7 - Genetics And Ecosytems Flashcards
1
Q
Habitat definition
A
The place where an organism lives
2
Q
Population definition
A
All the organisms of one species in a habitat
3
Q
Community definition
A
Populations of different species in a habitat make up a community
4
Q
Ecosystem definitions
A
A community, plus all the non living conditions in the area in which it lives
5
Q
Abiotic definition
A
The non living features of the ecosystem
6
Q
Biotic definition
A
The living features of the ecosystem
7
Q
Niche definition
A
The role of a species within its habitat
8
Q
Adaptations definition
A
A feature that memebrane of a species have that increases their chance of survival amd reproduction
9
Q
The niche a species occupies within a habitat includes what 2 things
A
It’s biotic interactions
It’s abiotic interactions
10
Q
T or f
A niche can only be occupied by one species
A
T
11
Q
What will happen if two species try to occupy the same niche
A
They will compete until one is more successful
12
Q
What 3 ways can adaptations be
A
Physiological
Behavioral
Anatomical
13
Q
What is a physiological adaptation
A
Process inside their body
14
Q
What is a Behavioral adaptation
A
The way an organism acts
15
Q
What is an anatomical adaptation
A
Structural features of the body
16
Q
Describe natural selection
A
Organism with better adaptations are more likely to survive, reproduce and pass on the alleles for their adaptations , so the adaptations become more common in the population
17
Q
Every species is adapted to use an ecosystem in ….
A
It’s won unique way
18
Q
Are organisms only adapted to abiotic conditions
A
No they also adapt to biotic conditions
19
Q
Give an example of how otters adapt to abiotic conditions
A
They have webbed paws, so they can walk on land and swim effectively
20
Q
Give an example of how seals adapt to abiotic conditions
A
Thick layer of blubber, keep them warm in cold seas and increase chance of survival because they can live in places where food is plentiful
21
Q
Give an example of how hedgehogs adapt to abiotic conditions
A
Lower their rate of metabolism over winter. This increases their chance of survival as they can conserve energy during there coldest months
22
Q
Give an example of how otters adapt to biotic conditions
A
use rocks to smash open shellfish and clams
Increase serval chances as gives them access to another source of food
23
Q
What is a population size
A
The total number of organisms of one species in a habitat
24
Q
What is carrying capacity
A
The maximum stable population size of a species that an ecosyetm can support
25
Does carrying capacity varie due to abiotic or biotic factors
Both
26
How does abiotic factors effect carrying capacity
+eg
When they are idea for a species ( eg, light, water , space available, tempers are, chemical composition) organisms can grow fast and reproduce successfully
Eg. When the temperature of a mammals surroundings is the urea temperature for metabolic reactions to take place, they don’t have to use as much energy maintains their body temp.mso a lot of energy can use for growth and reproducing, so population size will increase
27
What is interspecific competition
+eg
When organisms of differnt species compete with each other for the same resources
Eg. Red and grey squirrels compete for the same food source and habitat in the uk
28
What does interspecific competition cause
Competition between Two species can mean that the resources available to both populations are reduced
So both populations will be limited by a lower amounts of food, so they will have less energy for growth and reproduction, so population sizes will be lower for both species
29
What will happen if two species are competing but one is better adapted that the other to its surroundings
The less adapted species is likely to be out competed
30
What is intraspecific competition
When organisms of the same species compete with each other for the same resources
31
Explain how species population varies by intraspecific competition
The population of a species increases when recorded are plentiful. As th population increases theeell be more organism competing for the same amount of space and food
Eventually resources such as food and space become limiting- there isn’t enough for all the organism. The populations then begins to decline
A smaller population then means there there’s less completion for space and food, which is better for growth and reproductions - so the population. Starts to grow again
32
What is predation
Where an organism kills and eats other organisms
33
The population sizes of predators and prey are….
Interlinked
34
Explain how prey and predators populations sizes are interlinked
Prey pop increases, so more food for predators, so predators pop grows
As Predator pop increases more prey is eatean so prey pop falls
As prey pop falls there’s less food fro predators so they pop reduces and so on
35
How’d do other factors effect predator prey relations
It’s thought that the population of a species initially declines because there’s too many of them for the amount od food available. This is then accelerated by predation for the predator
36
What is succession
The process by which an ecosystem changes over time
37
What are the two types of succession
Primary
Secondary
38
When does primary succession occur
This happens on land that’s been newly formed or exposed
Eg. Where a volcano has erupted to form a new rock surface or where sea
Level dropped exposing new land .
