Genetics and Variation Flashcards
Invertebrate
Animal without a backbone
Vertebrate
Animal with a backbone
Fish
Scales, live in water, coldblooded, eggs, gills
Amphibians
Smooth skin, live in water and on land, coldblooded, eggs
Reptiles
Scales, eggs, coldblooded, lungs
Mammals
Fur, warm-blooded, live births, lungs
Birds
Feathers, warm-blooded, eggs, lungs
Continuous Variation
Variation with no limit for population, plotted on line graph e.g. height
Discrete Variation
Variation with distinct groups, plotted on bar chart e.g. eye colour
Environmental Variation
Variations caused by the environment e.g. hair length, scars, handwriting, musical skills, accents
Inherited Variation
Variation caused by genes from parents e.g. nose shape, foot size, eye colour, freckles, blood group
Allele
Different forms of the same gene
Dominant
Characteristic that is expressed by genes that are the same or different
Gene
Section of DNA that codes for a particular characteristic
Genotype
The two alleles that an organism has
Heterozygous
Two different alleles e.g. Aa
Homozygous
Two of the same allele e.g. aa
Phenotype
Physical appearance due to genotype
Recessive
Characteristic that is expressed only when two genes are the same
Chromosome
Thread-like structures made of DNA
DNA
Material that genes are made of
Evolution
Process by which organisms have developed from earlier life forms on Earth
Extinction
The complete disappearance of a species from Earth
Fossil
The remains or impression of a prehistoric plant or animal embedded and preserved in petrified rock
Impression Fossils
Fossils of a dinosaurs footprint etc
Preserved Organisms
Organisms preserved in prehistoric tree resin (amber)
Mineral Replacement
Bones are buried and after they decay minerals create a copy of them in a sediment mould
Species
A group of organisms with characteristics in common and can produce fertile offspring
Variation
Differences between same species caused by genes
Mutation
Random change in genes
Causes of Extinction
Rapid environment changes, new predators, new diseases, new competition for food, natural disasters
