inheritance Flashcards
The development of understanding of genetics and evolution
why was the theory of evoloution was contreversial and gradulaly accpeted, why?
- the theory challenged the idea that God made all the animals and plants that live on Earth
- there was insufficient evidence at the time the theory was published to convince many scientists
- the mechanism of inheritance and variation was not known until 50 years after the theory was published.
how did charles darwin come upwith theroy of evoloution?
as a result of observations on a round the world expedition, backed by years of experimentation and discussion and
linked to developing knowledge of geology and fossils, proposed the theory of evolution by natural selection.
what are the key principles of natural selection??
- Individual organisms within a particular species show a wide range of variation for a characteristic.
- Individuals with characteristics most suited to the environment are more likely to survive to breed successfully.
- The characteristics that have enabled these individuals to survive are then passed on to the next generation.
describe the development of our understanding of genetics including the work of Mendel?
In the mid-19th century Gregor Mendel carried out breeding experiments
on plants. One of his observations was that the inheritance of each characteristic is determined by ‘units’ that are passed on to descendants unchanged.In the late 19th century behaviour of chromosomes during cell division was observed
why the importance of Mendel’s discovery was not recognised until after his death?
In the early 20th century it was observed that chromosomes and Mendel’s ‘units’ behaved in similar ways. This led to the idea that the
‘units’, now called genes, were located on chromosomes.
In the mid-20th century the structure of DNA was determined and the
mechanism of gene function worked out.
what is the evidence for evoloution?
include fosslis + antibiotic reistant in bacteria
Evidence for Darwin’s theory is now available as it has been shown that characteristics are passed on to offspring in genes. There is further evidence in the fossil record and the knowledge of how resistance to antibiotics evolves in bacteria.
what are fossils?
‘remains’ of organisms from millions of years ago, which are found in rocks.
how can fossils be formed?
- from parts of organisms that have not decayed because one or more of the conditions needed for decay are absent
- when parts of the organism are replaced by minerals as they decay
- as preserved traces of organisms, such as footprints, burrows and rootlet traces.
what can we learn from fossils?
We can learn from fossils how much or how little different organisms have changed as life developed on Earth.
why are scientists not certain about how life began on Earth.
Many early forms of life were soft-bodied, which means that they have left few traces behind. What traces there were have been mainly destroyed by geological activity.
how can we reduce the rate of development of antibiotic resistant strains: (bacteria which is reisistive)
- doctors should not prescribe antibiotics inappropriately, such as treating non-serious or viral infections
- patients should complete their course of antibiotics so all bacteria are killed and none survive to mutate and form resistant strains
- the agricultural use of antibiotics should be restricted.
how does bacteria become resistive?
- Mutations of bacterial pathogens produce new strains. Some strains might be resistant to antibiotics, and so are not killed.
- They survive and reproduce, so the population of the resistant strain rises. The resistant strain will then spread because people are not immune to it and there is no effective treatment.
why is it hard to keep up with the resisitive strains?
The development of new antibiotics is costly and slow. It is unlikely to keep up with the emergence of new resistant strains
which bacteria is resistive to antibiotics?
MRSA
who made living things be classified into groups?
Carl
Linnaeus.
what are the categeroies the living things are are classified into?
- kingdom,
- phylum,
- class,
- order,
- family,
- genus
- species.
king philp came over for good soup
what is the binominal name?
the genus and the species of an animal
what are the three domain systems?
- archaea (primitive bacteria usually living in extreme environments)
- bacteria (true bacteria)
- eukaryota (which includes protists, fungi, plants and animals).
how did describe the impact of developments in biology affect the classification systems.
As evidence of internal structures became more developed due to improvements in microscopes, and **the understanding of biochemical **processes progressed, new models of classification were proposed.
what are evoloutionary trees used for and how?
Evolutionary trees are a method used by scientists to show how they
believe organisms are related. They use current classification data for living organisms and fossil data for extinct organisms.
