| A | B |
|---|
| biodiversity | the wide range of organisms that exist |
| variation is due to | inherited and environmental factors |
| inherited factors | can also be described as genetic factors |
| species | organisms which can breed to produce fertile offspring |
| fertile | able to reproduce |
| infertile | unable to reproduce |
| genes are | the units of inheritance |
| chromosomes are found | in a nucleus |
| nuclei | more than one nucleus |
| chromosomes are made up | of genes |
| genes are made of | DNA |
| DNA stands for | deoxyribonucleic acid |
| genetic information | is passed from one generation to the next |
| scientist who started work on genetics | Gregor Mendel |
| scientists who determined the structure of DNA | Watson, Crick ( and Franklin!) |
| number of chromosomes in a human body cell | 46 |
| number of chromosomes in a human gamete (sex cell) | 23 |
| gametes | sperm cells and egg cells |
| the shape of DNA | double helix |
| scientist whose theory was natural selection | Charles Darwin |
| natural selection | survival of the fittest |
| rcompetition between organisms | leads to the development of adaptations |
| evolution takes place | very slowly |
| selective breeding | = artificial selection |
| extinction | when a species no longer exists |
| endangered | when a species is close to becoming extinct |
| gene banks are | stores of tissue or cell samples from endangered species |
| changes which can lead to extinction | climate change, predators, disease. |