No soil or organic material to start with
39
Where does secondary succession happen
On land that’s been cleared of all the plants but soil remains
Eg, a forest fire
40
Describe primary succession
1) abiotic conditions are hostile (no soil), pioneer species grow
2) pioneer species change the abiotic conditions - they die and miccrogansums decompose the dead organic materal ( humus). Forms soil
3) makes conditions less hostile eg. Soil holds water. New organisms move in and outcompete and become the dominant species
4) some new species may chmage the environment so that it becomes less suitable for the previous species
5) ecosystem becomes more complex , biodiversity increases
6) reaches a climax community,
41
What is a climax community
The ecosystem is supported the largest and most complex communities of plants and animals. It’s stable
42
What does which species that make up the climax communities depend on
What the climate is like in an ecosystem
43
The climate community for a particular climate is called…
Climatic climax
44
Give an example of a climatic climate
Polar climate - there’s not much avalaible water , temps are low and there are massive changes between the seasons . Larger trees won’t ever be able to grow in these conditions, so the climatic climax contains only herbs and shrubs but it’s still the climax community
45
When succession is stopped artificially , what is the climax community called
Plagioclimax
46
Give an example of human activity’s preventing succession
Regularly mown grassy fields worn develeop shrubs and trees even if climate do the ecosystem could support the, the growing points of the plants are cut of by the lawnmower so larger plants can’t establish themselves
47
What is conservation
The protection and managements of ecosystems
48
What does conservation sometimes involve (in terms of succession)
Preventing succession in order to preserve an ecosystem in its current stage of succession.
Eg. Moorland in Scotland that provide habitats for many spaces of plants and animals. If moorland left to natural processes suchcceion would lead to the climax community of spruce forest. So loss of moorland habitat and could leave to the loss of some plants and anaimks that currently live there
49
What are another 2 wats to manage succession to conserve the Moreland ecosystem
1)animals are allowed to graze on the land, this is similar to mowing - animals eat growing points of the shrubs and trees, which stops them establishing themselves
2) mamaned fires are lit. After fires secondary succession will occur on the moorland- the species that grow back first are the species that are being conserved. Larger species will take longer to grow back and will be removed again the next time the moor is burnt
50
What is conservation
The protection and management of species and habitats in a sustaible way
51
What does sustaible mean
Enough resources are taken to meet needs of people today , without reducing the ability of people in the future to meet their own needs
52
Give 4 examples of conservation techniques
1) plants can be conserved using seed banks, if a plant become extinct in the wild, the stored seeds can be used to grow new plants
2) finishing quotas are limits to amounts of certain fish species that fisherman are allowed to catch, they help conserve fish species by rescuing the numbers that are cuaght and killed
3) protected areas such as national parks and nature reserves protect habitats, restricts urban development, industrial development and farming
4) endangered species can be bred in captivity to increase numbers then returned to the wild
53
Page 178- evaluating conservation
54
How should you sample an area
Samples should be random to avoid bias
(Eg, grid and random number generator)
Repeat to reduce Likleyhood that your results are down to chance
55
How can the number of individuals of a whole area by estimated from a sample
Take a mean of the data in each sample and multiply to account for the size of the whole area
56
What is a non motile organism and how are they investigated
Ones that don’t move
Use quadrants and transects (these can also be used on slow moving organisms)
57
What is species frequency when using a quadrat
The number of individuals of each species
58
Apart form species frequency what else can a quadrat be used to measure
Percentage cover
59
What is a transect used for
To help find out how plants are distributed across an area
60
What is a belt transect
Quadrants are placed next to each other along the transect to work out species frequency and percentage cover along the transect
To cover a larger distance, quadrats can be placed at intervals along the line
61
What is it called when a belt transect us used but the quadrats are placed at intervals along the line
Interrupted belt transect
62
What is used to measure the abundance of more motile species
Mark release recapture
63
How to carry out mark-release-recapture
1) capture a sample of species using an appropriate technique, count the,
2) mark them in a harmless way eg. Paint
3) release them, back to the habitat
4) wait a week them take a second sample form the same population
5) count how many of the second Sample are marked, then use the equation to estimate total population size
64
What is the equation to estimate total population size during mark release recapture
total pop size = number caught in first sample. X number caught in 2nd sample
——————————————————————————————-
Number marked in the second sample
65
What assumptions are you making during mark release recapture
1) the marked sample has had enough time and opportunity to mix back in with the population
2) the marking hasn’t effected the individuals chances of survival, and the marking itself is still visible
3) there are no changes in population size due to birth death and migration during the period of study
66
