B5 Flashcards
what is the defining characteristic of a species?
- a group of organisms that have similar characteristics that can interbreed to produce fertile offspring
What are some genotype only characteristics?
- gender
- dimples
- ability to roll tongue
What are some phenotype only characteristics?
- accent
- tan
what are some characteristics of both genotype and phenotype?
- height
-weight
What is a mutation?
mutations are changes in the DNA base sequence of an organism
How is mutation caused?
- by uv radiation
- by ionising radiation
- some chemicals
- mistake made during mitosis
what can some effects of mutation be?
- 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
what is the difference between discontinuous and continuous variation?
- 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
what are the 2 gametes in animals?
egg + sperm
what are the 2 gametes in plants?
pollen grain + egg
What are advantages of sexual reproduction?
- getting variation in the species so new characteristics may be selected which is good if species is struggling
what are the disadvantages of sexual reproduction?
- reproduction is slow
- few offspring are produced
- if species has dominant characteristic then this may be lost in natural variation
benefits of asexual reporoduction?
- large number of offspring produced
- reproduction is much faster
- clones the parent which is good for a dominant characteristc
costs of asexual reproduction?
- if there is an environmental change then all the plants will be affected as they are all clones and there is no variation
Name 3 differences between mitosis and meiosis?
- 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
Where does mitosis and meiosis occur?
- 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
what is meiosis and mitosis used for ?
- meiosis is used for production of gametes
- mitosis is used by the body for growth and repair
Is there any variation in mitosis and meiosis?
- there is variation in meiosis but not mitosis
Describe the process of meiosis?
- 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
what is the phenotype?
- the part of the gene that physically appears on the organism
What is the definition of a gene?
- a piece of genetic material that controls the expression of the characteristic
What is an allele?
- a variation of the gene that displays as version of the characteristic
What is the Mendel Tall/Short Experiment?
- crossed tall pea plants with short pea plants, the pea plants were always tall
- showed that tall was a dominant characteristic
What is the definition of a genotype?
- the alleles that a person has for a specific gene/trait
For a punnet square what do you write out first?
- Phenotype
- Genotype
- Gametes (in circles)
What symbols do we use for human reproduction in punnet squares?
XY - boys, XX - girls
What type of allele is Cystic Fibrosis caused by?
recessive
What type of allele is Huntingdon’s caused by?
dominant
What is the general way natural selection is come about?
- Variations exist in the population due to mutations (random changes in the DNA) which affect characteristics
- Advantageous characteristics mean that some individuals will survive/ are more likely to survive longer with time to reproduce
- 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
- This chain continues as the frequency of the advantageous characteristic increases over time
What is evolution?
change in the inherited characteristic of a population
Why do bacteria evolve more quickly than other species?
- because they reproduce rapidly
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
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
What are some ways to prove evolution?
- Fossil Formation/ Ice Freezing
- Antibiotic Resistance by bacteria
What is extinction?
- loss of all individuals in the same species
Should ant-biotics be used for viral infections?
No they are ineffective, only work against bacteria
What is the divisions in the binomial classification system?
- Kingdom
- Phylum
- Class
- Order
- Family
- Genus
- Species
What is the binomial name?
Genus + Species
written underlined
What is the definition of classification?
- the process of sorting living organisms into groups
What is phylogenetics?
study of relationships between organisms and their evolutionary history
