B1.1 Classification, variation and inheritance Flashcards
What are characteristics?
The features of an organism
What is classification?
The grouping of organisms based on their characteristics
What is the order of the different classification levels?
- kingdom
- phylum
- class
- order
- family
- genus
- species
What are the five different types of kingdoms of organisms?
- animalia
- plantae
- fungi
- protoctista
- prokaryotae
What does unicellular mean?
Single-celled
What does it mean when an organism is multicellular?
It is made of many cells
Do bacteria contain a nucleus?
No
What process do plants use to make their food?
Photosynthesis
What does it mean when an organism is autotrophic?
It can make its own food from substances that weren’t alive
What does it mean when an organism is heterotrophic?
It gets food by eating and digesting other organisms
What does it mean when an organism is saprophytic?
It gets food by digesting dead or decaying organisms outside the body
What kingdom are organisms that don’t contain a nucleus from?
Prokaryotae
What are the main characteristics of organisms in the kingdom animalia?
- multicellular
- heterotrophic feeders
- no cell walls
- complex cell structure
- contains nucleus
What are the main characteristics of organisms in the kingdom plantae?
- multicellular
- autotrophic
- have cell walls
- complex cell structure
- nucleus
What are the main characteristics of organisms in the kingdom fungi?
- multicellular
- cell walls
- saprophytic
- complex cell structure
- nucleus
What are the main characteristics of organisms in the kingdom protoctista?
- mostly unicellular (some multicellular)
- complex cell structure
- nucleus
What are the main characteristics of organisms in the kingdom prokaryotae?
- unicellular
- simple cell structure
- no nucleus
What are the cell walls of fungi made from?
Chitin
What are the cell walls of plants made from?
Cellulose
Why aren’t viruses considered to be alive?
They don’t carry out all of the seven life processes
What are vertebrates?
Animals with a backbone
What phylum do all vertebrates belong to?
Chordata
What are invertebrates?
Animals that don’t have a backbone
What are the different ways animals can absorb oxygen?
- by their gills
- through the skin
- with their lungs
What are the five different groups of vertebrates?
- fish
- amphibians
- mammals
- reptiles
- birds
What is external fertilisation?
Fertilisation that happens outside the body
What is internal fertilisation?
Fertilisation that happens inside the body
What do oviparous animals do?
Lay eggs
What do viviparous animals do?
Give birth to live young
What does it mean when an animal is a homeotherm?
It keeps its body temperature constant, and it’s often warmer than its surroundings
What does it mean when an animal is a poikilotherm?
It’s temperature varies with its surroundings
What is a specie?
A group of organisms that can interbreed to produce fertile offspring
What does fertile mean?
Able to reproduce
What are hybrids?
The offspring of two closely related different species
Are hybrids usually fertile or infertile?
Infertile
What does infertile mean?
Unable to reproduce
What are ring species?
A chain of different populations that can interbreed with near populations except for the two at the end of the chain
What is variation?
Differences in characteristics
What does accurate classification allow biologists to do?
- easily identify existing species and new species
- see how organisms are related
- identify areas of greater and lesser biodiversity
What is biodiversity?
The measure of the total number of different species in an area
What are the benefits of an area being more biodiverse?
- more living things to produce food and medicines from
- they are better at recovering from natural disasters
What are biodiversity hotspots?
Areas of high biodiversity
What is continuous variation?
Value that can be any number within a certain range
What is discontinuous variation?
Variation that only has a fixed set of values
What type of variation can affect human height?
Inherited and environmental variation
What are adaptions?
Characteristics that allow an organism to survive in a habitat
What is a habitat?
The place where an organism lives
What adaptions do polar bears have for their habitat?
- small ears to stop losing too much heat
- white fur for camouflage
- thick layer of blubber for insulation
- rough soles of feet to grip ice
- large feet to spread out weight, stop sinking and be good at swimming
- thick fur for insulation
What adaptions do deep sea worms have for hydrothermal vents?
- has a papery tube to protect from predators
- no eyes but sensitive tentacles because they live in complete darkness
- covered in a thick layer of bacteria that protects against the high heat
What does the normal distribution curve show?
The greatest amount of individuals with the same variation values in the middle and those with more extreme values at the beginning and end of the curve
What is an acquired characteristic?
A characteristic caused by the environment instead of genes
Why do many offspring die before they reach adulthood?
There aren’t enough resources for them all
What causes competition between organisms?
Limited resources
What is natural selection?
The process where organisms with variations better adapted to the environment are more likely to survive and those that don’t die
Who came up with the theory of evolution?
Charles Darwin
What does it mean when a species is extinct?
All of them have died out
What is evolution?
The gradual change of a species over time because of natural selection
What does it mean when a specie is resistant to something?
It isn’t affected by it
What is speciation?
The process by which a species spreads to different places and the environmental factors cause adaptions that turn them all into separate species that can no longer interbreed
What is a chromosome?
A strand of DNA
Where is DNA found?
In the nucleus
Where are genes found?
In chromosomes
What is inherited variation?
Variation caused by genes inherited from parents
What are alleles?
Different forms of the same gene
What do genes do?
Give instructions for a particular cell activity or the production of a protein
How many copies of a chromosome are there in a body cell nucleus?
Two
How many chromosomes does a human body cell contain?
46
What are gametes?
Sex cells
What are the male gametes in animals?
Sperm cells
What are the male gametes in plants?
Pollen grains
What are the female gametes in plants and animals?
Egg cells
Why are gametes different to most body cells?
They only have one copy of each chromosome instead of two
What does it mean when an allele is dominant?
It will always have an effect
What does it mean if an allele is recessive?
It will only have effect if there is no dominant allele present
What is the genotype?
The alleles in an organism
What is the phenotype?
What an organism looks like
What does it mean when a gene is homozygous?
Both its alleles are the same
What does it mean when a gene is heterozygous?
It’s alleles are different
In what two ways can a genotype be shown?
- a genetic cross diagram
- a Punnett square
What causes a genetic disorder?
Faulty alleles
Why can people with sickle cell disease have painful joints?
Their red blood cells stick together and block blood vessels
Why can sickle cell disease be fatal?
It can cause blocked blood vessels
What are the symptoms of sickle cell disease?
- tiredness
- shortness of breath
- painful joints
Why do people with sickle cell disease have trouble breathing?
Their red blood cell cells are sickle-shaped instead of globular so they can’t pick up oxygen as well
Why can cystic fibrosis cause weight loss?
Mucus can block some of the tubes that carry enzymes to the small intestine to digest food
Why do people with cystic fibrosis have trouble breathing?
Their lungs get clogged with a thick mucus
What does the thick mucus in people with cystic fibrosis increase the risk of?
Infections
