B5 Flashcards
(40 cards)
1
Q
what is the defining characteristic of a species?
A
- a group of organisms that have similar characteristics that can interbreed to produce fertile offspring
2
Q
What are some genotype only characteristics?
A
- gender
- dimples
- ability to roll tongue
3
Q
What are some phenotype only characteristics?
A
- accent
- tan
4
Q
what are some characteristics of both genotype and phenotype?
A
- height
-weight
5
Q
What is a mutation?
A
mutations are changes in the DNA base sequence of an organism
6
Q
How is mutation caused?
A
- by uv radiation
- by ionising radiation
- some chemicals
- mistake made during mitosis
7
Q
what can some effects of mutation be?
A
- no alteration to phenotype
- some can cause uncontrollable cell division - cancer
- some may alter the phenotype but do not affect survival - (e.g tongue rolling)
- may affect the shape of proteins
- some can be benefical
8
Q
what is the difference between discontinuous and continuous variation?
A
- discontinuous variation has a set number of values it can fall into, e.g blood type
- continuous variation has value that can be within a max and a min, e.g height
9
Q
what are the 2 gametes in animals?
A
egg + sperm
10
Q
what are the 2 gametes in plants?
A
pollen grain + egg
11
Q
What are advantages of sexual reproduction?
A
- getting variation in the species so new characteristics may be selected which is good if species is struggling
12
Q
what are the disadvantages of sexual reproduction?
A
- reproduction is slow
- few offspring are produced
- if species has dominant characteristic then this may be lost in natural variation
13
Q
benefits of asexual reporoduction?
A
- large number of offspring produced
- reproduction is much faster
- clones the parent which is good for a dominant characteristc
14
Q
costs of asexual reproduction?
A
- if there is an environmental change then all the plants will be affected as they are all clones and there is no variation
15
Q
Name 3 differences between mitosis and meiosis?
A
- mitosis is much faster than meiosis
- mitosis produces 2 identical daughter cells while meiosis produces 4 genetically different daughter cells
- the mitosis daughter cells each have 46 chromosomes, while each meiosis cells each have 23 chromosomes
16
Q
Where does mitosis and meiosis occur?
A
- mitosis occurs in humans everywhere except the sex organs and exclusively takes place in the bacteria (binary fission)
- meiosis occurs in the human sex organs
17
Q
what is meiosis and mitosis used for ?
A
- meiosis is used for production of gametes
- mitosis is used by the body for growth and repair
18
Q
Is there any variation in mitosis and meiosis?
A
- there is variation in meiosis but not mitosis
19
Q
Describe the process of meiosis?
A
- the genetical material in a cell all duplicates and lines up in the centre of the cell, each corresponding chromosome lined up with each other but maternal and paternal can be randomly on either side
- the cell splits into two, each carrying 2 sets of each type of chromosome
- the cell then further splits into two leaving 4 cells with 1 set of each chromosome
20
Q
what is the phenotype?
A
- the part of the gene that physically appears on the organism
21
Q
What is the definition of a gene?
A
- a piece of genetic material that controls the expression of the characteristic
22
Q
What is an allele?
A
- a variation of the gene that displays as version of the characteristic
23
Q
What is the Mendel Tall/Short Experiment?
A
- crossed tall pea plants with short pea plants, the pea plants were always tall
- showed that tall was a dominant characteristic
24
Q
What is the definition of a genotype?
A
- the alleles that a person has for a specific gene/trait
25
For a punnet square what do you write out first?
1. Phenotype
2. Genotype
3. Gametes (in circles)
26
What symbols do we use for human reproduction in punnet squares?
XY - boys, XX - girls
27
What type of allele is Cystic Fibrosis caused by?
recessive
28
What type of allele is Huntingdon’s caused by?
dominant
29
What is the general way natural selection is come about?
1. Variations exist in the population due to mutations (random changes in the DNA) which affect characteristics
2. Advantageous characteristics mean that some individuals will survive/ are more likely to survive longer with time to reproduce
3. Offspring may inherit this and therefore will be more likely to survive and reproduce, while non-mutated parts of the species are more likely to die and not reproduce
4. This chain continues as the frequency of the advantageous characteristic increases over time
30
What is evolution?
change in the inherited characteristic of a population
31
Why do bacteria evolve more quickly than other species?
- because they reproduce rapidly
32
What did Darwin do on the galapagos islands?
- looked at different types of the same bird, some of which had speciated due to barrier between them and could no longer have fertile offrsping
33
What did Wallace do?
- Wallace found the same theory as Darwin, but went to Indonesian island
- Darwin published his idea first however
- he studies caterpillars
34
What are some ways to prove evolution?
1. Fossil Formation/ Ice Freezing
2. Antibiotic Resistance by bacteria
35
What is extinction?
- loss of all individuals in the same species
36
Should ant-biotics be used for viral infections?
No they are ineffective, only work against bacteria
37
What is the divisions in the binomial classification system?
1. Kingdom
2. Phylum
3. Class
4. Order
5. Family
6. Genus
7. Species
38
What is the binomial name?
Genus + Species
written underlined
39
What is the definition of classification?
- the process of sorting living organisms into groups
40
What is phylogenetics?
study of relationships between organisms and their evolutionary history
