chapter 26 phylogeny & the tree of life
Overview
Phylogenies reveal evolutionary relationships between species. A phylogenetic tree is a branching diagram that presents these relationships visually. They are intended to show patterns of descent. To help classify species and their relatives, binomial nomenclature and hierarchical classification were developed. The picture below portrays this type of categorization for a leopard, called Panthera pardus.
Morphological and molecular data help to construct phylogenies. More similar morphologies or genetic sequences generally means that the organisms are more closely related. Molecular systematics allows scientists to utilize data from DNA and other molecules to determine evolutionary relationships. The identified shared characteristics can be used to construct phylogenetic trees. Maximum parsimony suggests that the simplest explanation/tree consistent with the facts should be investigated first. The principle of maximum likelihood states that certain probability rules about DNA sequences changing over time can help construct a tree with the most likely sequence of events.
Phylogenetic trees serve as hypotheses about evolution that can always be modified and revised. New information continues to revise scientists' understanding of the trees that explain connections between past life and present life.
Phylogenies reveal evolutionary relationships between species. A phylogenetic tree is a branching diagram that presents these relationships visually. They are intended to show patterns of descent. To help classify species and their relatives, binomial nomenclature and hierarchical classification were developed. The picture below portrays this type of categorization for a leopard, called Panthera pardus.
Morphological and molecular data help to construct phylogenies. More similar morphologies or genetic sequences generally means that the organisms are more closely related. Molecular systematics allows scientists to utilize data from DNA and other molecules to determine evolutionary relationships. The identified shared characteristics can be used to construct phylogenetic trees. Maximum parsimony suggests that the simplest explanation/tree consistent with the facts should be investigated first. The principle of maximum likelihood states that certain probability rules about DNA sequences changing over time can help construct a tree with the most likely sequence of events.
Phylogenetic trees serve as hypotheses about evolution that can always be modified and revised. New information continues to revise scientists' understanding of the trees that explain connections between past life and present life.
Big Ideas
1.B.2 Phylogenetic trees and cladograms are graphical representations of evolutionary history that can be tested.
1.D.2 Scientific evidence from many different disciplines supports models of the origin of life.
Artifact
Reading guide below:
1.B.2 Phylogenetic trees and cladograms are graphical representations of evolutionary history that can be tested.
1.D.2 Scientific evidence from many different disciplines supports models of the origin of life.
Artifact
Reading guide below:
ch26_readingguide.pdf | |
File Size: | 937 kb |
File Type: |
Helpful video below:
Reflection
What I remember most about this chapter is the mnemonic for hierarchical classification, which goes like this: Dear King Philip Came Over For Good Spaghetti or like this: Dumb King Philip Came Over For Great Sex. The first version is also on the reading guide. Although I never actually had to use the mnemonic, it was fun to learn in class and will probably stay in my memory for a very long time. The reading guide was quite a simple one for this chapter and aided my understanding of cladistics. The video from the Bozeman Science channel, however, was even more helpful to understand how to organize organisms based on their evolutionary relationships. Mr. Anderson's videos are so helpful!
Study Tool
What I remember most about this chapter is the mnemonic for hierarchical classification, which goes like this: Dear King Philip Came Over For Good Spaghetti or like this: Dumb King Philip Came Over For Great Sex. The first version is also on the reading guide. Although I never actually had to use the mnemonic, it was fun to learn in class and will probably stay in my memory for a very long time. The reading guide was quite a simple one for this chapter and aided my understanding of cladistics. The video from the Bozeman Science channel, however, was even more helpful to understand how to organize organisms based on their evolutionary relationships. Mr. Anderson's videos are so helpful!
Study Tool
chapter 27 bacteria & archaea
Overview
Prokaryotes are mostly small and unicellular. They have various shapes, as shown below.
Prokaryotes are mostly small and unicellular. They have various shapes, as shown below.
Bacteria have cell surface structures that protect them. Peptidoglycan is a polymer of sugars cross-linked by polypeptides. Gram-positive bacteria have simple walls with a lot of peptidoglycan and stain purple, while Gram-negative bacteria have more complex walls and less peptidoglycan, staining pink. Prokaryotes also have sex pili, appendages that allow for cells to come together and transfer DNA. Flagella help prokaryotes move around.
Rapid reproduction, mutation, and genetic recombination promote genetic diversity in prokaryotes and speedy adaptation. Since prokaryotes replicate so fast they have short generation times, large populations, and fast mutation rates, which leads to quick proliferation and evolution of better equipped cells. Genetic recombination occurs through movement of genetic material among species. Transformation is when foreign DNA is taken up from the environment. Transduction is when phages carry prokaryotic genes from one host to another. Conjugation is when DNA transfer occurs between two prokaryotes that temporarily join via sex pili.
Big Ideas
3.C.2 Biological systems have multiple processes that increase genetic variation.
Artifact
Find the reading guide for Chapter 27 below:
Rapid reproduction, mutation, and genetic recombination promote genetic diversity in prokaryotes and speedy adaptation. Since prokaryotes replicate so fast they have short generation times, large populations, and fast mutation rates, which leads to quick proliferation and evolution of better equipped cells. Genetic recombination occurs through movement of genetic material among species. Transformation is when foreign DNA is taken up from the environment. Transduction is when phages carry prokaryotic genes from one host to another. Conjugation is when DNA transfer occurs between two prokaryotes that temporarily join via sex pili.
Big Ideas
3.C.2 Biological systems have multiple processes that increase genetic variation.
Artifact
Find the reading guide for Chapter 27 below:
ch27_readingguide.pdf | |
File Size: | 894 kb |
File Type: |
Reflection
The reading guide for this chapter helped me to organize essential information in my memory. Like every other reading guide. They are just helpful ways to process information. That is probably why teachers like to assign them to students. Of course, they take a while to complete, which can make it hard for students with tight schedules to utilize in the best way possible. In general, the benefits of the reading guides are numerous and the one on bacteria and archaea proved to be a considerable aid while studying.
Study Tools
The reading guide for this chapter helped me to organize essential information in my memory. Like every other reading guide. They are just helpful ways to process information. That is probably why teachers like to assign them to students. Of course, they take a while to complete, which can make it hard for students with tight schedules to utilize in the best way possible. In general, the benefits of the reading guides are numerous and the one on bacteria and archaea proved to be a considerable aid while studying.
Study Tools
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