Practise classification by using species concepts, cell evidence and organism features to distinguish domains and kingdoms, interpret taxonomic ranks and classify viral genomes.
Bears are several species of mammal in the family Ursidae.
Climate change and loss of habitats due to human activity have reduced the size of some bear populations in recent years.
Grizzly bears, Ursus arctos horribilis, and polar bears, Ursus maritimus, are found in North America.
Fig. 8.1 shows a grizzly bear and a polar bear.
Grizzly bears have:
- a varied diet that includes grasses, roots, berries, nuts, rodents, insects and fish
- a habitat of woodland or grassland
- a maximum mass of 270 kg .
Polar bears have:
- a diet that consists of other animals, such as seals
- a habitat of land and sea ice
- a maximum mass of 450 kg .
Climate change has caused populations of grizzly bears to spread further north and populations of polar bears to spread further south. In some areas there is habitat overlap and, on rare occasions, breeding between grizzly bears and polar bears has occurred.
The offspring of grizzly bears and polar bears are known as pizzly bears.
Pizzly bears can breed together in the wild.
Fig. 8.2 shows a pizzly bear.
Fig. 8.2
With reference to three different species concepts, discuss whether grizzly bears and polar bears should be classified as separate species.
Genetic technology uses many different enzymes and techniques.
Restriction endonucleases are used in genetic modification. These enzymes occur naturally in prokaryotic cells. More than 3500 different restriction endonucleases have been identified and it is thought there are many more to discover.
Name two domains that are a source of restriction endonucleases.
Describe the biological species concept.
Suggest when the morphological species concept is more useful than the biological species concept.
Compare the characteristics of members of the domain Archaea with the characteristics of members of the domain Bacteria.
Include similarities and differences.