Biodiversity and Natural Resources Flashcards
(217 cards)
1
Q
How do plant cells differ from animal cells?
A
Plant cells contain most organelles that animal cells do, but also have additional structures like the cell wall, middle lamella, plasmodesmata, pits, chloroplasts, amyloplasts, vacuole, and tonoplast.
2
Q
What is the function of the cell wall?
A
Supports plant cells.
3
Q
What is the description of the cell wall?
A
A rigid structure that surrounds plant cells. It’s made mainly of the carbohydrate cellulose.
4
Q
What is the function of the middle lamella?
A
This layer acts as an
adhesive, sticking adjacent
plant cells together. It gives
the plant stability.
5
Q
What is the function of the Plasmodesmata? (single- plasmodesma)
A
Allow transport of substances and communication between cells.
5
Q
What is the description of the middle lamella?
A
The outermost layer of the cell.
6
Q
What is the description of the Plasmodesmata? (single- plasmodesma)
A
Channels in the cell walls that link adjacent cells together.
7
Q
What is the function of the pits?
A
Allow transport of
substances between cells.
8
Q
What is the description of the pits?
A
Regions of the cell wall where the wall is very thin. They’re arranged in pairs — the pit in one cell is lined up with the pit in the adjacent cell.
8
Q
What is the description of the chloroplast?
A
A small, flattened structure.
It’s surrounded by a double
membrane, and also has
membranes inside called
thylakoid membranes.
These membranes are stacked up in some parts of the chloroplast to form grana. Grana are linked together by lamellae — thin, flat pieces of thylakoid membrane.
8
Q
What is the function of the chloroplast?
A
The site where photosynthesis takes place. Some parts of photosynthesis happen in the grana, and other parts happen in the stroma (a thick fluid found in chloroplasts).
9
Q
What is the function of the amyloplast?
A
Storage of starch grains.
They also convert starch
back to glucose for release
when the plant requires it.
9
Q
What is the description of the Amyloplast?
A
A small organelle enclosed
by a membrane. They
contain starch granules.
10
Q
What is the description of the Vacuole and Tonoplast
A
The vacuole is a compartment surrounded by a membrane called the tonoplast.
10
Q
What are the three main tissue types in plant stems?
A
Xylem vessels, sclerenchyma fibres, and phloem tissue.
11
Q
What is the function of the Vacuole and Tonoplast
A
The vacuole contains the cell
sap, which is made up of water, enzymes, minerals and waste products. Vacuoles keep the cells turgid — this stops plants wilting. They’re also involved in the breakdown and isolation of unwanted chemicals in the cell.
The tonoplast controls what
enters and leaves the vacuole.
12
Q
What is the function of sclerenchyma fibres?
A
Provide support—they are not involved in transport.
12
Q
What is the function of xylem vessels?
A
Transport water and mineral ions up the plant and provide support.
12
Q
What are the structural characteristics of xylem vessels?
A
Long, tube-like structures formed from dead cells, joined end to end in bundles.
Longer than they are wide, with a hollow lumen (no cytoplasm) and no end walls.
Forms an uninterrupted tube for easy transport of water and minerals.
Walls are thickened with lignin, providing strength and support.
Water and mineral ions move in and out through pits in the walls where there’s no lignin.
13
Q
How is phloem tissue structured?
A
Made from cells arranged in tubes, but only used for transport (not support).
Contains sieve tube elements and companion cells.(explain these)
14
Q
What are the structural characteristics of sclerenchyma fibres?
A
Made of bundles of dead cells running vertically up the stem.
Longer than they are wide, with a hollow lumen but do have end walls.
Cell walls are thickened with lignin but do not contain pits.
Have more cellulose than other plant cells.
15
Q
What are sieve tube elements, and what do they do?
A
Living cells joined end to end, forming sieve tubes.
End walls form sieve plates with holes to allow solutes to pass.
Have no nucleus, a very thin layer of cytoplasm, and few organelles.
Cytoplasm of adjacent sieve tube elements is connected through sieve plates.
16
Q
Why do sieve tube elements need companion cells and why are they important?
A
Due to their lack of a nucleus and few organelles, sieve tube elements cannot survive on their own.
Each sieve tube element has a companion cell that carries out living functions for both itself and the sieve tube.
Companion cells provide energy for active transport of solutes.
17
Q
Where are xylem vessels, phloem tissue, and sclerenchyma fibres found in a plant?
A
They are found throughout the plant, but their position in the stem is most important. (look image)
18
What forms vascular bundles in the stem?
Xylem vessels and phloem tissue together form vascular bundles.
19
What is usually associated with vascular bundles?
Sclerenchyma fibres.
19
What is a transverse cross-section and draw?
A section cut at a right angle to the length of the structure.
19
What is a longitudinal cross-section draw?
A section cut along the length of the structure.
20
What is the main energy storage material in plants?
Starch.
21
How do plants store and use starch?
Amylose and Amylopectin.
22
Describe the structure and function of amylopectin.
It is a long, branched chain of α-glucose. The branches allow enzymes to break down the molecule easily, releasing glucose quickly.
22
is starch insoluble in water, and why is this beneficial?
