Chapter 10: Classification and Evolution

Question 1

What is the order of the taxonomic groups?

Answer 1

• Domain
• Kingdom
• Phylum
• Class
• Order
• Family
• Genus
• Species

Question 2

What are heterotrophic feeders?

Answer 2

• Acquire nutrients by ingestion of other organisms.

Question 3

What are autotrophic feeders?

Answer 3

• Acquire nutrients through photosynthesis.

Question 4

What are saprophytic feeders?

Answer 4

• Acquire nutrients through absorption from dead/decaying materials.

Question 5

What is the 3 domain system + how does it group organisms?

Answer 5

• Archae.
• Eukarya –> groups eukaryotes together.
• Bacteria.

Groups organisms based on:

• Differences in RNA nucleotide sequence.
• Cells’ membrane lipid structure.
• Sensitivity to antibiotics.
• Reflects difference between eubacteria + archaebacteria.
• Accurately reflects origins of eukaryotes + prokaryotes.

Question 6

What are the six kingdoms?

Answer 6

• Archaebacteria –> single-celled ancient bacteria.
• Eubacteria –> true bacteria with peptidoglycan cell walls.
• Protoctista
• Animalia
• Fungi
• Plantae

Question 7

Define phylogeny and explain how phylogeny is related to classification.

Answer 7

• Name given to the evolutionary links between organisms.
• Study of closeness between evolutionary relationships..
• Basis of modern classification.
• The closer the evolutionary link, the closer the taxonomic group.

Question 8

Describe fossil formation.

Answer 8

1. Over long periods of time, sediment deposited to form layers (strata) of rock.
2. Each layer corresponds to a different geological era, with the most recent layer being found at the top.
3. Within the different rock strata different fossils found, forming sequence from oldest to youngest.
4. Older –> less complex.
5. Younger –> more complex.
6. Organisms have evolved to become more complex over time.

Question 9

How does fossil record support idea that evolution has taken place?

Answer 9

• Fossils show that organisms have changed over time.
• Fossils can be dated.
• Fossils show sequences from old to young.

Question 10

Define homologous structure.

Answer 10

• A structure that may appear superficially different + perform different functions in different organisms but has the same underlying structure.

Question 11

Outline divergent evolution.

Answer 11

• From a common ancestor, different species have evolved, each with a different set of adaptations to their environments/selection pressures.
• Closely related species adapt to new habitats due to migration or natural disasters.

Question 12

How do comparative biochemistry + anatomy show evidence of evolution?

Answer 12

• Similarities/differences in genes/DNA/RNA/molecules/biochemistry.
• Similarities/differences in base/nucleotide sequence.
• Similarities/differences in Hb/cytochrome C/ATP synthase/RNA polymerase.
• Similarities/differences in amino acid sequence.
• Similar genes –> common ancestor.
• Comparison of anatomy.
• Evolution within human history.

Question 13

Describe continuous variation.

Answer 13

• Effect of many genes.
• Characteristic that can take any value within a given range.
• Has environmental effect.
• E.g. body mass, height.
• Quantitative –> has intermediate values (represented with line graph, usually bell shaped).

Question 14

Describe discrete variation.

Answer 14

• Effect of one gene.
• Little/no environmental effect.
• Discrete categories –> no intermediates,
• E.g. blood type, sex, shape.
• Represented with pie chart or bar graph.

Question 15

Adaptations of marram grass.

Answer 15

• Curled leaves –> reduce s.a. of moist tissue exposed to air + protect leaves from wind.
• Hairy leaves –> trap warm moist air –> reduce water vapour potential gradient.
• Stomata sunk in pits –> less likely to open + lose water in transpiration.
• Thick waxy cuticle on leaves + stems –> reduce water loss by evaporation.

Question 16

Define analogous structures.

Answer 16

• Structures that have evolved to perform same function but have different origin.

Question 17

Outline convergent evolution.

Answer 17

• Unrelated species share similar characteristics.
• Different species adapted to similar environments or selection pressures.
• Similar species because they have adapted to fill similar niches.

Question 18

Describe the steps of natural selection.

Answer 18

1. Mutation –> leads to genetic variation within a species –> changes in base sequence + amino acid sequence.
2. Exposed to new selection pressures + changes in environment (e.g. pest pop. predation, competition).
3. Those with most advantageous allele adapt + survive passing on advantageous allele to offspring.
4. Less adapted die out + do not pass alleles to offspring.
5. Process repeats over many generations.
6. Increase in allele frequency of advantageous allele in gene pool + decrease for less advantageous allele.

Question 19

How to determine if two organisms are of same species or different species.

Answer 19

1. Interbreed.
2. Check for fertile offspring –> same species.
3. If infertile offspring –> different species.

Question 20

How does the phylogenetic approach to classifying species differ from the biological species concept?

Answer 20

Phylogenetic approach:

• no need to test for interbreeding.
• common ancestors.
• applies to organisms that reproduce asexually.
• apply to extinct organisms/fossils.