B15- Genetics and evolution Flashcards
Antibiotic resistance def?
Example of resistant disease?
When bacteria can’t be destroyed by the antibiotic
MRSA
Why can bacteria evolve quickly?
They reproduce quickly, so there is a greater chance of antibiotic-resistant bacteria mutations
How does antibiotic resistance occur and its affect on humans?
-Mutation occurs during division in DNA of a bacterium, resulting in antibiotic resistance
-This bacterium is not affected when antibiotic is taken
-No competition for growth so it reproduces, passes on resistant gene
-Population of resistant bacteria increases, more likely for humans to be infected and they are not immune to it
4 ways to prevent antibiotic resistance
-Finish the course of antibiotics
-Use the correct type of for the bacteria
-Only prescribe when needed (not for viral)
-Restrict agriculture use of antibiotics
3 problems with the development of new antibiotics
-Costly
-Slow
-Unlikely to keep up with new resistant strands
Classification def?
Also called?
Placing organisms into groups based on their shared features
Taxonomy
Who grouped organisms based on their similarities?
Why was this no longer up to date?
Carl Linnaeus
Microscopes proved observable similarities to be too simple
Original 7 taxa from Linnaeus?
Kingdom, phylum, class, order, family, genus, species
First 5 kingdoms?
Later changes to these kingdoms?
Plants, animals, protista, fungi, prokaryotes
Plants, animals, protista, fungi, archaebacteria, eubacteria
Species def?
A group of organisms that can be bred together to produce fertile offspring
Rules when writing scientific names/ binomials
First name?
Second name?
Final rule?
Name of the genus with capital letter
Name of species with lower case letter
Both names underlined when hand written
Domains
Key fact?
3 types?
Above the kingdom, came after Linnaeus
Bacteria, archaea, eukaryota
What kingdoms fall under the domains:
Bacteria?
Eukaryota?
Archaea?
Bacteria- Eubacteria
Eukaryota- Protista, fungi, plants, animals
Archaea- Archaebacteria
What organisms are found in the domains:
Bacteria?
Eukaryota?
Archaea?
Bacteria- true bacteria, prokaryote
Eukaryota- contain nucleus w genetic material
Archaea- primitive forms of bacteria, including extremophiles
1st stage of genetic history
Who investigated pea plants?
What was his key observation?
Gregor Mendel
The inheritance of each characteristic is determined by ‘units’ that are passed on to offspring
2nd stage of genetic history
What did microscopes allow to be observed?
The behaviour of chromosomes during cell division
3rd stage of genetic history
How did Mendel’s ‘units’ help?
Chromosomes and his ‘units’ behaved in similar ways. ‘Units’ were then called genes
4th stage of genetic history
Final discoveries?
Structure of DNA and mechanism of gene function
3 main ideas of Darwin’s theory of evolution
-Organisms in a species show variation for each characteristic
-Organisms w variations more suited to the environment are more likely to survive and breed
-Their variations are passed on to the next generation
2 main ideas of Lamarck’s theory of evolution
-Organisms developed certain traits over their lives to help them survive
-Useful changes in its life would be passed onto offspring
2 reasons why Darwin’s theory wasn’t accepted
-Challenged the idea that God made Earth
-Insufficient evidence of genes
1 Reason why Lamarck’s theory wasn’t accepted
-Visible that traits acquired in lifetime aren’t passed down e.g muscles
What did Alfred Wallace do?
-Proposed the theory of evolution alongside Darwin
Species
A group of similar organisms able to breed together and produce fertile offspring
What is speciation and how does it happen?
-Variation exists within a population
-Part of a population of species can be isolated
-Natural selection occurs in each population
-Ideal characteristics will be different to original environment, different alleles are passed on
-Eventually characteristics change so much they can’t interbreed to produce fertile offspring
2 ways that populations become isolated?
Explanation and example?
Geographical isolation- caused by a geographical feature e.g rivers, volcanoes
Environmental isolation- changes in climate e.g warmer in one area than another
Fossil def?
The preserved remains or traces of a dead organism
3 ways that fossils can be formed
-An organism not decaying after it dies due to the conditions needed for decay not being present.
-When hard parts of the organisms are replaced by minerals as they decay
-Traces left behind being preserved e.g footprints and droppings
Steps for the formation of a fossil?
-Organism dies
-Buried in sediment
-Soft parts decay
-A condition for decay is missing
-The bones are replaced by minerals
4 conditions for decay
-Oxygen
-Water
-Temperature
-Bacteria
3 reasons for gaps in fossil records
-Some fossils could be buried deeper and not found yet
-Destruction of fossils due to geological activity
-Oldest organisms were soft-bodied so most parts decayed
Extinction def?
The disappearance of a species either globally or locally
3 biotic causes of extinction
New predators- can wipe out prey quickly
New diseases
New competitors/more successful competitors- can out compete original species for food
2 environmental causes of extinction
-Gradual changes to the environment e.g ice age
-Single catastrophic events e.g volcanic eruptions
Mass extinction
Def?
1 Ad & dis?
When most of the species on Earth died
Allows evolution of new species
Loss of biodiversity
