Variation Flashcards
What is classification
Organising living organisms into groups
What are the five kingdoms
Animalia Plantae Fungi Protoctist Prokaryote
Describe the animal kingdom
They are heterotrophic so can’t make their own food and have to move about and find things to eat
They are multicellular so have more than one type of cell
They have no cell walls or chlorophyll
What is an allele
Different versions of the same gene
What is heterozygous
Two different alleles for a gene
What is homozygous
When the two alleles are the same for a gene
Can be recessive or dominant
What is phenotype
The characteristic you have e.g. Blue eyes
What is genotype
The genes or alleles that you have e.g. Hh
Describe the plant kingdom
They are multicellular so contain more than one type of cell
They’re autotrophic so can make their own food by photosynthesis
They have rigid cell walls and chlorophyll
Describe the fungi kingdom
They are saprophytes so feed off dead organisms and decaying material
They’re multicellular so contain more than one type of cell
They have a cell wall but no chlorophyll
Describe the protoctist kingdom
They are uni cellular so have one type of cell
They have a nucleus
Describe the prokaryote kingdom
They’re unicellular
They have no nucleus
What is used to classify organisms
Kingdom Phylum Class Order Family Genus Species
What is the phylum Chordata
It’s made up of animals that all have a supporting rod structure up the back of their body e.g. A back bone
What are the different ways vertebrates absorb oxygen
Lungs eg birds
Gills eg fish
Skin eg amphibians
What are the different watch vertebrates can reproduce
Internal fertilisation eg mammals
External fertilisation eg fish
Oviparous eg reptiles they lay eggs
Viviparous eg mammals they give birth to live young
What are the different ways vertebrates can regulate their body temp
Homeothermic means they’re warm blooded and can regulate their own body temp eg mammals
Poikilothermic means their temperature changes with the external environment eg reptiles
Why isn’t accurate classification always easy
Newly discovered species don’t always fit into any of the categories or fit into more than one
Some species reproduce asexually not interbreed like the definition
You can get hybrids that can be fertile
There’s lots of variation between species eg breeds of dog
You can get ring speices
What is a species
Organisms in the same species can interbreed to produce fertile offspring
What is a ring species
A group of related populations that live in neighbouring areas the populations that live next to each other can produce fertile offspring but populations that live further apart can’t so it’s hard to tell if the populations are in the same species
What is the binomial system
Each species has a two part Latin name
The first part is the genus
The second part is the species
Eg Homo sapiens
How is the binomial system useful
Helps identify species where common names mean different things
Helps us study species because people can share information on them
It helps us conserve species because two similar looking species could appear to be in the same species so only one of the speices is protected
Helps us target conservation efforts because we can protect areas with lots of variety of species
What is a key
It’s a series of questions used to find out what an unknown organism is
What is variation within species
When organisms in the same species look different
It’s caused by genes and the environment
What is genetic variation
An organisms characteristics are inherited from its parents
Some genes are from the mother and some from the father
The two sets of genes combining causes variation
Also mutations in genes can cause genetic variation
Some variations are caused only by genes e.g. Eye colour and inherited disorders
What is environmental variation
The place where organisms live and grow causes differences between members of the same species
Eg. Plant in the dark will be yellow but the same pant in the light will be much bigger and green
The factors that can cause environmental variation are diet, exercise, temperature, light levels, amount of water etc
What characteristics are caused by the genes and the environment
Body weight skin colour etc
Eg the maximum height you can grow to is genetic but the height you actually grow to is environmental
What is continuous variation
When the individuals in a population vary within a range
There are no distinct categories
Eg mass
It causes a natural distribution or bell curve
What is discontinuous variation
When there are two or more different categories and the individual only falls into one of them there are no intermediates
Eg blood group
How can you show continuous variation
Record a group of peoples hand span and you will be able to draw a graph showing the natural distribution curve
How can you show discontinuous variation
Record the eye colour of a group of people and each person will fit into a distinct category
How are organisms adapted to living in the deep sea
There is little food
Some can emit light from parts of their bodies eg the angler fish has a light rod sticking out of its head that attracts prey which the angler fish eats
They usually have huge mouths so they can move along the sea bed scraping up food
They can have huge eyes adapted to the dark or feelers on their body so they can feel where they’re going
How are creatures adapted to living in volcanic vents in the sea bed
The chemicals support the bacteria so they can make their own food using chemical energy (chemosynthesis) which is like photosynthesis but uses chemical energy instead of light energy
The bacteria are at the bottom of the food chain and animals feed on them
They are adapted to cope with the high heat and pressure
How is the deep sea Pompeii worm adapted
It has a thick layer of bacteria to protect it from the heat
It can go inside a papery tube to protect it from predators
How are polar bears adapted
They have a compact shape giving them a small surface area to reduce heat loss
They have a thick layer off blubber for insulation and an energy store if there’s little food
Thick hairy coats trap a layer of warm air near the skin
Greasy fur shears water preventing cooling by evaporation
Big feet spread their weight so they don’t sink into the snow
White fur for camouflage
How are penguins adapted
They have a thick layer of fat for insulation and energy store
They have oily feathers to shed water
Huddle together in groups to conserve heat
Streamlined body to reduce water resistance so they can swim faster to catch more fish
What is natural selection
There’s variation within species
Most organisms have more young than can survive to adulthood
There completion for resources
The individuals with adaptations that mean it’s easier to get the resources are more likely to survive and breed successfully
So the responsible gene is more likely to get passed on to the next generation
The ones that are less well adapted are less likely to survive so will eventually die out
Over time the better adapted characteristic becomes more common and the bad adaptation dies out
What is evolution
The slow and continuous change of organisms from one generation to the next
How does DNA research support evolution
The theory suggests that all organisms come from one common ancestor
Closely related species separated more recently
Evolution is caused by gradual changes in DNA
So organisms that separated more recently should have more similar DNA e.g. Humans and chimps have similar DNA
How do resistant organisms support evolution
The poison warfarin is used to kill rats
But a certain gene gives resistance to warfarin so these rats are more likely to survive and breed
So now there are are rat populations that are warfarin resistant
How does the scientific community validate evidence
Scientific journals are where scientists can publish their findings so other scientists can repeat the experiments
Peer review is when scientists get other scientists to review their work
Scientific conferences where scientists attest to discuss their findings
What is speciation
When populations of the same species become so different they can no longer produce fertile offspring
What is stage one of speciation
Isolation
When the populations are separated usually by a physical barrier
Eg earthquake or flood can cause barriers that geographically isolate some individuals from the population
What is stage two of speciation
Conditions on either side of the barrier will be slightly different e.g. They may have different climates so natural selection occurs
What is stage three of speciation
Eventually the individuals from each population will have become so different that they can no longer breed to produce fertile offspring and there will be two separate species
What are chromosomes
They’re found in the nucleus and they carry genes
What are they symptoms of cystic fibrosis
Recessive Genetic disorder so both parents must be carriers or sufferers
There’s lots of mucus produced by the body in the air passages gut and pancreas
Breathing difficulties
Lung infections
Malnutrition and fertility problems
Wha is genetic screening
When a cells genes are analysed to find out if it carries a specific alleles
What is sickle cell anaemia
Causes funny shaped red blood cells
Which can get stuck in the capillaries depriving the body cells of oxygen
Symptoms are dizziness, tiredness, painful joints and muscles, fever anaemia
It is a recessive genetic disorder
