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| Question | Answer |
| Describe characteristics of organisms in the animal kingdom. | Multicellular; heterotrophic; no cell walls; complex cell structure with nucleus. |
| What main characteristic do organisms in the Chordata phylum have in common? | They all have a supporting rod-like structure that goes up the back of the body. |
| What do all vertebrates have in common? | A backbone. |
| What does oviparous mean and name a group of vertebrates that are oviparous. | An animal which lays eggs. Birds. |
| What is a species? | A group of living organisms consisting of similar individuals capable of interbreeding. |
| What is the name of the offspring of two different species? | A hybrid. |
| In the binomial system each organism is given a two-part name. What does each part refer to? | The genus and the species. |
| Other than the environment, what causes variation? | Genes. |
| List three features of animals which aren't affected at all by environment, and three which are. | Eye colour, blood group and inherited disorders. Weight, fur colour and body mass. |
| What is continuous variation? | When the individuals in a population vary within a range. |
| What is discontinuous variation? | When there are two or more distinct categories where individuals only fall into one of them. |
| Give an example of a feature in humans where there is continuous variation. | Height. |
| Give an example of a feature in humans where there is discontinuous variation. | Eye colour. |
| Explain two ways that deep-sea fish have adapted to their habitat. | Some deep-sea fish are able to emit light from parts of their body. Some have large eyes adapted to the dark. |
| Explain two ways that polar bears are adapted to living in polar regions. | They have a thick layer of blubber for insulation. They have thick hairy coats which trap a layer of warm air next to the skin. |
| Explain Darwin's theory of natural selection. | There is variation in the genes of a population of organisms. Some have more favorable characteristics due to these genes which make them better survivors and more likely to breed. They are better adapted to their environment. These characteristics get passed on to the next generation. The organisms that are less well adapted may be less able to survive and then reproduce. This means the number of better adapted organisms will increase while the less well adapted will eventually die out. |
| Give three ways that the scientific community validate evidence. | Through peer reviews, scientific journals and scientific conferences. |
| What is speciation? Explain how geographical isolation can lead to speciation. | Speciation is the formation of a new species. Isolation can occur due to a physical barrier (E.g. a flood). Conditions on either side of the barrier will be slightly different causing different characteristics to become more common in each population due to natural selection. Eventually, individuals from the different populations will have changed so much that they won't be able to breed with one another to produce fertile offspring. |
| How many pairs of chromosomes are there in a normal human cell nucleus? | 23 pairs. |
| What is an allele. | d |
| What is meant by an organism being heterozygous? | It has two alleles for a particular gene which are both different to each other. |
| What is meant by an organism being homozygous? | It has two alleles for a particular gene which are the same. |
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