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Flashcards in Topic 4 Deck (92):

What is a species

a group of organisms with similar morphology, physiology and behaviour, which can interbreed to produce fertile offspring, and which are reproductively isolated from other species.


What is Biodiversity

The variety of plant and animal life in the world or a habitat


What is Endemism

Species in a defined geographical location and only that location


What is a Habitat

Place where an organism lives


What is a Population

Group of interbreeding species


What is a community

When there are various populations in a habitat


What is the heterozygosity index

H = number of heterozygotes /population


What are the equations used for measuring biodiversity

Heterozygosity index
Hardy-Weinberg Equation
The diversity index


What is a niche

How an organism exploits its environment and the precise role of an organism in its environment. In simple terms, an organism’s niche is where it lives and what it does there.


When are two species in competition with eachother

• If two species in a habitat that are not in competition they do not control the same niche
• If two species control the same niche they will be in competition, and the better adapted organism will win


How does adaptation link with competition

Organisms adapt to exploit niches better for a higher change to survive


There are three areas where adaptation can occur in a species what are they



What is behavioural adoptation

How the organism acts e.g leaves growing towards the sun, feeding times


What is Physiological adoptation

Internal workings of the organism


What is Anatomical adoptation

Physical characteristics e.g fluffy bumble bees = more pollen


What is co-adoptation

Two organisms become dependent on each other


How does natural selection take place

1. Naturally occurring mutation and genetic variation leads to new alleles
2. Change in environment causes the selection pressure to change
3. New allele becomes advantageous meaning the organism is more likely to survive and produce offspring
4. Offspring is more likely to inherit this allele and it therefore becomes more common in the population


How does natural selection effect a species

Changes from random mutations occur over generations and leads to evolution (the change in allele frequency in a population over time)


What is the purpose for the hardy weinberg equation

Looks for changes in allele frequency


What is the hardy weinberg equation and why does the equation = 1

p² + 2pq + q² = 1 (always equals 1 because there is only one allele)


What do all the symbols mean in the hardy weinberg equation and what does the answer represent

P² = The frequency of homozygous dominant allele
2pq = The frequency of heterozygous alleles
q² = The frequency of homozygous recessive alleles
Answer is a percentage (%) e.g 0.7 = 70%


What is speciation

When a new species is developed and is productively isolated


What is classification and what is it based off

• Organising the variety of life based on relationships between organisms
• Based off phenotypes which can be found using DNA analysis (e.g sharks and dolphins have no relation)
• Classification is used to look at evolutionary relationship


What does Taxonomy mean

The scientific study of putting organisms into hierarchical taxa (groups)


What is the hierarchy of groups

1. Phylum (classification according to body shape)
2. Class ()
3. Order ()
4. Family ()
5. Genus ()
6. Species (morphology, physiology, behaviour interbreed to produce fertile offspring and reproductively isolated)


How many kingdoms were there and what are they



What did the Animalia kingdom consist of

multicellular eukaryotes that are heterotrophs (have energy as readymade organic molecules by ingesting material from other organisms)


What did the Plantae kingdom consist of

multicellular eukaryotes that are autotrophs (make their own organic molecules by photosynthesis)


What did the Fungi kingdom consist of

multicellular eukaryotes that are heterotrophs but absorb their energy through decaying matter after external digestion


What did the Protoctista kingdom consist of

eukaryotes that photosynthesise or feed on organic matter from other sources but are not included in the other kingdoms, incused single celled protozoa such as algae


What did the Prokaryotae kingdom consist of

prokaryotic organisms, includes bacteria and blue-green bacteria


What does the scientific community do in the catagorisation of developing domains

• Community carefully checks data for reliable and valid results
• For archae Carl Woese found this category, but didn’t do shite to tell people about it as he was to shy to go to conferences


What are the three domains used today

Bacteria, Archaea and Eukaryota


What do modern evolutionary systems try to do

attempt to show evolutionary relationships between species


How is classifying helpful to medication

Looking for relationships between organisms that are already used in medication


What is used to measure genetic diversty

The Diversity index D=(N(N-1))/(∑n(n-1))


What is the name given for the number of species in a habitat

Species richness


What do all the symbols in the diversity index mean

D = diversity index
N = total number of organisms for all species
N = total number of organisms in each species


What is the structure of a plant cell

Large valcuole in the center
Around the vacluole:
vacuolar membrane
All the usual stuff Eukaryotes have
Amyloplast (contains starch grains)


What is cellulose

A polysaccharide, that is an important part of the cell wall.


