CB4: Natural Selection and Genetic Modification Flashcards
What is evolution?
change over time
Who came up with the idea of evolution by natural selection?
Charles Darwin
Who was Wallace?
An Australian man with similar ideas to Darwin at a similar time
What was Lamarkism?
the idea of evolution by acquired characteristics (animals change themselves). There’s no way to explain it.
What is Darwinism?
the idea that evolution occurs by natural selection - survival of the fittest (those who suit or adapt to suit conditions will survive). Evolution is so slow you wouldn’t notice it. Thought the Earth was around 3.8bn years old - not too far off the truth.
What is the tree of life?
The idea that all life comes from LUCA (last universal common ancestor)
What is LUCA?
the Last Universal Common Ancestor
What are the causes of extinction?
- competition
- environment
- diseases
- predators
What did Darwin observe?
- living things produce more offspring than end up surviving
- population sizes are mostly constant
- variation
- characteristics are passed on
phylogentic tree
“family tree” of evolution
Extant
living species
Extinct
dead species
fossil evidence -> archaeology
very old -> old
Closest relative to modern humans?
Homo Neanderthal/H. Neanderthal
Common ancestor with H. Neanderthal?
H. Erectus
What did H. Erectus evolve into in Europe, and what did they evolve into in Africa?
In Europe: H. Erectus -> H. Neanderthal
In Africa: H. Erectus -> H. Sapien
Archaeology
Remains with bones.
Helps to work out behaviours (eg: diet from stool)
What can teeth tell us?
what you ate
What can footprints tell us?
Behaviour - footprints in volcanic ash
What can brain size tell us?
brains were bigger, then they got smaller
What is the study of classification?
Taxonomy
Who invented classification?
Linnaeus
Heirarchy
domain
kingdom
phylum
class
order
family
genus
species
What are the domains?
archae, eukaryote, prokaryotes
What’s the oldest domain?
Archae
What are the kingdoms?
animals, plants, funghi, bacteria, protists
How do we name organisms?
Genus species (eg: Homo erectus, H. erectus)
What is convergent evolution?
When organisms evolve seperately to be similar
How can we tell if things are the same species?
Can their offspring reproduce?
What makes a plant a plant?
cellulose cell wall, photosynthesis
What makes funghi funghi?
chitin cell wall, no photosynthesis
What makes animals animals?
no cell wall, must eat
What makes bacteria bacteria?
no nucleus
artificial selection
selective breeding
can cause monoculture and health problems (eg: pugs’ breathing & bulldogs’ feet)
What is monoculture and why can it be a problem?
When everything is the same
No variation - a disease could wipe out everything
Genepool
all the alleles and genes within a breeding population
tissue culture
taking plant pieces (cuttings) and growing larger versions of them (eg: lavender, roses)
This is a form of cloning
Why can cloning plants be good?
- don’t need seeds or pollinators
- make whole plants from one cell
- useful for GM
- reduced chances of transmitting pests and diseases (produced in sterile containers)
- plants can grow which would struggle to reproduce naturally
What is genetic engineering?
altering an organism’s genome
Why can it be useful?
- protein can be produced synthetically
- insulin can be made synthetically (allows for Muslims and Jewish people to use it)
What is a vector?
a plasmid carrying DNA from one cell to another
How does genetic engineering work?
- Restriction enzymes cut the DNA at specific sites
- They leave complementary sticky ends where the bases are exposed
- Ligase enzyme helps to stick it back together
How is insulin made?
- The gene which codes for insulin is cut from human DNA using a restriction enzyme
- a plasmid is removed from a bacterial cell
- the plasmic is cut with a specific and complementary enzyme (the same one which cut the human DNA). This leaves complementary sticky ends.
- The sticky ends are joined with the enzyme ligase. A recombinant plasmid has just been made.