It does not cause water to enter cells by osmosis, preventing cell swelling. This makes it ideal for storage.
23
What is the major component of cell walls in plants?
Cellulose.
24
What is cellulose made of?
Long, unbranched chains of β-glucose, joined by 1-4 glycosidic bonds. The glycosidic bonds are straight, so the cellulose chains are straight
25
How do hydrogen bonds contribute to cellulose structure?
Between 50 and 80 cellulose chains are linked together by hydrogen bonds to form strong microfibrils.
26
Describe the structure and function of amylose.
It is a long, unbranched chain of α-glucose with a coiled structure. This makes it compact and good for storage.
27
What function do cellulose net like microfibrils provide?
The strength of the microfibrils and their arrangement in the cell wall gives plant fibres strength
28
What makes plant fibres useful?
They are strong, making them ideal for ropes and fabrics.
28
What makes plant fibres strong?
The arrangement of cellulose
microfibrils in the cell wall
The secondary thickening of cell walls
28
What are plant fibres made of?
Long tubes of plant cells, such as sclerenchyma fibres and xylem vessels.
28
How does The arrangement of cellulose microfibrils in the cell wall make plant fibres strong?
The cell wall contains cellulose microfibrils in a
net-like arrangement.
The strength of the microfibrils and their arrangement
in the cell wall gives plant fibres strength.
29
How does The secondary thickening of cell walls make plant fibres strong?
When some structural plant cells (like sclerenchyma and xylem) have finished growing, they produce a secondary cell wall between the normal cell wall and the cell membrane.
The secondary cell wall is thicker than the normal cell wall and usually has more of a woody substance called lignin. The growth of a secondary cell wall is called secondary thickening.
Secondary thickening makes plant fibres even stronger.
30
core prac plant tissues
You can look at part of a plant stem under a light microscope and identify xylem vessels, sieve cells (phloem
tissue) and sclerenchyma fibres. You might be given a pre-prepared slide to look at or you could dissect the stem
and prepare a section of tissue yourself. If you’re dissecting the plant stem yourself, you can use this method:
1) 2) 3) 4) 5) Use a scalpel (or razor blade) to cut a cross‑section of the stem (transverse or longitudinal).
Cut the sections as thinly as possible — thin sections are better for viewing under a microscope.
Be careful when using sharp equipment — make sure you’re cutting away from yourself and that any blades are free from rust.
Use tweezers to gently place the cut sections in water until
you come to use them. This stops them from drying out.
Transfer each section to a dish containing a stain, e.g. toluidine blue O (TBO), and leave for one minute.
TBO stains lignin blue-green, so will let you see the positions of the xylem vessels and sclerenchyma
fibres. The phloem cells and the rest of the tissue should appear pinkish purple.
Rinse off the sections in water and mount each one onto a slide (see page 10).
Place your prepared slide under a microscope and adjust the microscope until you get a clear image of
your sample. Make a labelled drawing that shows the positions of the xylem vessels, phloem sieve tubes
and sclerenchyma fibres.
30
What is biodiversity, and what does it include?
Biodiversity is the variety of living organisms in an area.
It includes:
Species diversity: The number of different species and their abundance in an area.
Example: A woodland with plants, insects, birds, and mammals.
Genetic diversity: The variation of alleles within a species or population.
Example: Human blood type is determined by a gene with three different alleles.
31
What is a population in terms of biodiversity?
A population is a group of organisms of the same species living in a particular area.
32
What does endemism mean?
Endemism is when a species is unique to a single place and isn’t naturally found anywhere else.
Example: The giant tortoise is endemic to the Galápagos Islands—it is only found there.
33
How has natural selection influenced biodiversity over time?
Natural selection leads to adaptation and evolution, which has increased biodiversity over time.
34
What human activities are reducing biodiversity?
Human activities, such as farming and deforestation, reduce species diversity.
This causes biodiversity to decline over time.
35
Why is conservation needed to maintain biodiversity?
Conservation helps protect biodiversity from human impacts.
It is especially important for endemic species, as they are more vulnerable to extinction.
If their habitat is destroyed, they can’t migrate, so their population declines.
36
What are two ways to measure species diversity?
Species richness: Counting the number of different species in an area.
A higher number of species = greater species richness.
Limitation: It doesn’t show how abundant each species is.
Index of diversity: Counting both the number of species and the number of individuals in each species.
Uses a mathematical equation (see page 80).
Gives a more accurate measure of diversity.
36
Why is it important to measure species diversity?
It helps to compare different habitats.
It allows scientists to study how a habitat has changed over time.
36
What is a habitat?
A habitat is the place where an organism lives.
Examples: A rocky shore or a field.
37
Why is sampling used instead of counting all organisms?
Counting every organism in a habitat is too time-consuming.
Instead, a sample is taken, and estimates are made for the whole habitat.
38
What are the steps involved in sampling a habitat?
Choose an area to sample (a small section of the habitat).
Use random sampling to avoid bias.
Example: Divide the field into a grid and use a random number generator to select coordinates.
Count the number of individuals of each species in the sample area.
Plants → Use a quadrat (a frame placed on the ground).
Flying insects → Use a sweep net.
