Classification Flashcards
What is meant by a hierarchy?
Groups within groups with no overlaps between them.
Explain the role of independent segregation in meiosis
Independent segregation results in genetic variation and allows different combinations of maternal and paternal alleles. It also produces haploid chromosomes by homologous chromosomes lining up randomly at the equator and separate.
A zedonk is the offspring produced from breeding a mountain zebra with a donkey.
• The body cells of a mountain zebra contain 32 chromosomes.
• The body cells of a donkey contain 62 chromosomes.
Use this information to suggest why zedonks are usually infertile.
Zedonks would have 47 chromosomes. This would not be able to form a haploid cell as there is an odd number of chromosomes so they cannot pair up.
What is a species?
A group of organisms that have similar features and are able to reproduce to form fertile offspring.
A forest was cleared to make more land available for agriculture.
After the forest was cleared the species diversity of insects in the area decreased. Explain why.
Fewer plant species, therefore fewer habitats and variety of food. Forest clearing may include the use of pesticides. This results in killing insects so there is also fewer insect species.
Leopards, cheetahs and pumas are all members of the family Felidae.
Biologists used DNA hybridisation to investigate the evolutionary relationships between leopards, cheetahs and pumas. They found that hybrid DNA from a leopard and a cheetah separated into single strands at a higher temperature than hybrid DNA from a leopard and a puma.
These results suggest that leopards are more closely related to cheetahs than to pumas. Explain why.
The results of the test suggests that there are more hydrogen bonds to break between the cheetah and leopard DNA than the leopard and puma as it requires more energy to separate the two strands of DNA. This can be interpreted to be due to more bases hydrogen bonding between the strands- suggesting more bases are complementary in the leopard/cheetah hybrid DNA; thus helping us conclude that they have more similar alleles than puma/leopard and DNA sequence.
All modern cheetahs are thought to have descended from a single female. This female was part of a small population that survived an ice age a long time ago that killed almost all cheetahs. After the ice age, the number of cheetahs increased.
(i) Use this information to explain what is meant by a genetic bottleneck.
A genetic bottleneck is an incident that changes the external environment/habitat of organisms that results in mass death of a population and reduces genetic variation/size of the gene pool.
(ii) The fertility of cheetahs is low. The proportion of abnormal sperm cells produced is higher in cheetahs than in other members of the family Felidae. Suggest an explanation for this.
A mutation may have occurred due to errors in mitosis that affected the code for sperm cells. Since there is a small population and a high likelihood of inbreeding, there is a high chance of inheriting the faulty allele as this results in a high frequency of the faulty allele.
Hummingbirds belong to the order Apodiformes. One genus in this order is Topaza.
Name one other taxonomic group to which all members of the Apodiformes belong.
Kingdom- Animalia
Name the taxonomic group between order and genus.
Family
Explain how the standard deviation helps in the interpretation of data.
SD shows the spread of data about the mean. It can also be used to determine the significance of changes as overlapping SDs suggests that there is no significant difference.
A low SD indicates a more reliable result.
The biologists analysed the amino acid sequences of the blood protein samples from hummingbirds.
Explain how these sequences could provide evidence as to whether the crimson topaz and the fiery topaz are different species.
Different species would have different amino acid sequences. This sequence is determined by DNA base sequence.
Abdominal pumping increases the efficiency of gas exchange between the tracheoles and muscle tissue of the insect. Explain why.
This mixes up the gases inside the
