Variation and Evolution Flashcards
What is the variation within a species?
What can variation be caused by?
Differences within a species
Caused by the conditions in which an organism lives, or its genes.
What is kutation(
Changes to the genome, a random change in a DNA that can be inherited, e.g a mutation can change the eye colour slightly, but most things are controlled by more than one gene.
What is charles darwin’s description of evolution by natural selection?
Organisms in a species show a wide variation in their characteristics.
Organisms have to compete for resources in an ecosystem.
Means organisms with characteristics that make them better adapted to their environment will be better at competing with other organisms.
Makes them more likely to reproduce.
So genes with useful characteristics are more likely to be passed on to offspring, so useful characteristics are more common - evolution.
What is the theory of evolution?
all of todays species have evolved from simple life forms that first started to develop over three billion years ago.
What new evidence backs up Darwin’s theory of evolution?
Discovery of genetics - shows characteristics are passed on in genes, and genetic variants produce the characteristics that are better adapted to environment.
Fossils - showed how changes in organisms developed over time.
Antibiotic resistance - how bacteria are able to evolve to become resistant to antibiotics supports natural selection.
When do new species develop?
when populations of the same species change so much they can’t breed with eachother to produce fertile offspring.
How can animals become extinct?
Environment changes
New predator kills them all
New disease
Can’t compete with other species for food
Catastrophic event kills all (e.g volcano)
how can bacteria’s become antibiotic resistant
Bacteria develops random mutations in DNA, leading the bacteria to becoming resistant.
New strains of bacteria is called antibiotic resistant bacteria.
Means the bacteria will survive in a host who is being treated, and reproduce many more times.
What is selective breeding?
Where humans choose which plants or animals are going to breed, for usefulness or attractive ness.
E.g
Snkmd than produce more meat or milk.
Crops with disease resistance.
Dogs with good, gentle personality
Decorative plants with big or unusual flowers.
What is the basic process of selective breeding?
From existing plants or animal, select ones which have the feature you’re after and breed them together.
Select best offspring and breed them together - repeat.
What is disadvantages of selective breeding?
Reduces number of different alleles in a population.
Best animals or plants are always used for breeding, may make them related - inbreeding.
More chances of health problems because of this.
can be a serious problem if a new disease appears, as it makes it less likely individuals in he population still have alleles which make them resistant.
So if one individual is affected, rest are also likely to be.
What is genetic engineering used for and what is the process?
Used to give organisms new and useful characteristics.
Involves cutting a gene out of one organism and putting it into another organisms cells.
These are genetically modified organisms.
How is genetic engineering useful in agriculture?
Crops can be Genetically Modified to be resistant to herbicides, meaning that the farmers can spray crops to kill weeds without affecting the crop itself.
Can become resistant to insect or disease
Can be make to grow bigger and better fruit
This increase crop yield (amount of food produced)
How is genetic engineering useful in medicine?
Bacteria can be genetically engineered to produce human insulin.
Treatments using GM for inherited diseases are being researched.
What are some concerns of genetic engineering / modification in animals?
Can be hard to predict how changing an animal DNA will affect animal,
Many GM embryos don’t survive, or suffer from health problems.
What are some concerns of genetic modification / engineering in plants?
Could affect number of wild flowers and population of insects.
We might not understand effects of GM crops on human health.
What are fossils the remains of ?
organisms from many thousands of years ago found in rocks.
How are skeletons replaced by minerals ? (to create fossils)
Teeth, shells and bones don’t easily decay so last a long time when buried, When they do decay, they get replaced by minerals. The minerals form a rock like substance shape like the original hard part.
How are fossils formed from casts and impressions?
fossils can form when organisms are buried in soft material like clay, which hardens and organism decays.
Organisms leaves a cast of itself, or an animals button or a plant aroots,
How do fossils formed from being buried in places where no decay happens?
Decay microbes only work if there’s oxygen, moisture, warmth and the right OH,
E.G on mount everest, the lack of oxygen, warmth and moisture causes no decay.
What is classification)
Organisms organised by their characteristics.
E.g
Animals - fish, mammals reptiles, etc.
Plants - grasses, trees? etc.
Fungi - Mushrooms and toadstools? yeasts, e.g
Prokaryotes - all single celled organisms without a nucleus.
Protists - eukaryotic single celled organisms.
What are the kingdoms of classification?
Kingdom
Phylum
Class
Order
Family
Genus
Species
What is the new free domain classification system made by carl woese?
All organisms split into three domains which are then split into the kingdoms.
This is,
Eukaryota - included wide range of organisms - e.g fungi, plants, animals and protists
Archaea- Primitive bacteria, usually live in extreme places.
Bacteria - domain contains ‘true bacteria’
What is the binomial system?
Every organisms given two part latin name.
First part refers to the genus the organism belongs to, and second part refers to the species.
