Evolution: Natural selection

Charles Darwin was born on the 12th of February 1809 and died on the 19th April 1882, He   did

• Not suggest the theory of evolution
• He suggested the idea of natural selection
• He spent 5 years on HMS beagle
• Saw variation between individuals of the same species, found on the Galapagos Islands

His observations

1. offspring were similar to parents
2. no two organisms are identical
3. organisms may produce many offspring
4. populations in nature tend to remain stable in size

Therefore Variation is key to a species ability to survive.

 

 

Darwin’s finches

His conclusions

• there is a struggle to survive
• better adapted individuals survive and pass on their characteristics
• over time, a number of changes will give rise to a new species that would not be able to interbreed successfully

Natural selection is the selection by the environment of particular individuals that show certain variations, these individuals will survive to reproduce and pass on their variation to the next generation

 

 

English: Charles Darwin (1809-1882) in his later years. This image is flipped. Darwin’s mole was on the right side of his nose. (Photo credit: Wikipedia)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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Selection Pressure drives natural selection

• availability of food
• predators
• disease
• physical and chemical factors

The sequence of events leading to natural selection include

1. there is competition within a population for resources that are limited
2. there is genetic variation within the population
3. some individuals possess a favorable characteristic which means that they are better adapted to the environment
4. individuals with the favorable characteristics will have more offspring than the individuals with the less favorable characteristics
5. The possessors of the favorable characteristic will pass the favorable characteristics on to some of their offspring
6. this is repeated over many generations and natural selection occurs

Speciation is the formation of a new species from an existing one

 

• long, slow accumulation of changes over many generations
• eventually species can no longer interbreed

Speciation requires a reproductive or geographical barrier to stop some organisms within a group are unable to interbreed,

• beneficial changes spread down generations
• these changes can end up affecting part of a group
• this isolated group can becomes different from the others
• eventually so different that they become a new species

Geographical separation (allopatric speciation)

• prevents interbreeding between populations on different islands
• speciation likely to occur
• This permitted new species

Reproductive Barriers Cause Sympatric Speciation

A reproductive barrier is any factor that prevents reproduction between the species, there are 3 main types of reproductive barrier

1. Biochemical changes prevents fertilization
2. behavioral change prevents mating
3. physical change prevents intercourse

Developing effective operations with quality

Quality is the features of a product or service that are designed to satisfy the customer.

measures of quality include

• appearance
• measure
• functions
• after sales service
• image and brand
• exclusivity

Quality systems are approaches used by organisations in order to achieve quality. Most are classfied under two headings, quality control and quality assurance

So what are the benefits of having a quality control system?

• impact on sales volume: If the product or service meets the needs of customers, then demand for these products will increase
• Creating a unique selling point: Businesses can use the level of their quality as a USP in order to increase demand
• Impact on selling price: Having a USP would allow the business to charge a higher price
• Price flexibility: having a high level of quality allows a business to be flexible with their pricing decisions in order to target different market segments
• cost reductions: A quality system can reduce costs by improving production methods and reducing waste and the number of faulty products
• The firms reputation: A good quality system can prevent problems and help a business to avoid any damage to its repuatation

Apple Imacs, have a USP from their High quality designs to the well run operating system OSX

There are some issues with a quality control system

• costs- quality procedures require a great deal of administrative expense to set up
• training: can be expensive and extensive
• disruption of production: in the short run, training can cause disruption to the production methods currently taking place

Quality Control vs Quality Assurance

Quality Control

• inspection at the end of production
• prevent a defective product reaching a customer, therefore reducing  the problem with a whole bunch of products
• it is more secure than a system that relies on one individual
• it may detect common problems throughout the organisation

Quality assurance

• ownership of the production rests with the production opereratives, rather than with an independant inspector
• it can have a positive effect on motivation, due to a sense of ownership
• less need for reworking faulty products
• better quality first time, which results in less crap
• it provides cost savings helps to ensure consistent product quality

The main mehod of quality assurance is usually total quality managment, which occurs when there is a culture of quality throughout the organisation. It is based on the philisophy of “right first time” so if the individual who makes the product ensures quality, then there is no need for inspection.

ISO 9001

This is an internationally recognzied  quality standard, to achieve this, firms must ensure that they have thw uality systems to cover the quality of their working methods, services and processes as well as the quality of their products, the focus is on preventation or rapid detection of faulty products, ensuring that adequate support systems are in place and good team working exists, the benefits of this award are:

• marketing advantages from the acknowledgment of higher quality standards
• assurance to customers that the products meet certain standards
• greater employee motivation from the sense of recognition and responsibility
• financial benefits in the long term from the reduction in waste and the improved repuation of the firm.