What is the structure of cellulose

• Made of β-glucose
• Bonds from in condensation reaction forming 1,4 glyosidic bonds
• 1000 – 10000 glucose units to form a straight chain
• Hydrogen bonds on -OH groups with neighbouring chains to form microfibrils which are made of 60-70 cellulose molecules
• Hemicellulose and pectins are used to glue the microfibrils in place and create a matrix to reinforce the cell wall
• The microfibrils are laid down at different angles to make the wall stronger and more flexible


Why must plant cells be stiff

for mechanical support but must also still be allowed to transport substances


What are the two transport tubes in plant cells

Xylem and Phloem cells


What is the function of Sclerenchyma and what do they look like

Columbus of their fibres provide cell walls with support, are chisel shaped and contains lignin


What are xylem vessels used for

For water and minerals transport


What is the structure of a xylem vessel

Has stiff cell wall, is made of dead cells


What are Phloem tubes used for

Long tubes that transport organic solutes


What is the structure of Phloem tubes

Does not support the plants structure because it does not have stiff cell wals


How do xylem vessels form and explain the process

• Autolysis (cell contents is broken down) of cell content leaves a dead empty cell as a tube


How are the xylem vessels waterproof

cells have been lignified so they are waterproof


How is water transported in xylem vessels

• Diffusion gradient, as the plant transpires the cavity provides enough force to drag the water up
• This movement is called the cohesion-tension theory


How do xylem vessels transport water and give examples of ions transported

• Transports ions in this mass flow system
• Nitrate --> needed to produce amino acids
• Magnesium --> needed to make chlorophyll
• Calcium --> stunts growth due to cell wall structure and permeability


What is the epidermis

dermal tissue


What are the tree types of tissue plants have

Ground tissue
Vascular tissue


What is the Vascular tissue

contains the vascular bundle and sclerenchyma


What are the components in a cross section of a plant stem

Epidermis (contains stoma)
Collenchyma tissue
Parenchyma tissue that contains:
Vascular bundel that contains:
Phloem tube
Xylem vessel


Explain the cohesion-tension theory and how can it help the plant

• Water has strong bonds between its molecules that keeps it together
• Some molecules make bonds with the cell wall
• Temperature effects density of water so when plants are living under ice of a frozen lake they will not freeze as the ice will float to the top, and they are at a lower point where the temp is higher


What are most of the cells in a phloem cell

Degenerate (dont do anything)


What does translocation mean

Mass transport of organic molecules


What is the structure of phloem cells

Mostly a fluid space called the lumen


What components surround the phloem plants

Perforated walls are sieve plates
• Area between sieve plates is called the sieve tube element
• Next to the sieve cells are the companion cells, these perform the metabolic functions for the sieve cells


How do the phloem and xylem work together

• Sugars and aminos made in the leaf made for energy storage or growth are transported around the plant via the phloem vessels
• Mineral ions from root via the phloem into the xylem to be transported upwards, and then to the leaf via the phloem again
• Water travels up the xylem and then some travels back down in the phloem


What does Turgid mean

A cell is completely full, if a plant loses water it loses turgidity causing the plant to wilt


What are uses for plants

• Textiles
• Heavy metal absorption
• Biocomposites fibres are mixed with plastic to make it stronger than plastic alone (biodegradable and renewable)
• Bio fuels
• Drugs (comes later)


How are plant fibres extracted

Enzymes (sometimes from bacteria), or chemicals are used to dissolve or digest the plant material around the durable fibres


