CB4 Natural Selction Flashcards
Evolution
A gradual change in the characteristics of a species over time
Natural selection
The differential survival and reproduction of individuals due to differences in phenotype
Darwin’s theory
Members of a species show variation - some of this is genetic
Organisms which are features suited to their environment are more likely to survive and breed
These genes are passed down to the next generation
Mutations
A change in the sequence of genes
This can cause a rapid change in species
Bacteria and antibiotics natural selection
Antibiotics kill the less resistant bacteria
It’s an advantage to be resistant to antibiotics so the bacteria can survive longer
If the course of the antibiotics is not finished , the resistant bacteria reproduce again - pass on their advantageous characteristics
How does antibiotics provide evidence for evolution?
Makes the bacteria better adapted to an environment in which antibiotics is present. As a result, antibiotic resistance becomes common in the population over time.
Ardi
4.4mya
350cm brain volume
120cm height
Lucy
3.6-2.8 mya
400cm brain volume
107cm height
Homo habilis
2.4 - 1.4 mya
500-600cm brain volume
130cm height
Homo erectus
1.8- 0.5 mya
850cm brain volume
179cm height
What did Leakey discover?
Turkana boy - 1.6mya
Short arms, long legs, big brain size
Better at walking up right
Homo habilis - tools
Simple tools - pebble
Hitting rocks together to make sharp flakes
Scrape meat from bones or crack them
Homo erectus- tools
Sculpted rocks - hand axes
Hunt dig chop scrape bones
Homo neanderthalensis- tools
Complex tools
Flint , pointed and wooden spears
Homo sapiens
Flint tools
Arrow heads
Fish hooks
Needles
Methods to state the date of tools
Looking at structural features
Use stratigraphy - study of rock layers
Carbon 14 dating
Classification
Kingdoms
Grouped organisms based on their characteristics Animals Plants Fungi Bacteria Protoctists
What makes up the binomial name?
Genus and species - organisms that share the same genus are very similar
Bacteria - classification
No nucleus with all genes used for something
Eukarya
Nucleus with some unused dna present
Archaea
No nucleus with some unused dna present
Selective breeding
When humans artificially select which plants or animals are going to breed so that the genes for particular characteristics remain in the population.
Method for selective breeding
Select the ones from your existing stock which have the characteristics
Breed them
Select the best of the offspring , breed them
Continue to repeat
Benefits of selective breeding
Some cattle are better at producing meat
Improve meat yields
After doing this for a while - very high meat yield
Used for medical research
Drawbacks of selective breeding
Reduces the gene pool for a population - no variation
Lead to health problems - animals - ethical
If a disease occurs all the gm animals will be effected
Genetic engineering
The process of modifying an organisms genome to introduce desirable characteristics
Genetic engineering in agriculture
Crops are go to be resistant to herbicide
Farmers can spray crops to kill weeds without killing crops
Increases farmers yield
Disadvantages of genetic engineering agriculture
Gm genes may get out into the environment
Herbicide resistant gene may get picked up by weeds
Could effect food chains and human health
Genetic engineering - medicine
Transferred human genes that produce useful proteins into sheep and cows
Disadvantages of gm medicine
Can be hard to predict what effect modifying its genome will have on the organism
Animals suffer health problems
Genetic engineering insulin
Identify chromosomes Identify gene RE cut out gene RE cut open plasmid Stick gene to plasmid - DNA ligase and SE Insert plasmid into bacteria