Ground insects → Use a pitfall trap (a small hole that insects can’t escape from).
Aquatic animals → Use a net.
Repeat the process—take multiple samples to improve accuracy.
Use the data to estimate:
The total number of individuals in the habitat.
The species richness (total number of species).
Use the same sampling technique when comparing different habitats.
39
What is diversity within a species?
The variety shown by individuals of the same species (or within a population).
This variation exists because individuals have different alleles (different versions of the same gene).
40
How does the number of alleles in a species affect genetic diversity?
The greater the variety of alleles, the greater the genetic diversity.
Example:
Humans have three alleles for blood group.
Gorillas have only one allele for blood group.
Humans show greater genetic diversity for blood group than gorillas.
41
What is genetic diversity?
Genetic diversity is the variety of alleles in the gene pool of a species (or population).
The gene pool is the complete set of alleles in a species (or population).
42
How can scientists investigate genetic diversity?
By investigating changes in genetic diversity over time.
By comparing genetic diversity between two populations of the same species.
43
What are the two ways to measure the genetic diversity of a species?
Phenotype – Observable characteristics of an organism.
Genotype – DNA sequence and allele differences.
44
How can phenotype be used to measure genetic diversity?
Phenotype refers to an organism’s observable characteristics.
Different alleles code for slightly different versions of the same characteristic.
By looking at different phenotypes in a population, you can estimate allele diversity.
More phenotypes = Greater genetic diversity.
Example:
Humans have different eye colours due to different alleles.
Northern Europe has a variety of blue, grey, green, and brown eyes.
Outside this area, brown eyes are most common = less genetic diversity.
45
How can genotype be used to measure genetic diversity?
DNA samples are taken and the sequence of base pairs is analysed.
The order of bases in different alleles is slightly different.
Example: The allele for brown hair has a different base sequence than the allele for blonde hair.
Sequencing DNA of individuals in a species allows comparison of alleles.
The more alleles a species has for a characteristic, the greater the genetic diversity.
The heterozygosity index can also be used to measure genetic diversity.
46
What is a heterozygote?
An individual with two different alleles at a particular locus (gene position on a chromosome).
47
What does the heterozygosity index measure?
It measures genetic diversity within a species
48
What does a higher proportion of heterozygotes indicate?
Greater genetic diversity in the population.
48
Formula for Heterozygosity Index (H)
Heterozygosity=Number of heterozygotes/number of individuals in the population
49
What is an index of diversity?
It measures species diversity by considering both:
Species richness (number of different species).
Abundance of each species (population sizes).
50
Formula for Index of Diversity (D)
D= N(N−1)/∑n(n−1)
N = Total number of organisms of all species
n = Total number of organisms of one species
Σ = Sum of n(n - 1) for each species
- Higher D value = Greater diversity
- If all individuals belong to the same species (no biodiversity), D = 1
51
What is a Niche?
A Niche is the Role of a Species Within Its Habitat
The niche a species occupies within its habitat includes:
Its interactions with other living organisms
Example: What it eats and what eats it.
Its interactions with the non-living environment
Example: The oxygen an organism breathes in and the carbon dioxide it breathes out.
52
Why is Every Niche Unique?
Each species has its own unique niche—only one species can occupy a specific niche.
It may seem like two species share the same niche, but there will always be slight differences.
Example: They may be eaten by the same predator but consume different prey.
If two species attempt to occupy the same niche, they will compete.
One species will be more successful, eventually leading to the exclusion of the other species.
52
Examples of animals with similar Niches
Common Pipistrelle Bat 🦇
Habitat: Farmland, open woodland, hedgerows, and urban areas in Britain.
Feeding: Catches insects while flying using echolocation.
Echolocation Frequency: Around 45 kHz.
Soprano Pipistrelle Bat 🦇
Habitat: Woodland areas near lakes or rivers in Britain.
Feeding: Catches insects while flying using echolocation.
Echolocation Frequency: Around 55 kHz.
52
What are behavioural adaptations?
Behavioural adaptations are ways an organism acts that help it survive or reproduce.
52
What are adaptations?
Adaptations are features that increase an organism’s chance of survival and reproduction. They can be behavioural, physiological, or anatomical (structural).
53
How do brown bears use a physiological adaptation to survive winter?
Brown bears hibernate, lowering their metabolism to conserve energy when food is scarce, increasing their chance of survival.
53
How do some bacteria use a physiological adaptation to survive?
Some bacteria produce antibiotics that kill other bacterial species, reducing competition and increasing their survival.
53
How do possums use a behavioural adaptation to survive?
Possums ‘play dead’ when threatened by predators. This helps them avoid being attacked, increasing their chance of surviva
54
How do scorpions use a behavioural adaptation for reproduction?
Scorpions perform a mating dance to attract a mate of the same species, increasing the likelihood of successful reproduction.
55
What are physiological adaptations?
Physiological adaptations are internal processes in an organism’s body that help it survive.
56
What are anatomical adaptations?
Anatomical (structural) adaptations are physical features of an organism that help it survive.
57
How do otters use an anatomical adaptation to survive?