How could you investigate the effect of an environmental factor on the distribution of species
(Eg, soil og on marram grass)
1) take measure as a transect for, shore to inland
2) 1m2 quadrats divided into 100 squares
3) place quadrat next to tape measure (ensure u place the quadrat the same way relative to the tape measure each time )
4) count the squares containing marram grass and record results as percentage cover
5) at each sample point measure ph
6) repeate every 10 m along transect
67
How do you measure ph of soil
Digital PH probe
Or
Take a sample and use a sieve to remove debris- test tube, add barium sulfate, distilled water ph indicator shake and leave to settle
Check colour against a ph chart
68
Why does PH decreases as you move inland on the beach
Near shore lots of shell fragments which are made of calcium carbonate ,( alkaline), and Inland rotting vegetation adds organic matter wich is more acidic
69
What could you do to mitigate risks of fieldwork at the beach
Read tide times
Suitable clothing and footwear
Wash hands
70
What are some ethical issues surrounding fieldwork
All fieldwork affects the environment where it’s carried out
Eg . Lots of people walking over grass
Plan to have the smallest impact (eg, restrict where they walk)
71
What is the null hypothesis
No significant differnce
72
What is the alternative hypothesis
There is significant differnce
(Any diff is not due to chance)
73
How do you work out the degrees of freedom
Number of catagories - 1
74
What is the chi squared test
A statistical test that’s used to see if the results of an experiment support a theory
75
What is the theory that is used to predict a result in the chi squared test
The expected result
76
The experiment is carried out and the actual result is recorded, what is this in the chi squared test
Observed result
77
What does the chi squared test do
Compare observed and expected results
The outcome either supports or rejects the null hypothesis
78
You can never prove that a null hypothesis is true, but what can you do
Reject or accept null hypothesis
79
What is the critical value
The value of chi squared that corresponds to a 0.05 level of probability that the differnce between the observed and expected value is due to chance
80
What does the chi squared test do
Finds out if there is a significant differnce between the observed and expected results
81
If your chi squared results are larger than or equal to the critical value then….
There is a significant differnce between observed and expected results
Null hypothesis is rejected
82
What are the 3 types of sampling
Quadrat
Transect
Mark release recapture
83
Quadrats and transects are used for ….
Non mobile organisms
84
What is a quadrats used
Estimate population numbers in an area
You can extrapolate the data for the whole habitat
You can record number of individuals or % cover
85
T or f
Quadrat use random sampling
T
86
What is a transect used for
Shows distribution along an environment gradient
87
What type of sampling is a transect
Systematic
88
What are the 2 types of transects.
Belt transect ( places a quadrat )
Point transect (records what’s on the line)
89
How are mobile organisms investigated
Mark release recapture
90
How to carry out mark release recapture with pitfall traps
animals are captured, eg using pitfall traps
they are counted and marked in a harmless, inconspicuous way and then released
traps are used again a few days later to recapture a sample of animals
the numbers of marked and unmarked animals caught in the traps are recorded
91
What are the conditions for using students t tests
The data must be continuous and normally distributed
The variance of the populations should be equal
The samples must be independent of each other
92
What is variation
The difference that exist between individuals
93
Variation within a species means ……
Individuals in a population can show a wide range of different phenotypes
94
What causes genetic variation within species
Although they have the same genes they have different alleals
95
What is the main source of genetic variation
Mutations
96
How is genetic variation introducers ( 4 )
Mutations
Crossing over
Independent segregation of chromosomes
Random fertilisation of gametes in sexual reproduction
97
Variation within a species can also be caused by differences in the …..
Environment
98
Most variation within a species is caused by combination of genetic and environmental factors, but which results in evolution
Genetic variation
99
What is evolution
The frequency of an allele in a population changes over time
100
Why do individuals of the same species vary
Different alleals
101
what is natural selection
Individuals vary, some are better adapted to the selection pressures than others
Thus means there are different levels of survival and reproductive sucesss in a population
Individuals with a phenotype that increases their chance of survival are more likeY to survive , reproduce and pass on their genes
So a greater proportion of the nect generation inherit the beneficial alleles
So frequency of the beneficial alleles in the gene pool increases from generation to generation
102
What are the three types of natural selection
Satbalising
Directional
Disruptive
103
What is stabilising selection
Where individuals with alleles for characteristics towards the middle of the range are more likely to survive and reproduce,
104
When does stabilising selection occur
it occurs when the environment isn’t changing and it reduces the range of possible phenotypes
105
What is directional selection
Where individuals with alleles for a single extreme phenotype are more likely to survive and reproduce. This could be in response to an environmental change
106
What is disruptive selection
Where individuals the alleles for extreme phenotype at either end of the range are more likely yo survive and reproduce.
