B15: Genetics & Evolution Flashcards
What are 3 facts about natural selection?
Individuals within a species show a wide range of variation, individuals with characteristics most suited to the environment are most likely to survive and breed successfully and characteristics that have enabled these individuals to survive are passed on to the next generation
Why was the theory of evolution by natural selection only gradually accepted?
The theory challenged the idea that God made all animals, there was insufficient evidence at the time and the mechanism of inheritance and variation was not known until 50 years after
What are fossils?
Remains of organisms from millions of years ago which are found in rocks
What are 3 ways fossils can be formed?
From parts of organisms that have not decayed because one or more conditions needed for decay are absent, when parts of organisms are replaced by minerals as they decay and as preserved traces of organisms, such as footprints
What does soft-bodied mean?
They have left a few traces behin
Why can’t scientists be certain of how life began on earth?
Because traces were destroyed mainly by geological activity
What is extinction?
The process of remaining individuals in a species die
How can the rate of development antibiotic resistant strains be reduced?
Doctors should not prescribe antibiotics inappropriately, patients should complete a full course of antibiotics so bacteria are killed and the agricultural use of antibiotics should be restricted
What are disadvantages to the development of antibiotics?
They are costly and slow
How are living things classified?
Depending on their structure and characteristics in a system
What is the order of classification?
Kingdom, phylum, class, order, family, genus, species
How are organisms named?
Binomial system of genus and species
What are organisms divided into in the ‘three-domain system’?
Archea (primitive bacteria in extreme conditions), bacteria and eukaryota (protists, fungi, animals and plants)
How were closely related species separated?
Geographical barriers such as a wide river
What are similarities between Alfred Wallace and Darwin?
Both spent time on Islands and published books on findings and
Why is antibiotic resistance evidence for natural selection?
Bacteria reproduce rapidly and mutations occur during reproduction. If a mutated bacterium is resistant, it will survive exposure to the antibiotic and reproduce. The bacterium will represent the original ancestor of a new resistant strain
What causes slower extinctions? What causes faster ones?
Geological and atmospheric changes happening overtime. Abiotic factors
What can volcanic eruptions change levels of?
Soil pH, carbon dioxide and light
Who performed breeding experiments on pea plants in 19th century?`
Gregor Mendel
What was used to categorise species in the Linnaean system?
Appearance
What 3 traits did Mendel study?
Height, colour of flower and colour of pea
Describe how antibiotic resistance arises?
Person takes antibiotics, some bacteria get random mutations making them less susceptible to the antibiotic. Antibiotic kills unresistant bacteria and the resistant strains now have more room to colonise
What is Alfred Wallace best known for?
Studying warning colouration in animals, (e.g. Golden Birdwing Butterfly) and speciation
Why may speciation occur?
Due to isolation and natural selection