Otters have a streamlined body shape, which helps them glide through water more easily, making it easier to catch prey and escape predators.
58
How do useful adaptations become more common in a population?
Through evolution by natural selection, where advantageous traits help individuals survive and reproduce, passing on beneficial alleles to future generations.
59
How do whales use an anatomical adaptation to survive?
Whales have a thick layer of blubber, which provides insulation to keep them warm in cold waters where their food is found.
60
How do mutations contribute to evolution?
Mutations introduce new alleles, creating variation in a population. Some alleles give individuals traits that improve their chances of survival.
61
What are selection pressures?
Selection pressures are factors that affect an organism’s chance of survival and reproduction, such as predation, disease, and competition.
62
What happens to individuals that lack advantageous alleles?
They are less likely to survive due to selection pressures, leading to fewer individuals and less competition for resources among those that remain.
63
What happens to individuals with advantageous adaptations?
They have a higher chance of survival, reproduce more, and pass on their advantageous alleles to their offspring.
64
How does natural selection lead to evolution over time?
Over generations, individuals with beneficial traits become more common, increasing the frequency of advantageous alleles in the population.
64
How does natural selection lead to evolution?
Natural selection favours beneficial traits, causing populations to change over generations as these traits become more widespread.
65
Who developed the original theory of evolution by natural selection?
Charles Darwin.
66
Why is Darwin’s theory widely accepted today?
Over time, more evidence has been found to support it, and no evidence has disproven it.
67
What increases scientists’ confidence in a theory?
The more evidence there is, the more likely it is to become an accepted scientific explanation.
68
What variation is seen in peppered moths?
There are light-coloured moths (with alleles for light colour) and dark-coloured moths (with alleles for dark colour due to mutations).
69
What happened to the environment during the 1800s that affected moth survival?
Pollution blackened many trees, making the dark moths better camouflaged from predators.
70
Why did the number of dark moths increase?
Light moths were more visible to predators, leading to fewer surviving and less competition for dark moths.
71
How did the dark moths become more common?
They were more likely to survive, reproduce, and pass on the alleles for dark colouring.
72
What happened to the population of moths over time?
The allele frequency for dark colour increased, making dark moths more common.
73
What defines a species?
A group of similar organisms that can reproduce to produce fertile offspring.
74
What is speciation?
The development of a new species due to reproductive isolation.
74
-
75
What are three ways reproductive isolation can happen?
Seasonal changes – different mating or flowering seasons.
Mechanical changes – changes in genitalia prevent mating.
Behavioural changes – differences in courtship rituals.
76
How can a population become reproductively isolated?
Through geographical isolation or random mutations that lead to changes in alleles and phenotypes that prevent succesful breeding
77
What is geographical isolation?
It happens when a physical barrier divides a population of a species, preventing interbreeding.
78
What are some examples of physical barriers that cause geographical isolation?
Floods, volcanic eruptions, and earthquakes can create barriers that separate parts of a population.
79
How do environmental conditions differ on either side of a geographical barrier, and why is this important?
Each side of the barrier may have a different climate, food sources, or predators, leading to different selection pressures that influence which traits are advantageous in each population.
80
How does natural selection contribute to the development of different traits in geographically isolated populations?
Since the environment on each side of the barrier is different, natural selection favors different traits, causing populations to evolve in distinct ways over time.
80
What happens to conditions on either side of the physical barrier?
They will be slightly different, such as having different climates.
81
How do changes in allele frequencies affect the physical characteristics of a population?
As allele frequencies shift, certain phenotypes (observable traits) become more common in each population, allowing them to better survive in their specific environment.
81
What happens to allele frequencies in a population that has been geographically isolated?
Allele frequencies change independently in each population. If a certain allele provides a survival advantage in one environment, its frequency will increase in that population.
82
How do mutations contribute to speciation in geographically isolated populations?
Mutations occur independently in each population, leading to new genetic variations. These mutations can change allele frequencies and contribute to the divergence of populations.
83
How does reproductive isolation lead to the development of a new species?
When two populations can no longer produce fertile offspring due to genetic differences, they are reproductively isolated and are considered separate species.
83
What does it mean for two populations to become genetically distinct, and why does this happen?
Over time, genetic differences accumulate to the point where the two populations can no longer interbreed successfully. This means they have become genetically distinct.
83
What is evolution in terms of allele frequency?
Evolution is the change in the allele frequency of a population over time.
84
How are new alleles typically generated in a population?
New alleles are usually generated by mutations in genes.
84
What is a population
A population is a group of organisms of the same species living in a particular area.
84
What is the allele frequency?
The allele frequency is how often an allele occurs in a population. It’s usually given as a percentage of the total population (e.g., 35%) or as a number (e.g., 0.35).
84
What are the four major steps in geographical isolation leading to speciation?
A physical barrier divides a population, preventing interbreeding.
Populations on each side adapt to their specific environment.
Different alleles become more common due to selection pressures.
The two populations become so different that they can no longer interbreed, forming separate species.
85
What does the Hardy-Weinberg principle predict about allele frequencies?
The Hardy-Weinberg principle predicts that the frequencies of alleles in a population won’t change from one generation to the next, but only under certain conditions.
