B15 - Genetics and Evolution theories Flashcards
1
Q
Mendel and homohybrid inheritance
A
- mendel carried out breeding experiements on plants
2
Q
mendel experiment observation
A
- inheritance of each characteristic is determined by units
- that are passed on unchanged to descendants
-characteristics are inherited in clear patterns
3
Q
After mendels death
A
- his work was finally accepted
- chromosomes were seen through a microscope
- behaviour of chromosomes during cell division was seen
4
Q
Early 20th century - after mendel
A
- observed that chromosomes and mendel’s units of inheritance behaved similarly
- units of inheritance (genes) were carried in chromosomes
5
Q
Mid 20th century discoverey
A
- structure of DNA
-mechanism of gene function
6
Q
development of gene theory
A
-genes code for proteins
-gives them their effect
7
Q
Darwin’s theory
A
- all species have evolved from the first simple life forms
- longer than 3 bn yrs ago
8
Q
Lamarch’s theory of evolution
A
- individual animals adapted to suit their environment
- everything evolved from primitive worms
- change caused by inheritence of acquired characteristics
9
Q
Lamarch’s belief about features developing
A
if used often it would develop
-useful changes = passed onto offspring
10
Q
objections for Lamarch’s theory
A
- no proof for fountain of life
- people didn’t like the idea of descending from worms
- changes (muscles) weren’t passed down
11
Q
fountain of life
A
all living organisms were linked
12
Q
Charles Darwins: survival of the fittest theory
A
- individuals in a species show variation for each characteristic
- reproduction = more offspring than environment can support
- organisms with characteristics that are best suited to the environment
- survive and breed = pass down characteristics
13
Q
Charles Darwin’s theory objections
A
- challenges beliefs about God
- lack of evidence
- no mechanism to explain variation
14
Q
Alfred Russel wallace proposed
A
- natural selection theory too
- best known for warning colouration in animals
15
Q
Speciation
A
where populations become so genetically different that they can no longer interbreed to produce fertile offspring
