B15(Genetics And Evolution) Flashcards
What was Mendel’s observation
The inheritance of each characteristic is determined by ‘units’ that are passed on unchanged to descendants
In the late 19th century behaviour of …
Chromosomes during cell division was observed
In the early 20th century it was observed that …
-Chromosomes and Mendel’s ‘units behaved in similar ways
-This led to the idea that the ‘units’ (genes) were located on the chromosomes
In the mid 20th century the structure of …
DNA was determined and the mechanism of gene function was worked out
What was Lamarck’s theory of evolution
-Changes that occur in an organism during its lifetime can be inherited
-All animals evolved from primitive worms
What was Charles Darwin’s theory of evolution
All living organisms have evolved from simpler life forms by natural selection
What was Darwin’s 1st main idea about evolution
The individual organism in a particular species tend to show a wide range of variation for each characteristic
What was Darwin’s 2nd main idea about evolution
-Reproduction always gives more offspring than the environment can support
-The organism that have inherited the characteristics most suited to the environment are more likely to survive and breed successfully
What was Darwin’s 3rd main idea about evolution
When they breed they pass on the characteristics that have enabled them to survive to the next generation
Why was Darwin’s theory of evolution by natural selection gradually accepted
-conflict with the widely held belief that God made all the animals and plants on Earth
-Insufficient evidence
-no mechanism for explaining variation and inheritance
How do new species arise
-isolation: when 2 populations of a species becomes separated
-genetic variation between the populations
-natural selection that operates differently on the 2 populations
-speciation: where the populations become so different that successful interbreeding is no longer possible
Fossils are the …
Remains of organisms from millions of years ago that can found in rocks,ice and other places
What is the process of fossilisation
-The organism dies
-It gets buried under rock or mud
-The organism does not completely decay
-Minerals replace the hard parts of the organism
-This prevents exposure to oxygen
-this creates a fossil
When do fossils form
-hard parts of the animal or plant are replaced by minerals
-the organism doesn’t decay because it is too cold or it is too dry
-the bacteria that make things decay die because there is not enough oxygen
What is extinction
The permanent loss of all the members of a species
What are the factors that can cause extinction
-new predators
-new diseases
-more successful competitors
-catastrophic events
-environmental and geological changes
Bacteria can evolve rapidly because…
They reproduce at a fast rate
Mutations of bacterial pathogens produce…
New strains
How do antibiotic resistant bacteria form
-some strains might be resistant to antibiotics and so they are not killed
-they survive and reproduce so the population of the resistant strain increases by natural selection
-the resistant strain will then spread because people are not immune to it
MRSA is resistant to …
Antibiotics
To reduce the rate of development of antibiotic resistant strains doctors need to …
-Not prescribe antibiotics inappropriately
-patients use the correct antibiotics prescribed
-patients complete each course of antibiotics
The development of new antibiotics is …
Costly and slow and is unlikely to keep up with the emergence of new resistant strains
Studying the similarities and differences between organisms allows us to …
Classify them into archaea, bacteria and eukaryota
What is an Archaea
Primitive forms of bacteria that include the extremophyles organisms
What are kingdoms
Groups that Contain lots of organisms with many differences but a few important similarities
What is the kingdom of Archaea
Archaebacteria
What is the kingdom of bacteria
Eubacteria
What are the kingdoms of eukaryota
-the protista
-the fungi
-the plants
-the animals
What is the order to classify animals
