviours include?
- social hierarchies
- cooperative hunting
- cooperative defence (social defence)
210
What is social hierarchy?
a social structure in which members of a group are organised into a linear ranking, with each animal dominant over those below it and submissive to those above it in the hierarchy.
211
How is the hierarchy established?
by fighting or display behaviour
212
Which special privileges does a dominant wolf "earn"?
- first choice of food
- first choice of mate
- best sleeping area
213
What are the benefits of social hierarchy?
- reduces conflict and aggression, real fighting is kept to a minimum and serious injury is avoided
- reduces energy loss
- the most dominant animal gets to eat first, ensuring it survives
214
What is cooperative hunting?
when a group of animals work together to catch and share their prey
215
What are the benefits of cooperative hunting?
- increases the chances of actually attacking and killing the prey
- larger prey can be caught, with less pursuit time per individual
- reduced energy expenditure per individual
- subordinate animal may gain more food than by foraging or hunting alone
- food sharing will occur as long as the reward for sharing exceeds that for foraging individually
216
What is social defence?
"safety in numbers" meaning "more eyes" on the lookout
217
Benefits of social defence:
- warns groups of danger
- protection of offspring
- reduces success of the predator
- provides protection for most of the herd
218
What is altruism?
when an animal behaves in a way that is disadvantageous to itself, a donor and beneficial to another animal, a recipient
- unselfish behaviour
219
What does altruistic behaviour in related animals (kin) increase?
increases their "fitness" of the parents, as the survival of their offspring into the next generation maximises their "genetic representation" on the population
220
What variables affect altruism?
- the benefit of the recipient
- the cost of the altruist (donor)
- the relatedness of the donor and the recipient
221
What does relatedness mean?
- the probability that 2 individuals share an allele to recent common ancestry
222
What is kin selection?
Natural selection that favours altruism by enhancing the reproductive success of relatives
223
What does an animal increase by helping close relatives?
increases its genetic representation in the next generation
224
What does reciprocal altruism involve?
one individual, at some cos to itself, giving help to another provided that there is a very real prospect of the favour being returned
225
Examples of social insects;
honey bees, wasps, ants and termites
226
give an example of kin selection in social insects:
most members of the colony are workers who cooperate with close relatives
227
What are keystone species?
species that hold a vital role in an ecosystem
228
What are primates?
a large diverse group of mammals that include monkeys, apes and humans
229
Name a key feature to primate behaviour?
the extended period of parental care
230
what are the 3 types of behaviours in primates?
- alliance
- ritualistic display
- appeasement
231
What is alliance behaviour? (description)
the more allies, the greater chance of being dominant
232
What is ritualistic display?
this intimidates other males
233
What does appeasement reduce?
aggression
234
What is taxonomy?
the classification and naming of organisms into an ordered system
235
What are the factors affecting the complexity of the social structure?
- ecological nice
- the distribution of resources
- taxonomic group
236
What is extinction?
- the process in which organisms die out
| - natural phenomenon
237
When will extinction occur?
if the birth rate is less than the death rate over an extended period of time
238
What is mass extinction?
a rapid decrease in the numbers of species present over a period of time
239
What does mass extinction show?
an increases extinction rate over and above the "'normal background" level
240
Large land animals are known as what?
Megafauna
241
What are the major causes of ecosystem degradation?
- deforestation
- over hunting
- over fishing
- pollution
242
What is the impact of deforestation?
- more CO2
- fewer habitats
- loss of food sources
243
What is the impacts of over hunting?
- declining numbers (of whale populations and elephant herds)
244
What is an impact of overfishing?
reduced numbers
245
What are the impacts of pollution?
- contribution to greenhouse gases
| - leads to eutrophication
246
What are the three levels of biological diversity ?
- genetic diversity
- species diversity
- ecosystem diversity
247
What is genetic diversity?
the number and frequency of alleles in a population
248
What is species diversity?
the number of different species in an ecosystem (species richness) and the proportion of each species in the ecosystem (relative abundance)
249
What is ecosystem diversity?
the number of distinct ecosystems within a defined area
250
what do biogeographic factors contribute to?
the range of diversity observed in biological communities
251
What is a true island?
land mass permanently surrounded by water
252
What is a habitat island?
an isolated area on land surrounded by environment not suitable for the "island species"
253
What factors determine numbers on a island?
- the rate at which a new species migrate to it
| - the rate at which they become extinct on the island
254
What happens as the number of species on the island increases? and why?
the immigration rate of the new species deceases because any individuals reaching the island are less likely to represent a species that is not already present
255
why do extinction rate on the island increase?
due to increased competition
256
What is relative abundance ?
number on an organism compared with others in a community
257
What are the 4 main categories of threats to biodiversity?
- overexploitation (over harvesting)
- habitat loss
- introduced species
- global change
258
What is overexploitation?
the harvesting of natural resources
259
What does overexploitation involve?
the resources being harvested at a rate faster than they can be replaced
260
Give two types of overexploitation:
- overhunting
| - overfishing
261
What does the loss of genetic diversity cause?
the reduction of a population to below a level that is unlikely to recover
262
What is the "bottleneck effect"?
when a small population lose the genetic variation necessary to enable evolutionary responses to environmental change
263
What does inbreeding in small populations result in?
poor reproductive rates
264
What is the single greatest threat to biodiversity?
human alteration of habitats
265
What does the process of fragmentation of a habitat result in?
the formation of several habitat fragments whose total surface area is less than that of the original habitat
266
What is habitat fragment?
a small area of isolated habitat resulting from fragmentation
267
What does degradation of the edges lead to?
a proportionate decrease in size of the fragment and further loss of habitat
268
What is a possible solution to habitat fragmentation?
to link isolated fragments with habitat corridors
269
What is a habitat corridor?
a narrow strip of land to connect the disconnected fragments
270
What do habitat corridors allow?
allow species to feed, mate and recolonize habitat after local extinctions
271
What is a benefit of habitat corridors on biodiversity?
it provides access to other areas of habitat to increase gene flow and provides a route for species to reach the same food source
272
What are the problems with multiple corridor options?
- can be dominated by "edge" effects
- can increase the risk of parasitism
- can increase the spread of disease
- can facilitate the dispersal of invasive species
273
what are introduced species?
species that humans have moved intentionally or accidentally from the species native locations to new geographic regions
274
What are the benefits of introduced species?
- free from predators, parasites and pathogens that limit their populations in their native habitats
275
Definition of naturalised:
lives and breeds in the wild in its new habitat/ecosystem
276
What are invasive species?
naturalised species that spread rapidly and eliminate native species
277
When does hybridisation occur?
when members of two different species mate with one another and produce viable offspring
278
What are the two contributing factors to anthropogenic climate changes?
- the burning of fossils has increased levels of CO2
| - the felling of trees which reduces the number of plants photosynthesising
279
What are the 5 effects of climate change ?
- change in distribution and abundance of species
- change in timing of seasonal events
- changes in composition of plants and communities
- habitat loss
- increased sea temperature