85
Under what conditions does the Hardy-Weinberg principle hold true?
The Hardy-Weinberg principle holds true under the following conditions:
A large population.
No immigration or emigration.
No mutations or natural selection.
Random mating, where all possible genotypes can breed with all others.
85
What can Hardy-Weinberg equations be used for?
Hardy-Weinberg equations can be used to calculate the allele frequencies in a population and see if the population is changing over time.
86
: What does it mean if the allele frequencies change between generations in a large population?
If the allele frequencies change between generations, it suggests that immigration, emigration, natural selection, or mutations have occurred.
86
What is the Hardy-Weinberg equation used to calculate allele frequency?
p + q = 1
Where:
p = frequency of the dominant allele
q = frequency of the recessive allele.
86
What is a genotype?
The genotype of an organism is the combination of alleles it has.
87
What does the Hardy-Weinberg equation p + q = 1 represent?
This equation represents the total frequency of all possible alleles for a characteristic in a population, which must equal 1.0. The frequencies of the dominant and recessive alleles must add up to 1.0.
87
What is the Hardy-Weinberg equation for calculating genotype and phenotype frequencies?
The equation for calculating genotype and phenotype frequencies is:
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.
87
How can you calculate the frequency of one allele if you know the frequency of the other allele?
You can calculate the frequency of one allele using the equation p + q = 1, and rearranging it. For example, if the frequency of the dominant allele (p) is 0.4, the frequency of the recessive allele (q) would be:
q = 1 – p,
So, q = 1 – 0.4 = 0.6.
88
How do genotype frequencies add up in the Hardy-Weinberg equation?
The total frequency of all possible genotypes for a characteristic in a population must equal 1.0, meaning that the frequencies of the homozygous dominant, heterozygous, and homozygous recessive genotypes must add up to 1.
89
How can you calculate the frequency of a genotype if you know the frequencies of the others?
You can calculate the frequency of a genotype by using the Hardy-Weinberg equation. For example, if the frequency of genotype RR (p²) is 0.34 and the frequency of genotype Rr (2pq) is 0.27, the frequency of genotype rr (q²) would be:
q² = 1 – p² – 2pq,
So, q² = 1 – 0.34 – 0.27 = 0.39.
89
How do you calculate phenotype frequencies from genotype frequencies?
Phenotype frequencies can be calculated by adding the frequencies of the genotypes associated with a particular phenotype.
For example, if the frequency of genotype RR is 0.34 and Rr is 0.27, the frequency of red flowers (the dominant phenotype) would be 0.34 + 0.27 = 0.61, and the frequency of white flowers (the recessive phenotype) would be 0.39 (from rr).
90
How do you estimate the percentage of cystic fibrosis carriers in a population if the frequency of cystic fibrosis (ff) is 1 in 2500?
To estimate the percentage of cystic fibrosis carriers (Ff), use the Hardy-Weinberg equations:
p + q = 1 (The sum of the frequencies of the dominant and recessive alleles must equal 1)
p² + 2pq + q² = 1 (The sum of the frequencies of all genotypes must equal 1)
Step-by-step calculation:
Calculate q² (frequency of homozygous recessive ff):
q² = 1 ÷ 2500 = 0.0004
Find q by taking the square root of q²:
q = √0.0004 = 0.02
Calculate p using p + q = 1:
p = 1 - 0.02 = 0.98
Calculate 2pq to find the carrier frequency (Ff):
2pq = 2 × 0.98 × 0.02 = 0.039
The percentage of cystic fibrosis carriers (Ff) is 3.9%.
91
What makes a species endangered, and why is this important for conservation efforts?
Endangered species are those at risk of extinction due to:
A low population or
A threatened habitat.
These species need protection to ensure their survival and to maintain biodiversity.
91
How can you track changes in allele frequencies over time using Hardy-Weinberg equations if the frequency of cystic fibrosis (ff) was 1 in 2500 and has changed to 1 in 3500 after 50 years?
You can use Hardy-Weinberg equations to monitor allele frequency changes. If the allele frequency changes, it suggests external factors like natural selection, immigration, emigration, or mutations have affected the population.
Step-by-step calculation:
Initial condition (50 years ago):
Frequency of cystic fibrosis (ff) = 1 in 2500.
q² = 1 ÷ 2500 = 0.0004
q = √0.0004 = 0.02
After 50 years, the new frequency of cystic fibrosis (ff) = 1 in 3500:
q² = 1 ÷ 3500 = 0.00029
q = √0.00029 = 0.017
The change in q from 0.02 to 0.017 indicates that the population's allele frequency has shifted, which suggests that Hardy-Weinberg equilibrium has been disrupted, likely due to factors like immigration, emigration, or natural selection.
91
How do zoos and seedbanks contribute to the conservation of endangered species?
Zoos help conserve endangered species by:
Breeding them in captivity.
Educating the public about conservation.
Sometimes reintroducing them into the wild.
Seedbanks conserve genetic diversity by storing seeds from endangered plants, preserving them for future restoration or replanting efforts.
92
What are the main tasks involved in the work of seedbanks?
