Questions and Answers
What are the evolutionary relationships among bears?
Researchers have long debated different hypotheses for the phylogeny and classification of species in the bear family, Ursidae.
Which branch point represents the most recent common ancestor of all bears?
branch point 1
Which branch point represents the most recent common ancestor of the sloth bear and the spectacled bear?
branch point 2
Which branch point represents the most recent common ancestor of the Asian black bear and the brown bear?
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Which species is the basal taxon in this tree?
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Identify the sister taxon to the polar bear.
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According to this tree, is the sun bear more closely related to the sloth bear or the polar bear?
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What does it mean if the phylogenetic tree is rooted?
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Which of the following groups of species is a monophyletic group, or clade?
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How should the portion of the tree extending from branch point 7 be altered?
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What kind of group do brown bears plus ancestral species 7 represent?
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Prokaryotic cells are found in the domain(s) _____.
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In the five-kingdom system, prokaryotes are placed in the kingdom _____.
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A human is classified in domain _____ and kingdom _____.
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A rose bush is classified in domain _____ and kingdom _____.
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In the five-kingdom system, which kingdom consists primarily of unicellular eukaryotes?
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In the two-kingdom system, why were fungi classified in the kingdom Plantae?
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There is(are) _____ eukaryotic domain(s).
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Animals that possess homologous structures probably _____.
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Study Notes
Evolutionary Relationships among Bears
- The bear family is scientifically classified as Ursidae.
- Complete mitochondrial DNA (mtDNA) genome sequences were obtained for eight living bear species in 2008.
- A phylogenetic tree was constructed based on the mtDNA data.
Phylogenetic Tree Insights
- Branch point 1 indicates the most recent common ancestor of all bears.
- Branch point 2 represents the common ancestor of the sloth bear and the spectacled bear.
- Branch point 4 shows the common ancestor of the Asian black bear and the brown bear.
Taxonomic Relationships
- The giant panda is the basal taxon in the bear phylogenetic tree.
- The brown bear is identified as the sister taxon to the polar bear.
- The sun bear is more closely related to the polar bear than to the sloth bear.
Characteristics of the Phylogenetic Tree
- The tree is rooted, with the leftmost branch point representing the most recent common ancestor of all bear taxa.
Monophyletic and Paraphyletic Groups
- A clade comprising the sun bear, Asian black bear, American black bear, and two ancestral species is a monophyletic group as it includes a common ancestor and all descendants.
- Brown bears and ancestral species 7 form a paraphyletic group, as they share a common ancestor with polar bears but exclude these descendants.
Prokaryotic and Eukaryotic Domains
- Prokaryotic cells are classified in the domains Bacteria and Archaea.
- In the five-kingdom system, prokaryotes are categorized under the kingdom Monera.
- Humans are classified in the domain Eukarya and kingdom Animalia, while rose bushes fall under Eukarya and Plantae.
- The kingdom Protista is primarily composed of unicellular eukaryotes, though it includes multicellular algae.
Historical Classification Systems
- Fungi were formerly classified under the kingdom Plantae in the two-kingdom system due to their sedentary nature.
Eukaryotic Domains
- There is only one eukaryotic domain, which is Eukarya.
Evolutionary Biology Concepts
- Animals with homologous structures likely evolved from a common ancestor, highlighting the concept of common ancestry in evolutionary biology.
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Description
Test your knowledge on the evolutionary relationships among bears with these flashcards. This assignment focuses on the phylogeny and classification of the bear family, Ursidae, utilizing mitochondrial DNA genome sequences and phylogenetic trees.
