SB4 Flashcards
What is the binomial system
The system of naming organisms using Latin words
What is evolution
The gradual change in characteristics of a species over time
Why can’t we be sure that human-like animals evolved into modern humans
Because there are gaps in fossil evidence
What is natural selection
A process in which certain organisms are more likely to survive because they possess certain genetic variations
Why should people finish using their antibiotics fully and not stop early
As the antibiotics kill more and more bacteria, more bacteria grow resistant to it and the most resistant bacteria will take the longest to die. This bacteria can replicate and create more resistant bacteria so now the new population of bacteria are fully resistant
What causes faster evolution
An external factor, forcing a species to evolve, eg: rats being killed with warfarin led to the entire species being resistant
What is a pentadactyl limb
A limb that has five digits (thumbs and fingers) shared by all vertebrate
What does the pentadactyl limb suggest
Despite different animals having different limb structures, this would suggest a common ancestor between them
How many kingdoms of classification are there
5
Why can we not use characteristics for classification
A lot of species look similar but do not have common ancestors, eg: fossa and other types of cats
What 3 domains are all organisms divided into
Archaea, eukarya and bacteria
What are properties of archaea
Cells with no nucleus, genes contain unused sections of DNA
What are properties of bacteria
Cells with no nucleus, no unused sections in genes
What are properties of eukarya
Cells with a nucleus, unused sections in DNA
What are the main characteristics of animals
Multicellular with cells arranged as tissues and organs, cells with nuclei and no cell walls
What are the main characteristics of plants
Multicellular with plants arranged as tissues and organs, have chloroplasts for photosynthesis, cell walls and nuclei
What are the main characteristics of fungi
Multicellular (except yeasts), live and feed on dead matter, cells have nuclei, cell walls that contain chitin
What are the main characteristics of protists
Mostly unicellular (some are multicellular) cells have nuclei, some have cell walls
What are the main characteristics of prokaryotes
Unicellular, cells do not have nuclei, flexible cell walls
What is artificial selection
When humans choose certain organisms because they have useful characteristics
What is selective breeding
Humans repeatedly breeding a species with desired characteristics for a prolonged period of time
State reasons why plants and animals are often selectively bred
- Flavour
- Disease resistance
- Yield
- Coping with certain environmental conditions
- Fast growth
What are GMOs
Genetically modified organisms, made by genetic engineering
What is genetic engineering
Changing the DNA of one organism by inserting genes from another
What is one advantage and disadvantage of genetic engineering
Quicker than artificial selection but it’s more expensive
What is tissue culture
The growing of cells or tissues in a liquid containing nutrients or on a solid medium
What is a callus
A clump of undifferentiated cells
What is tissue culture used for
Growing identical cells
What is tissue culture used for
Growing identical cells
What is the method for tissue culture (cloning plants)
1) Piece of plant is placed in bleach solution to sterilise it
2) Plant hormones added to piece of plant so it grows shoots and roots
3) When plant is large enough, it’s placed into soil or compost to grow
What are risks of selective breeding
All organisms are very similar so if one organism is affected by a change in condition, all organisms will be effected
Alleles needed in the future may not exist
Animal welfare, some animals might be so fat that they cannot stand
What are some genetic engineering issues
- The seeds for GM plants are expensive
- Some think that eating GMOs are bad for health
- Some think that GM crops will reproduce with wild plants, passing their resistant genes
How is bacteria genetically engineered
1) Restriction enzymes are used to cut a useful gene out of the organism (leaves it with sticky ends)
2) Restriction enzymes are also used to cut plasmids open
3) Two matching sticky ends can be joined using ligase (enzyme)
4) Plasmids are inserted back into bacteria
What is yield
The amount of crop we can use
What is the Bt toxin
A natural insecticide
What is an advantage of Bt toxin
It only affects insects that chew the plant tissues
What is a problem with growing plants
- If they make their own insecticide, the insects can become resistant to it
- Pests can eat it
What is a problem with growing plants
If they make their own insecticide, the insects can become resistant to it
How can we solve insect’s resistance to insecticide
Produce new GM versions of the plant to replace the varieties that pests are resistant to
What is biological control
Using organisms to control pests
What are some disadvantages of fertiliser
- If not all fertiliser is absorbed by crops, it can get into streams, rivers and lakes, causing pollution and death of organisms
- Can cause health problems in humans and animals if they drink the water
What are advantages of fertiliser
-Increases the growth and yield of crop plants