Evolution: Adaptation

So what will a well adapted organism be able to do?

• find food and photosynthesise
• find enough water
• gather enough nutrients
• defend itself from predators and disease
• survive in all conditions of its environment
• respond to changes in environment
• have enough energy to reproduce

Behavioural adaptation: aspects of behaviour that permit survival

anatomical: Structural adaptations

Physiological: ensures the correct functioning of cell processes

EXAMPLE OF ADAPTATION: Xerophytic plants

Behavioural adaptations include:

• close stomata when little water is available
• fold or roll leaves
• some open stomata so water does leave, the leaves shrink so reducing the surface area

Physiological adaptations:

• plants absorbs water when its available and it fills the cells for years

anatomical adaptations:

• roots spread over large area
• long roots down
• small surface area for evaporation
• waxy leaves
• sunken stomata
  

  Cacti are good examples of Xerophytic plants)

Evolution: Variation

variation is the presence of variety

• variation within a species
• variation between a species

Examples of human variation can include:

• eye colour
• hair colour
• skin colour
• nose shape

There are 2 types of variation within species, it is continuous and discontinuous
variation.

Continuous variation:

• 2 extremes to the variation
• fill range of values between those extremes
• most individuals are close to the mean value
• there are a few individuals at the extreme values
• tends to be quantitative
• controlled by a lot of genes
• strongly influenced by the environment

 

discontinuous variation

• is where the data has 2 or more distinct categories
• it is either one thing or another
• it is not in between and has no intermediate values
• the members of the species can be evenly distributed between the forms
• controlled by a few genes
• unaffected by the environment

 

Variation can be caused by the environment and genetics

we inherit genes. We have alleles for a characteristic, human cells contain approx 25,000 genes, many of these genes will have more than one allele. Environmental factors such as obesity in humans and a persons skin colour,height, direction of growth, amount of growth

 

Modern classification

English: Three-dimensional structure of cytochrome c (green) with a heme molecule coordinating a central Iron atom (orange). PDB id, 1HRC, Bushnell et al., “High-resolution three-dimensional structure of horse heart cytochrome c.” J Mol Biol. 1990 Jul 20;214(2):585-95. PubMed PMID: 2166170. (Photo credit: Wikipedia)

Biochemistry

There are large biochemical molecules found in all living things but they may not be identical. We can study the different molecules and determine the evolutionary relationships. For example Cytochrome C is a protein that is used in respiration so all organisms require it. However Cytochrome C varies between species.

So if you looked at Cytochrome C from 2 different species, you can compare the amino acids in the polypeptide.

• If the sequence of amino acids are the same, then the species must be closely related
• if the sequence of amino acids are not the same, then the species may not be closely related
• the more different the sequence of amino acids, in species are, the less closely related are the 2 species

Comparing a DNA sequence

• All living things will contain code for building protein
• you can therefore compare DNA sequence to classify species
• the more similar the sequence, the more closely related the 2 species
• We can compare DNA sequences to clarify or correct previous assumptions

So how were the 3 domains determined

• Eubacteria are very different from Archaea and Eukaryotes

Bacteria differ from eukaryotes:

• different flagella and enzymes
• no proteins located on genetic material
• different method of DNA replication

Both Archaea and Eukaryotes share:

• similar enzymes to build DNA (RN
  A polymerase
• similar method of DNA replication
• both proteins bound to DNA

Budgets and the importance of Cash flow

A budget is an agreed plan establishing in numerical or financial terms the policy to be persued and the possible outcome of that policy. There are 3 types of budget that is often used by businesses….