What are anitbacterials

Toxic chemicals that kill bacteria


Why do plants use antibacterials

toxic chemicals to defend themselves


What can humans use antibacterials for



What are the stages of drug trials and explain what happens in them

1. Pre-clinical testing:
• Lab studies on cells, animals and tissue culture to see whether it is effective
• Takes several years
• Animal trials make a base for human trials
2. Clinical trials – phase 1:
• Small group of volunteers given different doses
• Volunteers are normally healthy but can be sick
• Confirms if drug is absorbed, metabolised, distributed and excreted
• Different doses are monitored
3. Clinical trials – phase 2:
• A group of 100-300 volunteers with disease treated to look for drug effectiveness
4. Clinical trials – phase 3:
• Large group of patients 1000-3000 are divided into two groups
• One group is given a placebo, the other the real thing
• Neither patient or doctor knows who has the placebo or the drug (double-blind randomised controlled trial)
• Statistic results
5. After licensing:
• Data is continued to be collected for effectiveness and safety


How do bacteria reproduce

asexually in the process called binary fission


What is binary fission

DNA is replicated, cell contents is synthesised and cell divides into roughly two equal half’s


What conditions are needed for optimum bacterial growth

sufficient nutrients and O2, optimum temp and pH, no toxic waste build up


What are the stages of bacterial growth

1. Lag phase -> cells adjust to conditions
2. Log or exponential phase -> cells divide at fastest possible rate for the given conditions
3. Stationary phase -> limited growth due to a negative change in the conditions
4. Death or logarithmic decay phase -> number of cell deaths is greater then cell growth


Why are seeds importat

Because they:
• Holds a lot of starch (does not dissolve in water)
• Protects the plant embryo
• Aids in dispersal
• Provides nutrition for the new plant


What can starch be used for

Starch is used in adhesives, paint, textiles, plaster, insulator, conditioner, sun screen and anti-perspirants
supper absorbent


How can starch be made bigger and harder

When heated in water the starch is able to absorb water causing it to expand, once it cools it hardens


How is starch made into a super absprbant

if it is chemically cross linked, gelatinised (made into jelly) and then dried it enables the particles to take in lots of water when rehydrated


How is starch made into foam

Can from a plastic mass, with a water content of less than 10% gelatinisation occurs at temperatures way over waters boiling point, if the pressure is also raised a plastic mass forms, and with a quick release of the pressure the starch expands forming foam


What are vegetable oils used for

Making fuel


What are the problems preventing sustainability

• Burning fossil fuels contributes to global warming via the greenhouse effect
• Oil reserves will eventually run out
• Plastics from these fossil fuels produce non-biodegradable waste
• Conflict between weather crops should be used for fuel or food
• Using paper bags instead of plastic ones wont work cuz rain will delete them, so plant-based plastic bags can be used and they will still biodegrade
• Limited space --> land not suitable, needed for wildlife or water conservation, increasing human population, more costly to produce things using plants


What are zoos used for

Money, research, education and helping endangered species


What does In situ mean

on site


What does Ex situ mean

off site


What do captive breeding programs do

• Successfully breeding animals
• To increase the number of individuals of the species
• Maintain genetic diversity within the captive breeding population
• Reintroducing animals into the wild if possible


How can genetic variation be lost

Genetic drift
Inbreeding depression


What is genetic drift

In small populations some alleles may not be passed on to the offspring which leads to a decrease in genetic variation


What is inbreeding

In small populations the likelihood of inbreeding is higher, this will cause the frequency of homozygous genotypes to increase and heterozygous to decrease


What is inbreeding depression

When individuals inbreed the offspring is more likely to get homozygous recessive genotypes which often have harmful effects


How do zoos maintain genetic diversity

• Maintaining a large size of population is the best way to do this
• Keeping studbooks these holds the genetic history and location of all the captive animals in the zoo, these are used to plan which animals are to breed with each other and weather a new animal will need to be transferred into the zoo


Why was the millennium seed bank founded and what does it do

• Plants are threatened worldwide by habitat destruction, to combat this seed banks and botanic gardens have been made
• The MSB project is to conserve seed samples from threatened species of plants


What percentage of seeds does the millennium seed bank want to have by 2020

Aim is to have 25% of the worlds species by 2020


How are the seeds stored and maintained

• Seeds live twice as long for ever 1% reduction in moisture, and every 5°C reduction
• Once seeds have been verified they are cleaned dried and stored at -20°C
• A month after some seeds are tested to see if they germinate, after this the test is done every 10 years
• In germination falls bellow 75% all seeds are grown so new seeds can be collected and stored
• These seeds are used for research, habitat reintroduction and species reintroduction