107
When does disruptive selection occur
When the environment favours more than one phenotype
108
What is speciation
The development of new species from existing species
109
When does speciation occur
When populations of th same species become reproductively isolated - changes in allele frequency causes changes in phenotype, which mean they can no longer interbreed to produce fertile offspring
110
How could species become reproductively isolated
Physical barrier such as a flood or an earth quack divides a species causesimg some individuals to be separated from the main population
This is known as geographical isolation
Or
Without physical separation + known as sympatric speciation
111
What does geographical isolation lead to
Allopathic speciation
112
What does allopathic speciation require
Geographical isolation
113
Describe allopattric speciation
1) populations that are geographically separated will experience slightly different conditions
2) so populations experience different selection pressures and so different changed in allele frequencies
3) different alleles will be more advantageous in diff populations, allele frequencies also chmage as mutations occur independently in each pop ,genetic drift may also affect the allele frequencies in one or both populations
4) ch ages in allele frequencies will lead to differences accumulating in the gene pools of the separated population causing chmages in phenotype frequencies
5j eventually they won’t be able to breed with each other to produce fertile offspring - they will be reproducatubly isolated - two grouped become separated species
114
Describe sympatric speciation
Random mutation could occur within a population, preventing memebres of that populations breeding with other members of the species
115
Reproductive isolation occurs becuase changing in alleles and phenotypes in some individuals prevent that from breeding successfully
What does theses chmages inculde
Seasonal - individuals form the same population develope different flowering or mating seasons or become sexually active at differnt times of the year
Mechanical - changing in genitalia prevent successful mailing
Behavioral - a group of individuals develop courtship rituals that arnt attractive to the main population
116
What is genetic drift
Type of evolution
When chance, rather than environmental factors, dictate which individuals survive , breed and pass on their alleles
Ex.
Individuals within a population show variation in their genotypes, by chance the allele for one genome is passed on to the offspring more oftern than others, so number of individuals with that allele increases, changes in Alelelfrequency in two isolation populations could lead to reproductive isolation and speciation
117
T or f
Natural selection and genetic drift work alongside each other
T
118
Evolution by genetic drift usually had a greater effect in ………
Why
Smaller populations
Where chance has a greater influence. In larger population any chance variations in allele frequency tend to even out across the whole population
119
What causes ghe diversity of earth
Speciation and evolutions chmages
Started with one population, population was divided and new populations evolved into sperate species, new species divide again
120
INHERITANCE
121
Genotype
genetic constitution of an organism
122
Diploid
T he organism has 2 sets of chromosomes (
123
Haploid
The cell or organism has 1 set of chromosomes. Gametes have one set of chromosomes and some organisms have a stage in their life cycle where the cells have one set eg mosses
124
Dominant
Only one allele is needed for it to be expressed in the phenotype eg polydactyly
125
Recessive
two alleles are needed for them to be expressed in the phenotype eg cystic fibrosis
126
Codominant
both alleles are expressed in the phenotype eg red and white produces a roan cow
127
What does it mean that an allele is expressed
The allele is transcribed and translated and the protein it codes for produced
128
Locus
This is the location of a gene on a chromosome
129
Homozygous
The two alleles of a gene are the same
130
Heterozygous
The two alleles of a gene are differnt.
131
What is a mono hybrid cross
A genetic cross examining the inheritance of a single trait.
132
What is a punnet square
: A tool used to predict the genotypic and phenotypic ratios of offspring from a cross.
133
What is a phenotypic ratio
The expected ratios of different phenotypes in the offspring.
○ For a monohybrid cross involving a dominant and recessive allele, the typical phenotypic ratio is 3:1
(dominant : recessive).
134
Ff
Heterozygous
135
FF
homozygous dominant
136
ff
Homozygous recessive
137
In codominant alleles, is one reserve
No, they will express both phenotypes
138
Where is a sex linked gene found
on sex chromosomes
139
What differs between a Y and an X chromosome
A Y chromosome is shorter so many genes are missing
140
Therefore if the sex linked gene is found on the part of the X chromosome which does not have a homologous part on the Y chromosome…..
a male only needs ONE recessive allele for it to be expressed.
