B15 - Genetics and Evolution Flashcards
(27 cards)
Who proposed the theory of evolution?
Charles Darwin
What is the theory of evolution?
- Natural selection by his findings on the Galapagos where the different birds had different beaks dependant on how the food was supplied on each island
- 1859 - On the Origin of Species as book in whihc he published his ideas
Why was the theory of evolution only gradually accepted?
- The theory challenges the idea that God made all animals and plants
- Insufficient evidence and mechanism of inheritance was not known for another 50 years
What is the theory by Lamarck?
- Organisms changed throughout their lifetime and these traits were passed onto their offspring
- This is wrong because it’s survival of the fittest - those without the necessary traits to survive in their environment die and the ones that do have the traits survive to reproduce
What is Wallace best known for?
- Warning colouration in animals and his theory of speciation
- Worked worldwide gathering evidence for evolutionary theory
How does speciation occur
- Two populations of the same species become isolated from each other in different conditions, through natural selection in the species continues to evolve
- Different genes passed on from successful parent to offspring
- When the two populations come into contact again, they are genetically different and so are unable to interbreed successfully
What evidence do we have for evolution?
- Fossils and antibiotic resistance in bacteria
Why is Darwin’s theory for evolution now widely accepted?
- Has been shown how characteristics are passed on to offspring in genes, there is further fossil evidence and we have knowledge about antibiotic resistance in bacteria
What are fossils?
The remains of organisms from millions of years ago, found in rocks
How can fossil be made?
- From parts of animals have not decayed as conditions needed for decay are absent
- When parts of the organism are replaced by minerals as they decay
- Preserved traces of organisms, like footprints, burrowns and rootlet traces
Why is there little fossil evidence for early life forms?
- Early life forms were soft bodies which meant they left few traces
- Any traces have bee destroyed by geological activity
What can we learn from fossils?
- How much or how little organisms have changed as life developed on Earth
What is extinction?
- When there are no remaining individuals of a species still alive
What factors may contribute to the extinction of species?
- New predators
- New diseases
- New competitors
- Volcanic eruption
- Asteroids
- Loss of habitat
What are antibiotic resistant bacteria?
Bacteria that are not killed by antibiotics
How are antibiotic resistant bacteria created?
- Mutations of bacterial pathogens produce new strains
- Some strains may be resistant to antibiotics so aren’t killed
- Survive and reproduce so population of resistant strain rises
Why do resistant strain of bacteria spread?
People are not immune to it and there is no effective treatment
How can we reduce the development of antibiotic resistant strains?
- Not prescribe antibiotics inappropiately - e.g treating non-serious or viral infections
- Patients should complete their course of antibiotics so all bacteria are killed and none survive to mutate and form resistant strains
- Agricultural use of antibiotics should be restricted
Why are we unlikely to keep up with emergence of new resistant strains?
Development of new antibiotics is costly and slow
Who developed our traditional classification system?
- Carl Linnaeus
- Traditionally living things have been classified into groups depending on their structure and characteristics
How did Linnaeus classify living things?
- Kingdom
- Phylum
- Class
- Order
- Family
- Genus
- Species
How are organisms named?
- Named by the binomial system of genus and species
Why were new models of classification proposed?
- Evidence of internal structures became more developed due to improvements in microscopes and understanding of biochemical processes progressed
Who developed the three-domain system?
- Due to evidence available from chemical analysis
- Developed by Carl Woese