The main tasks in seedbanks include creating cool, dry conditions for storage, testing seeds for viability (ability to grow into a plant), and replanting, growing, and harvesting new seeds for future storage.
92
What is biodiversity, and why is it important for global ecosystems?
Biodiversity refers to the variety of organisms in an area.
The extinction of species or the loss of genetic diversity within species leads to a reduction in global biodiversity.
A decrease in biodiversity can harm ecosystems, making them less resilient to environmental changes and disruptions.
93
How do seedbanks help conserve genetic diversity?
Seedbanks help conserve genetic diversity by storing seeds from plants with different characteristics, such as tall and short sunflowers. This includes preserving different alleles within plant species.
93
What is the role of seedbanks in conserving biodiversity and how do they store seeds?
A seedbank is a store that holds seeds from a variety of plant species. They help conserve biodiversity by storing seeds of endangered plants. If these plants become extinct in the wild, the stored seeds can be used to grow new plants.
94
What are some advantages of using seedbanks for plant conservation?
Advantages of seedbanks include:
It's cheaper to store seeds than fully grown plants.
Seedbanks can store larger numbers of seeds than plants because they need less space.
Less labor is required to look after seeds compared to plants.
Seeds can be stored anywhere as long as it's cool and dry, unlike plants which require specific conditions.
Seeds are less likely to be damaged by disease, natural disaster, or vandalism than plants.
95
What is the purpose of captive breeding programmes in zoos?
Captive breeding programmes involve breeding animals in controlled environments to help increase the numbers of endangered species or species that are already extinct in the wild. For example, pandas are bred in captivity because their numbers are critically low in the wild.
95
What are some disadvantages of using seedbanks for plant conservation?
Disadvantages of seedbanks include:
Testing the seeds for viability can be expensive and time-consuming.
It would be too expensive to store all types of seeds and regularly test them for viability.
Collecting seeds may be difficult for some plants, especially those that grow in remote locations.
95
Why do some people oppose captive breeding programmes, even when they aim to prevent extinction?
Many people think it’s cruel to keep animals in captivity, even if the purpose is to prevent them from becoming extinct
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What are some challenges with captive breeding programmes?
Animals can have difficulty breeding outside their natural habitat, which can be hard to recreate in a zoo.
Some species, like pandas, do not reproduce as successfully in captivity as they do in the wild.
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How can the reintroduction of organisms from zoos and seedbanks help conserve species?
The reintroduction of plants grown from seedbanks or animals bred in zoos can increase their numbers in the wild, helping to conserve their population or bring them back from the brink of extinction. It can also help organisms that rely on these plants or animals for food or as part of their habitat.
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How does reintroducing organisms contribute to habitat restoration?
The reintroduction of plants and animals helps restore habitats that have been lost, such as rainforests that have been cut down.
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What are some potential problems with reintroducing organisms to the wild?
Reintroduced organisms could bring new diseases to habitats, harming other organisms.
Reintroduced animals may not behave as they would if raised in the wild, such as having difficulty finding food or communicating with wild members of their species.
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What is an example of successful reintroduction of a species?
The Californian condor was nearly extinct in the wild, with only 22 birds left. Thanks to captive breeding programmes, there are now around 300 condors, half of which have been successfully reintroduced to the wild.
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How do seedbanks contribute to scientific research?
Scientists can study how plant species can be successfully grown from seeds, which is useful for reintroducing them to the wild. Seedbanks can also be used to grow endangered plants for use in medical research, new crops, or materials, preventing the need to remove plants from the wild.
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What is a disadvantage of studying plants in seedbanks for scientific research?
Studying plants from seeds in a seedbank limits the data to small, interbred populations, meaning the information may not be representative of wild plants.
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How do zoos contribute to scientific research?
Research in zoos increases knowledge about the behaviour, physiology, and nutritional needs of animals, which can contribute to conservation efforts in the wild. Zoos can also carry out research that’s not possible for some species in the wild, such as nutritional or reproductive studies.
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What is a disadvantage of conducting research on animals in zoos?
Animals in captivity may act differently than those in the wild, which can affect the accuracy and applicability of the research.
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How do zoos help educate people about conserving biodiversity?
Zoos let people get close to organisms, increasing their enthusiasm for conservation work, and raising public awareness about endangered species and reduced biodiversity.
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How do seedbanks contribute to educating people about biodiversity conservation?
Seedbanks contribute to education by providing training and setting up local seedbanks around the world. The Millennium Seed Bank Project, for example, aims to conserve seeds in their original country.
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What are renewable resources?
Renewable resources are resources that can be used indefinitely without running out, such as plants. Harvested plants can be regrown, ensuring there will be plenty for future generations.
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What is sustainability?
Sustainability is using resources in a way that meets the needs of the present generation without compromising the ability of future generations to meet their own needs, meaning resources aren't depleted.
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Why are fossil fuels not considered renewable resources?
Fossil fuels (e.g., petrol) are not renewable because once they are used up, there is no more left.
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What is an example of a sustainable practice?
Replacing trees after logging is an example of a sustainable practice. When a tree is cut down, a new one is planted in its place, ensuring the process can repeat without significantly damaging the environment.
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Why can unsustainable practices not continue indefinitely?
