What is selective Breeding?
The process by which humans breed plants and animals for particular genetic characteristics
What are the steps to genetically breed?
1) Choose 2 patents with the desired characteristics from a mixed population
2) Breed these 2 together
3) From the offspring, choose those with the desired characteristics and breed them together
4) Repeat this process over many generations until all offspring show the desired charachteristics
What is variation and what are the differences?
Differences in the characteristics of individuals in a population is called variation
These differences can be:
- The genes they have inherited (genetic causes)
- The conditions in which they have developed (environmental causes)
- A combination of genes and the environment
What is the human genome?
The genome of an organisms is the entire genetic material of that organism ( contains 21,000 genes)
What is DNA?
A chemical found in the nucleus of a cell. It is double stranded and a double helix molecule
Why would scientists study the human genome?
- To search for genes linked to types of diseases
- To understand and be able to treat inherited disorders
What is genetic screening?
Involves undergoing tests to discover person/embryonhas a gentic disorder or carrying a faulty allele
How can embryos be genetically tested?
It can be done by:
- Amniocentesis
- analysing foetal cells found in the mothers blood
What are the advantages for genetic testing?
- You can decide whether or not to have children or continue with the pregnancy
- Can plan ahead and get treatment for the condition (save money)
- They will know of there is a possibility of getting ill in the future
What are the disadvantages of getting genetically screened?
- Risk of miscarriage or harm to the mother or foetus
- Tests may not be 100% accurate
- screening is expensive
What is evolution ?
A change in the inherited characteristics of a population over time through a process of natural selection
What is a species?
A species is a group of similar organisms capable of interbreeding to produce fertile offspring
What are the advantages of selective breeding?
- It can produce animals and plants with desired characteristics
- It can increase production of milk/meat from cattle (increased profits for farmers
- Disease resistant crops produced
- Can produce domesticated animals with gentle nature so they can be kept as pets (eg. Labradoodle)
What are the disadvantages of selective breeding?
- May force anumals to inbreed due to the small pool of genes
- Ethical issues as they do not breed naturally
- Reduces variation
What is the definition of extinction?
Extinctions occur when there are no remaining individuals of species still alive
Name 5 causes of extinction
- Habitat destruction
- Diseases that cannot be cured
- Climate change
- Fishing and hunting
- Food chain
