1. A Framework For Studying Animal Diversity

Question 1

What characteristics generally make an animal? 7

Answer 1

1. Multicellular 2. Get energy by eating other organisms. The exception is carnivorous plants. 3. Ability to move except carnivorous plants 4. Asymmetric gametes, larger egg than sperm. However, some animals don’t have distinct gametes 5. Epithelial cells, important in blastula formation 6. The epithelial cells form flexible sheets of epithelia that line body cavities and surfaces. 7. No rigid cell wall

Question 2

What is the taxonomy of animals? 6

Answer 2

1. Provides the most precise definition of what an animal is. 2. Organisms are named 3. Doesn’t necessarily involve relationships or classification 4. May define groups or organisms based on similar traits 5. Categories created are taxa (s)/taxon (pl) 6. eg. order, family, genus, species

Question 3

What is the importance of animal classification? 4

Answer 3

1. Shows evolutionary relationships with other species 2. Helps us understand their behaviour, ecology, form and function 3. Provides common language for communication between scientists 4. Without a picture of ancestry, we can’t say why an animal does mechanical things, only how they do them

Question 4

What is animal classification? 3

Answer 4

1. Hierarchy of groups 2. Moving up the levels merges groups 3. Done by using evolutionary relationships that are revealed by patterns in homologous features

Question 5

What are homologous traits? 3

Answer 5

1. Features of organisms that are due to sharing of common ancestors 2. Now, we also used shared DNA sequences 3. eg. bats and birds share long bones

Question 6

What are analogous traits? 3

Answer 6

1. Similarities between organisms that weren’t present in the last common ancestor of the taxa 2. Evolved separately eg. bat and bird wings 3. An example of convergent evolution

Question 7

What is systematics? 3

Answer 7

1. Taxonomy plus phylogenetics 2. Organises based on common ancestors and creates phylogenies 3. Began after work of Darwin

Question 8

What is phylogenetics? 1

Answer 8

1. The evolutionary history/relationships between organisms

Question 9

Describe classical animal classifications. 3

Answer 9

1. Genesis claims that after God created the animals, Adam named them all. 2. Aristotle (384-322 BC) wrote History of Animals and thought of simple categories for the animals.

Question 10

Who was Carl Linnaeus and how was he involved with binomal naming? 5

Answer 10

1. Lived 1707-17778
2. Was considered part of the birth of modern taxonomy
3. Founded binomal naming system (Genus species), as previous taxonomy was complex and inconsistent
4. Many species’ names come from his work, incl. Systema Naturae and Species Plantarum
5. He thought species were immuntable and used taxonomy to rationalise the order created by God

Question 11

How did Darwin and Wallace collaberate, and what were the differences and similarities between them? 5

Answer 11

1. Darwin was a gentleman’s scientist who sailed on HMS Beagle, 1831-1836
2. Wallace was a specimen collector for money who went to Brazil (1848-1852), Malaysia and Indonesia (1854-1862).
3. Wallace wrote to Darwin, who realised they had similar ideas, and arranged to have one paper each read at the Linnaean Society, 1858.
4. Dawrin believed evolution was due to competition, while Wallace emphasised environment
5. Darwin published On the Origin of Species in 1859, containing only one figure, an example of an ancestral tree.

Question 12

What was the imapct of Darwin’s work? 4

Answer 12

1. Suggested species were mutable
2. Impaced on animal classification, leading to birth of systematics
3. Homology rather than structural/funtional similarity was emphasised, building on the diea of being derived from the same common ancestor
4. This, plus mendelian genetics, caused the demise of Lamarkism

Question 13

How do scientists see the debate between Thomas Huxley and Bishop Wilberforce? 4

Answer 13

1. Debate at Oxford Universtiy museum in 1860.
2. Huxley challenegd the public idea of creationsism and literal belief in the old testament
3. There was a frienyl rivalry between the two
4. Chruch memebrs began to see that they were being unreasonable

Question 14

What is the significance of archeopteryx? 3

Answer 14

1. Transitional form with reptilian and bird-like features
2. Found in museum by Huxley, who realised it was a “missing link”
3. Teeth and tail of reptiles, feathers and wings of birds.

Question 15

What was pangenesis? 3

Answer 15

1. Darwin’s belief of the mechanism of inhertiance
2. Had no knowldge of genes, but believed in ‘gemmules’, small, hereditary particles, with no evidence.
3. These were, in his view, produced by cells and would gather at the reproductive organs and pass on to the offspring

Question 16

Who was Mendel? 2

Answer 16

1. Experiemnts with pea plants eventually shpwed existance of genes
2. Mendals law of inheritance was combinedwith Darwin’s ideas in approx, 1930s

Question 17

What is sexual selection? 3

Answer 17

1. Darwin’s theory for non-advantageous traits, as explained in The Descent of Man, and Selection in Relation to Sex, 1871
2. Zahavi (1975) explained that the traits must be an honest indicator of the animal’s fitness
3. ‘The Handicap Principle’ - animal must be fit to support handicap

Question 18

Explain William Hamilton’s work on altruistic behaviour. 4

Answer 18

1. Theorteical work led to ‘kin selection/Hamilton’s rule’
2. Helped development of a gene-centric view of evolution
3. Explained in The Selfish Gene and The Extended Phenotype (Dawkins)
4. He was the only scientist to make a major advance on Origin.

Question 19

What is biogeography? 3

Answer 19

1. Founded by Wallace
2. Studies geographical distribution of animals and plants
3. The Wallace Live, which separates faunas in Europe, Asia and Australasia, was named after him

Question 20

Give the biological units of classification, with examples.

Answer 20

Question 21

What is a species? 2

Answer 21

1. A biological concept
2. Natural populations that can interbreed with each other but not other groups (Mayr, 1999)

Question 22

What problems are there with the bioloigical definition of a species? 5

Answer 22

1. Some animals don’t reproduce sexually eg. Timema stick insects and rotifers
2. Reproductive criteria can’t really be tested for extinct animals
3. It’s not always known if morphologically similar groups can physically interbreed.
4. Populations can be isolated, leading to a lack of gene exchange between similar organisms
5. As for ring species, some species that aren’t adjacent can’t interbreed.

Question 23

Why do some animals seem to have adaptations that aren’t as helpful as they could be? 3

Answer 23

1. Form and funciton must compromise
2. Contained by evolutionary history
3. eg. rotation is better for flying than flapping but impossible due to joint

Question 24

Is animal classification permanent? 2

Answer 24

1. No - aparticular group can change positions due to phylogeny/evidence used
2. Can make some groups appear more related than previously thought.