Unsustainable practices can't continue because the resources would eventually run out, which would negatively impact future generations.
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What is an example of an unsustainable practice?
The use of fossil fuels to make oil-based plastics like polythene is an example of an unsustainable practice because the resources used are non-renewable.
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What is a sustainable alternative to making ropes and fabrics from plastic?
Ropes and fabrics can be made from plant fibers, which is more sustainable than using oil-based plastic. Plant fibers use less fossil fuel and can be regrown to maintain the supply for future generations.
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What is a disadvantage of making ropes from plant fibers?
Ropes made from plant fibers are generally not as strong as ropes made from plastic.
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Why are products made from plant fibers considered more environmentally friendly than plastic products?
Products made from plant fibers are biodegradable and can be broken down by microbes, unlike most oil-based plastics that remain in the environment for many years.
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Why are plant fibers cheaper to process compared to oil-based products?
Plants are easier to grow and process to extract the fibers than oil, making them cheaper to produce and easier to process in developing countries due to less technology and expertise needed.
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What is starch, and in which crops is it found?
Starch is found in all plants, with crops such as potatoes and corn being particularly rich in starch.
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What are bioplastics, and why are they more sustainable than oil-based plastics?
Bioplastics are plastics made from plant-based materials like starch. They are more sustainable than oil-based plastics because they use less fossil fuel and the crops can be regrown.
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What is bioethanol, and why is it more sustainable than fuel made from oil?
Bioethanol is a fuel made from starch. It is more sustainable than oil-based fuel because it uses less fossil fuel, and the crops from which the starch comes can be regrown.
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Why do plants need water?
Plants need water for photosynthesis, to transport minerals, to maintain structural rigidity (water exerts pressure in cell vacuoles), and to regulate temperature (water evaporating from leaves helps cool the plant down).
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What is the role of magnesium ions in plants?
Magnesium ions are needed for the production of chlorophyll, the pigment required for photosynthesis.
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Why are nitrate ions important for plants?
Nitrate ions are needed for the production of DNA, proteins (including enzymes), and chlorophyll. They are essential for plant growth, fruit production, and seed production.
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What role do calcium ions play in plants?
Calcium ions are important components of plant cell walls and are required for plant growth.
116
How do temperature and pH affect bacterial growth?
If the temperature or pH is too high or too low, it can affect enzyme activity, disrupting metabolic processes like respiration, which prevents bacteria from growing and reproducing normally.
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What do bacteria need to grow and reproduce?
Bacteria need a source of nutrients for respiration and growth, oxygen if they rely on aerobic respiration, and suitable temperature and pH conditions for enzyme activity to function properly.
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What happens to a plant if there isn’t enough water or inorganic ions in the soil?
If there isn't enough water or inorganic ions, the plant will show deficiency symptoms like stunted growth.
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Why is it important to use aseptic techniques in microbial investigations?
Aseptic techniques prevent contamination from unwanted microorganisms, ensuring the culture grows as expected and avoiding contamination with human pathogens.
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What are some examples of aseptic techniques?
Examples include closing windows and doors to avoid drafts, disinfecting surfaces, working near a Bunsen flame, sterilising the wire inoculation loop, flaming the neck of glass containers, and sterilising all glassware in an autoclave.
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How do you sterilise the wire inoculation loop in aseptic techniques?
The wire inoculation loop should be sterilised by passing it through a hot Bunsen burner flame for 5 seconds before and after each use to kill any microbes on the loop.
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Why is it necessary to flame the neck of a glass container after opening and before closing?
Flaming the neck of the container prevents contamination by causing air to move out of the container, which stops unwanted organisms from falling in.
123
How was drug testing done in the past, and how did William Withering contribute to it?
In the past, drug testing was much less scientific and often dangerous, relying more on trial and error. William Withering, a scientist in the 1700s, discovered that an extract from foxgloves could treat dropsy (swelling caused by heart failure). He made this discovery after a patient recovered using a traditional remedy containing foxgloves. Withering knew foxgloves were poisonous, so he began experimenting with different concentrations of the active compound, digitalis, which he called his "digitalis soup." Through trial and error, Withering found that too much digitalis poisoned patients, while too little had no effect. This process helped him determine the right dosage for treating patients.
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What happens in Phase 1 of clinical drug testing?
In Phase 1, a new drug is tested on a small group of healthy individuals to determine the safe dosage, potential side effects, and how the body reacts to the drug. This phase helps ensure the drug is safe for further testing.
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What is the process of modern drug testing?
Modern drug testing follows a more controlled protocol. First, computers are used to model potential effects of a drug. Then, the drug is tested on human tissues in a lab, followed by testing on live animals before clinical trials on humans. Clinical trials have three phases:
Phase 1: Testing on a small group of healthy individuals to determine safe dosage, side effects, and how the body reacts to the drug.
Phase 2: Testing on a larger group of patients to assess the drug's effectiveness.
Phase 3: Comparing the drug to existing treatments on hundreds or thousands of patients.
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What is tested in Phase 2 of clinical trials?
In Phase 2, the drug is tested on a larger group of patients to see how well it works for treating the condition it is intended for. This phase helps determine the effectiveness of the drug.