• Income budget: Is the planned income into the business over a period of time
• Expenditure Budget: is the planned expenditure by a business over a period of time
• Profit Budget: Is the planned minimum amount of profit made by a business over a period of time

There are benefits and draw-backs of using budgets, these include

Benefits of budgets

• to establish priorites and to indicate the level of importance attached to a particular policy or division
• to provide direction and coordination and ensure that the spending is geared towards the firms aims
• to assign responsibility by identifying the person who is resonsible for the success/failure
• To motivate employees by giving them targets to work towards so they would greater responsibility and recognition when they meet their targets
• to improve efficiency by investigating the reasons for failiure and success
• to encourage forward planning by studying possible outcomes

Drawbacks of using Budgets

• a budget that is set to generously may encourage inefficiency, this will demotivate staff and hinder progress through a lack of money
• external factors outside the budget holders control may affect their ability to stick to a plan
• poor communication can be a problem as it would mean that people would not understand each other or the area in question and also other factors that might influence the budgets

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Budgetary control is important to the business as it is the establishement of the budget and the continuous comparisons of actual  and budgeted results in order to ascertain variances from the plan and to provide a basis for revision of the objective or strategy. A Variance is the difference between th planned budget and the actual budget. If the variance is poor, such as higher fixed costs or lower sales, then it as an adverse variance. Whereas if the budget is good, such as higher sales and lower fixed costs, then it is known as a favourable variance. By identifying what type of variance it is, it can allow a business to identify responsibility and take appropriate action. If its an adverse variance, then providing the factor that caused the adverse variance is under the firms control- they can then consider taking alternative approaches. Favourable variances can be used to identify efficient methods that can be adopted elsewhere in the company.

Variances can be caused by changes in-

• storage and wastage of material
• quality of material
• cost of material
• morale and efficiency of staff
• effiiciency changes
• wages

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Improving Cash flow

Cash flow management means that there is careful control of cash in theshort term in order to ensure liquidity. A business that is making losses will fail. But even a business that is profitable can still go out of business as they may have a poor cash flow, therefore would not have any cash to pay their creditors. My making a cash flow forecast it can also allow firms to identify possible problems and take the appropriate actions. Causes of cash-flow problems could include

• over investment in fixed assets, leaving no money to pay the bills
• overtrading by producing too many goods and running out of cash
• credit sales will worsen the cash flow as it would increase sales, increase the variable costs but you will not have the money to pay for it until a later date
• stockpiling means that you would have to many assets tied up in stocks
• changing tastes as products may no longer sell
• Management errors can mean that poor market research or budgetary errors can lead to cash shortages.

There are various ways of improving the cash flow of a business

Bank overdraft

Pros

• easy to organise
• flexible
• cheaper than a loan as interest is only paid on the amount overdrawn

cons

• as its flexible it maybe difficult to budget accurately
• the rate of interest charged is usually higher than the overdraft compared to a short term loan

Short term bank loan

• fixed interest rate, so simpler to budget
• rate of interest is usually less on the bank loan compared to an overdraft
• can be set up for a significant period of time so to suit the needs of the business

cons

• interest is paid on the whole of the sum borrowed, if the business can pay the loan earlier then a loan penalty maybe charged
• collateral will need to be provided

Debt factoring

• improved cash flow in the short term
• administration costs are lower because the factoring company chases any bad debts
• there is a reduced risk of bad debts

cons

• business will lose some revenue
• factoring company will charge more compared to a loan
• customers may prefer to deal directly with the business that sold them the product

sales of assets

• can raise alot of money
• getting rid of unused assets can reduce costs

cons

• can be hard to sell quickly
• fixed assets are used to produce goods that can be sold to create profit

sale and leaseback of assets

• overcome cash flow problem by providing an immediate inflow of money
• fixed costs can be reduced
• still have access to the asset

cons

• rent paid is likely to exceed the sum recieved, eventually
• firm owns fewer assets, so less collateral
• asset is gone when the lease ends

A firm could also improve their cash flow by…..

• diversifying its product portfolio
• anticipating change better
• setting aside a contigency fund
• controlling stock carefully to reduce the costs incurred in holding to much

Naming living things

 

 

Digitally improved version of Alexander Roslin’s painting of Carl von Linné. This particular version has had dust and missing specs of paint deleted. (Photo credit: Wikipedia)

 

 

The Binomal system was developed by Carl Linnaeus and uses 2 names (Genus and species in Latin), before this people had used a common name, but this was a problem because…..

• same organisms have different names in different parts of the country
• different common names are used in different countries
• translation of languages or dialects may give different names
• the same common name maybe used for different species in different parts of time world

Thats why Latin is used, it is a universal language, so whenever a species is given its name, it is given its universal name (in Latin) as to avoid confusion

Binomal is the GENUS and species= the first letter of the genus is always capital and the first letter of the species should always be lower case.

We can identify organisms using a Dichotomous Key, as it involves a series of questions with 2 alternative answers, usually yes or no, this leads you to the next question until you can identify the specimen. A good key will have fewer questions than the number of specimens