Download Ch 26 Guided Reading Key

Chapter 26 – Grading Rubric – 21 pts total
1. Discuss what is meant by “phylogeny”.
1 pt - Phylogeny is the grouping of organisms by their evolutionary relationships.
2. Flying in vertebrates has evolved at least three times (bats, birds, and pteridons). Discuss if flying ability
means that these organisms are closely related and justify your answer.
1 pt - No, they are not closely related although all are vertebrates. Each has different modifications or
adaptations of the bone structure for flight.
3. Define what is meant by convergent evolution and identify at least two examples.
½ pt - Convergent evolution is when two different organisms have similar appearances because they have
similar adaptations to a similar environment.
½ pt each, 1 pt total - Any two acceptable examples.
4. As discussed earlier, genes do not always code for a protein. Describe how the comparison of proteins
between two organisms can still yield data about their evolutionary relationships and justify your answer.
½ pt - The primary sequence of proteins (amino acid sequence) is determined by the codons.
½ pt – Justification - organisms with similar primary protein structure must have very similar DNA codons
and therefore a close evolutionary relationship.
5. Identify and explain whether each of the following pairs of structures more likely represents analogy or
homology:
a) hedgehog quills and a cactus spines
b) a dog’s paw and a human’s hand
c) a bat’s wing and a bird’s wing
½ pt each – 1 ½ pts total
a) Analogy – same function but different origin
b) Homology – same ancestor
c) Homology - if go back to original vertebrate ancestor. Could be argued as Analogy.
6. Species D and E have similar appearances, but different DNA sequences. Species M and N have different
appearances, but very similar DNA. Discuss which pair of species is more likely to be closely related and
justify your answer.
½ pt – species M and N
½ pt – Justification - species with similar DNA will share a more recent common ancestor and will be most
closely related.
7. Explain how base changes could occur in an organism’s DNA yet not affect the organism’s evolutionary
fitness.
1 pt – wobble effect would allow changes in the genetic code to build the same protein. A similar R group
may result in a similar protein. If the protein is the same or very similar, it may not have any effect on
the fitness of the organism.
8. If a particular behavior, such as building nests and caring for the young is found in all members that share a
common ancestor, is it likely that this behavior was also found in the common ancestor? Explain and
justify your answer.
½ pt – Yes
½ pt – Justification - a behavior that is found in all descendents from a common ancestor is unlikely to
have evolved independently that many different times. It is more likely to have been inherited from
the common ancestor.
9. One species shows a trait or behavior that is not found in the other descendent species from the same
common ancestor. Explain how this is possible and justify your answer.
½ pt – the new trait or behavior has likely originated as a novel mutation or a new adaptation of an existing
trait.
½ pt – Justification - it is likely to be of recent origin since it is not shared with other descendent species
From the same ancestor.
10. Identify the Five Kingdoms and describe their chief characteristics.
½ pt identify, ½ pt describe, 5 pts total
Monera – single cell, prokaryotic, heterotrophic or autotrophic
Protista – single or multi- cell, eukaryotic, heterotrophic or autotrophic
Fungi – single or multi- cell, prokaryotic, cell wall present, heterotrophic by external digestion
Plantae – single or multi- cell, eukaryotic, cell wall present, usually autotrophic
Animilia – multi-cell, eukaryotic, no cell wall, heterotrophic by internal digestion
11. Discuss why the Five Kingdoms may soon be replaced by a system that has seven or eight Kingdoms.
1 pt – Kingdom Protista is too broad and needs to be split into several kingdoms. It is not a monophyletic
grouping.
12. Identify and describe the chief characteristics of the Three Domains.
½ pt identify, ½ pt describe, 3 pts total
Bacteria – single cell, prokaryotic, no histones on DNA, circular DNA
Archaea – single cell, prokaryotic, has histones on DNA
Eukarya – single or multi-cell, eukaryotic, linear DNA with histones
13. Based on the characteristics of the 3 Domains, speculate on the likely characteristics of the Common
Ancestor for all Life. (hint –look for features common to all three Domains).
½ pt each, any 2 acceptable answers, 1 pt total
Single cell, prokaryotic, heterotrophic, DNA without histones other acceptable answer
14. The DNA sequences studied for the African Violet “species” found in the Usambaras Mountain area of
Tanzania is so alike that only a very small number of base changes can be detected. Discuss what this data
suggests about the phylogeny of these African Violets and justify your answer.
½ pt – they are very closely related and shared a common ancestor VERY recently.
½ pt – Justification - there is no other way to explain the high degree of similarity in the DNA. They have
to have shared a VERY recent common ancestor. Likely they are still in the process of splitting into
species.