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What occurs in Phase 3 of clinical trials?
Phase 3 involves comparing the new drug to existing treatments by testing it on hundreds or thousands of patients. It helps determine if the new drug is more effective or has fewer side effects than current treatments.
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Why is using a large sample size important in clinical trials?
Using a large sample size makes the results of clinical trials more reliable by reducing the impact of outliers and providing a more accurate picture of how the drug performs in different people.
129
What is a placebo, and why is it used in clinical trials?
A placebo is an inactive substance that looks like the real drug but doesn't have any effect. It is used in clinical trials to compare the effects of the new drug against no treatment, helping researchers see if the drug actually works or if improvements are due to the placebo effect (where patients believe they're receiving treatment and show improvements).
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How does the double-blind study design help clinical trials?
In a double-blind study, neither the patients nor the doctors know who is receiving the new drug or the placebo. This reduces bias because neither group can influence the results, ensuring that the findings are based solely on the drug's effects.
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What is taxonomy?
Taxonomy is the science of classification, involving the naming and organizing of organisms into groups based on their similarities and differences.
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What are the eight levels of classification hierarchy?
Domain → Kingdom → Phylum → Class → Order → Family → Genus → Species.
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What is a species in biological classification?
A species is the most specific classification group, containing only one type of organism that can breed together to produce fertile offspring.
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What is the binomial naming system?
It is a two-word scientific naming system where the first word is the genus and the second word is the species name (e.g., Homo sapiens for humans).
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How do scientists classify organisms today?
Classification is based on phenotypes, genotypes, and how related organisms are.
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Q: Why is taxonomy useful?
It makes it easier for scientists to identify and study organisms.
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How many taxonomic levels are there in classification?
Eight levels.
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What are the three largest classification groups?
Domains: Eukaryota, Bacteria, and Archaea.
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What do the two parts of a scientific name represent?
First word = Genus name
Second word = Species name
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Why is the binomial naming system important?
It minimizes confusion by allowing all scientists to call a species by the same name worldwide.
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What three factors are used to classify organisms?
Phenotypes, genotypes, and how closely related organisms are.
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How did early classification systems classify organisms?
Based only on observable phenotypes (physical features).
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How has DNA sequencing affected classification?
New technologies allow scientists to analyze genotypes, leading to new discoveries and reclassification of species.
Example: Skunks were originally classified with weasels and badgers in the Mustelidae family but were later reclassified into the Mephitidae family due to significant DNA differences.
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What are the five kingdoms?
Prokaryotae (Monera) – Bacteria
Protoctista – Algae, protozoa
Fungi – Moulds, yeasts, mushrooms
Plantae – Mosses, ferns, flowering plants
Animalia – Insects, fish, reptiles, mammals
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What are the characteristics of Prokaryotae?
Prokaryotic, unicellular, no nucleus, very small (<5 µm).
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What are the characteristics of Protoctista?
Eukaryotic, mostly unicellular, live in water.
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What are the characteristics of Fungi?
Eukaryotic, chitin cell wall, saprotrophic (absorb dead organic matter).
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What are the characteristics of Plantae?
Eukaryotic, multicellular, cellulose cell wall, autotrophic (photosynthesis).<
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What are the characteristics of Animalia?
Eukaryotic, multicellular, no cell wall, heterotrophic (consume other organisms).
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Why must new scientific data be evaluated?
To ensure experiments were designed properly and conclusions are fair.
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How can new scientific data influence classification?
It can change the way a species is classified, leading to organisms being reclassified or modifications in the classification system structure.
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How do scientists share new classification discoveries?
Through meetings and scientific journals.
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What happens if scientists generally agree with new data?
It can lead to an organism being reclassified or changes in classification system structure.
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What does the tentative nature of scientific knowledge mean?
Classification systems change over time based on new scientific discoveries.
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What is an example of new scientific data leading to a classification change?
The introduction of the three-domain system, replacing the five-kingdom system.
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What new data led to the three-domain system?
Molecular phylogeny, which uses DNA and protein molecules to determine how closely related organisms are.
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What is phylogeny?
The study of the evolutionary history of groups of organisms.
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What does phylogeny help scientists determine?
Which species are related and how closely related they are.
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How does molecular phylogeny classify organisms?
By analyzing their DNA and protein molecules, since more closely related organisms share more similar molecules.
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How does the older five-kingdom system classify organisms?
All organisms are placed into one of five kingdoms.
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How does the newer three-domain system classify organisms?
All organisms are placed into one of three large domains, which are above kingdoms in the taxonomic hierarchy.
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What are the three domains in the modern classification system?
Bacteria, Archaea, and Eukaryota
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How were Prokaryotes (Prokaryotae) reclassified?
They were split into two domains:
Bacteria
Archaea (previously grouped with bacteria but found to be more distantly related).
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What organisms are classified under the domain Eukaryota?
Organisms from the other four kingdoms (Fungi, Plantae, Animalia, Protista), which all have cells with a nucleus.
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Why were the Prokaryotae split into two domains?
Molecular phylogeny showed that bacteria and archaea were more distantly related than originally thought.
