Classification & Variation Flashcards
What phylum do vertebrates come under?
Chordata
What is the classification system?
Kingdom Phylum Class Order Family Genus Species
What Kingdom is bacteria in?
Prokaryote
Why are protoctists different from prokaryotes?
They have a nucleus
Give an example of a protoctist
Algae
Are animals heterotrophs or autotrophs?
Heterotrophs
What is a ‘poikilotherm’?
An organism who’s body temperate depends on the outside environment
How do you know when organisms are of the same species?
They can interbreed to produce fertile offspring
In a binomial system, what is the first part of the two part name?
Genus
What type of variation is when a plant gets yellow leaves?
Environmental
What type of variation is skin colour?
Both
With continuous variation, most organisms will have a height around…
The mean
How do you know when variation is discontinuous?
There are distinct categories
How have angler fish adapted to deep sea life?
Rod shaped spine which emits light to attract prey
How has the rat tail fish adapted to deep sea life?
A big mouth which scoops up particles of food along the seabed
What is chemosynthesis?
When organisms can make their own food using chemical energy
What process enables bacteria to survive off the chemicals in hydrothermal vents?
Chemosynthesis
What does a low surface area compared to volume of a polar bear do to help it survive in a polar region?
Reduces heat loss
Why do polar bears have a thick layer of blubber?
For insulation and an energy store when food is scarce
Why do polar bears have wide feet?
To spread their weight so they don’t break thin ice or sink into snow
Why do penguins huddle together?
To conserve heat
Why do penguins have a streamlined body?
To reduce water resistance so they can swim fast and catch fish
Who came up with the theory of natural selection?
Charles Darwin
Describe the process of natural selection
1) there is variation between organisms of the same species due to mutations in genes and inherited variation
2) most organisms produce more offspring than will survive
3) populations have to compete for food, water and mates to survive
4) individuals with characteristics suited to their environment means a better chance of survival
5) this means they can survive breed and pass on their advantageous genes
6) those less suited are less able to compete for survival and so are less likely to survive and pass on their genes through reproduction
7) over time there will be a higher number of individuals with the beneficial characteristics so eventually the poorly adapted characteristics are lost and the species has evolved.
What process drives evolution?
Natural selection
What two main things support evolution?
DNA research
Resistant organisms
What happened with warfarin to support the theory of evolution?
1) warfarin poison used to kill rats
2) a certain gene made rats resistant to warfarin so those rats survived, reproduced and passed on their advantageous gene
3) there are now warfarin resistant populations of rats
How did the scientific community validate evidence about evolution?
Publishing their work in scientific journals
Peer reviewing their findings
Holding scientific conferences/meetings to present an discuss their work
What is ‘speciation’?
The development of a new species
When does speciation occur?
When populations of the same species become so different that they can no longer interbreed to produce fertile offspring
Explain the process of speciation.
1) geographical isolation between populations
2) different environmental conditions on either side of the barrier between populations
3) populations adapt to new environments- different characteristics will be advantageous on either side of the barrier so natural selection will occur
4) eventually individuals from different populations will have changed so much that they won’t be able to breed with each other to produce fertile offspring. The two groups have become separate species
What are chromosomes?
Long lengths of DNA coiled up
What is a gene?
A short section of DNA
What is an allele?
A different version of the same gene
Where is DNA found?
In the nucleus of a cell
What does a genetic diagram show?
The possible genes of offspring
What does ‘homozygous’ mean?
An organism has two alleles for a particular gene that are the same
What does ‘heterozygous’ mean?
An organism has two alleles for a particular gene that are different
What is the allele for a characteristic that is shown?
The dominant allele
How can an organism display a recessive characteristic and why?
Both it’s alleles must be recessive because the dominant allele overrules the recessive one
What is a genotype?
The alleles you have
What is a phenotype?
The characteristic you have
Which type of allele causes cystic fibrosis?
Recessive
With cystic fibrosis, what is a carrier?
Someone who has only one copy of the allele for the disorder so doesn’t suffer from it
What are the results of having cystic fibrosis?
Body produces a sticky mucus in the air passages, gut and pancreas
What are the symptoms of cystic fibrosis?
Breathing difficulties
Lung infections
malnutrition
Fertility problems
How can a child inherit cystic fibrosis?
Both parents must be carriers or sufferers
If both parents carry the allele for cystic fibrosis but do not suffer from the disorder, what is the chance of a child inheriting the disorder?
1 in 4
How can genetic disorders be detected?
By analysing a cell’s genes - known as screening
What does sickle cell anaemia do to red blood cells?
Red blood cells become sickle shaped so have a smaller surface area which means they carry less oxygen
What are the symptoms of sickle cell anaemia?
Tiredness
Painful joints and muscles
Fever
Anaemia