141
A heterozygous women for sex linked gene is called a
Carrier
142
a sex linked gene is always. Shown as……. To the sex chromosome tests
Sex linked
143
What is autosomal linkage
The phenomenon where two or more genes are located on the same autosome ( no sex chromosome) and are inherited together as they do not sort independently during meiosis
144
How many alleles of each gene does a gamete have
One
145
What is mono hybrid inheritance
The inheritance of a characteristic controlled by a single gene
146
What does a mono hybrid cross show
The likely hood of the different alleles of that gene being inhertied by offspring of certain parents
147
What are the 3 alleles for blood type
Io group O
IA group A
IB group B
148
Is Io recessive or dominant
Recessive
149
Does only one gene control a characteristic
No sometimes many genes that interact with
150
What is epistasis
When the allele of one gene masks the expression of the allele of other genes
151
What is different about crosses involving epistatic genes
They don’t result in the expected phenotypic ratios
152
What is the phenotypic ratio of a dihybrid cross involving a recessive epistatic allele
9:3:4
Dominant both : dominant epistatic restive other : recesssibe epistatic
153
Explain a dihybrid cross involving a recessive epistatic allele
Having two copies of the recessive epistatic allele masks the expression of the of the other gene.
154
What is the phenotypic ratio for a dihybrid cross involving a dominant epistatic allele
12:3:1
Dominant epistatic : recessive epistatic dominant other : recessive both
155
Explain dihybrid cross involving a dominant epistatic allele
having at least one copy of the dominant epistatic allele masks the expression of the other gene
156
Gene pool
The complete set of alleles within a popualtion
157
Genotype frequency
The proportion of individuals in a population with a specific genotype
158
Phenotypic variation
The observable differences in traits among individuals in a population.
159
Allele frequency
The proportion; of a specific allele in a gene pool
160
Genetic drift
Variations in allele frequencies in small populations due to chance
161
Genetic variation
Differences in genotypes between members of a population which may occur due to mutations meiosis or random fertilisation
162
What equation is used for allele frequency
(HW)
+ meanings
1. For allele frequencies:
p + q = 1
where:
○ p = frequency of the dominant allele
○ q = frequency of the recessive allele
163
What equation is used for genotype frequencies
(HW)
And meaning
2. For genotype frequencies:
p2+2pq+q2=1
where:
○ p2 = frequency of the homozygous dominant genotype
○ 2pq = frequency of the heterozygous genotype
○ q2= frequency of the homozygous recessive genotype
164
What are the conditions for hardy Weinberg to work
1. Large population size – Reduces the impact of genetic drift.
2. No mutations – No new alleles are introduced.
3. No natural selection – No allele has a selective advantage.
4. Random mating – Individuals pair by chance, not by phenotype or genotype.
5. No migration (gene flow) – No new individuals enter or leave the population.
165
What is bottleneck effect
A sharp reduction in population size due to a catastrophe, reducing genetic diversity
166
What is the founder effect
A small group of colonises a new area, leading to a less diverse gene pool
167
What is gene flow
Movement of alleles between populations
168
What is gene flow immigration
Introducing new alleals
169
What is gene flow emigration
Removal of alleles form the gene pool
170
What is how often an allele occurs in a population called
Allele frequ3ncy
171
What does hardy Weinberg principle predict
the frequency of alleles in a population won’t change form one generation ot the next ,
172
When is the hardy Weinberg principle only true
Large population
No immigration , emigration , mutations or natural selection
Also needs to be random mating
173
What can the hardy Weinberg equation be used to calculate
The frequency of particular alleles, genotypes or phenotypes
174
The hardy Weinberg equations can also be used to test for what?
Whether or not the hardy Weinberg principle applied to particular alleles in particular populations.
Such as testing for whether selection or any other factors are infuleing allele frequenci3z .
If frequencies do change between generations in a large population then there is an influence of soem kind
175
What is variation
Differences in characteristics among individuals of the same species
176
What 2 ways can variation arise
Genetic variation
Envorbpmental variaitpm
177
What are the 2 types of data
Continuous
Discontinuous
178
What is allopatric speciation
when two populations are separately geographically
179
What is sympatric speciation
When gene flow between two populations in the same area stop.
