Phylogeny and History of Life - Ch. 20

Question 1

Systematic

Answer 1

the field that scientists use to organize and classify organisms based on evolutionary relationships. Researchers may use data from fossils, from studying the body part structures, or molecules that an organism uses, and DNA analysis.

Question 2

Taxonomy

Answer 2

the science of classifying organisms to construct internationally shared classification systems with each organism placed into increasingly more inclusive groupings.

Question 3

What is the order of the classification of life?

Answer 3

kingdom, phylum, class, order, family, genus, species

Question 4

Binomial nomenclature

Answer 4

two-word specific name of an organism. It takes up genus and species. Both are italicized but the species is not capitalized while the genus is.

Question 5

Phylogeny

Answer 5

evolutionary history and relationship of an organism or group of organisms. A phylogeny describes the organism’s relationships, such as from which organisms it may have evolved, or to which species it is most closely related. Phylogenetic relationships provide information on shared ancestry but not necessarily on how organisms are similar or different.

Question 6

Ancestral lineage

Answer 6

all organisms represented in the diagram relate to one ancestor

Question 7

Branch point

Answer 7

when a split occurs in a phylogenetic tree, it represents where a single lineage evolved into a distinct new one.

Question 8

Most recent common ancestor

Answer 8

We can trace the pathway from the origin of life to any individual species by navigating through the evolutionary branches between the two points. Also, by starting with a single species and tracing back towards the “trunk” of the tree, one can discover species’ ancestors, as well as where lineages share a common ancestry. In addition, we can use the tree to study entire groups of organisms.

Question 9

Basal taxon

Answer 9

a lineage that evolved early from the root that remains unbranched

Question 10

Sister taxa

Answer 10

two lineages stemming from the same branch point

Question 11

Polytomy

Answer 11

A branch with more than two lineages and serves to illustrate where scientists have not definitively determined all of the relationships.

Question 12

What should be noted for sister taxa and polytomy?

Answer 12

although sister taxa and polytomy do share an ancestor, it does not mean that the groups of organisms split or evolved from each other. Organisms in two taxa may have split at a specific branch point, but neither taxon gave rise to the other.

Question 13

What are the different categories of branch lengths?

Answer 13

genetic change or time

Question 14

Homologous structures

Answer 14

have the same structure of a body part, like an arm, but all differ in structure. For example, the lizard’s arm is for digging and the bird’s arm is for flying.

Question 15

Divergent evolution

Answer 15

two species that evolve in diverse directions from a common point

Question 16

Homologies

Answer 16

Similarities between organisms can stem either from shared evolutionary history

Question 17

Analogies structures

Answer 17

The structure of a body part is different but the function of it is the same. For example, the turtle and fish fin are completely different in structure, yet they both serve to help the animal swim

Question 18

Convergent evolution

Answer 18

independently in species that do not share a common ancestry

Question 19

Analogies

Answer 19

Similarities between organisms can stem from separate evolutionary paths

Question 20

Cladogram

Answer 20

diagram that depicts patterns of a shared characteristic among groups

Question 21

Clade

Answer 21

groups of a species that includes an ancestral species and all descendants

Question 22

Phylogenetic tree

Answer 22

branching diagram that shows evolutionary history of a group of organisms

Question 23

Principle of maximum parsimony

Answer 23

use the simplest explanation (fewest DNA changes) to construct phylogenetic trees

Question 24

Molecular clock

Answer 24

measure evolutionary change based on regions of genome change based on regions of genome that appeal to evolve at constant rates
used to estimate dates of past evolutionary events

Question 25

Tree of life

Answer 25

3 domains of life consisting of bacteria, archaea, and eukarya. There is a common ancestor among all three domains.

Question 26

Characteristics of all life forms

Answer 26

All domains have DNA and RNA as carriers of genetics, universal genetic code, and conserved metabolic pathways.

Question 27

Characteristics of all eukaryotes

Answer 27

all eukaryotes have a cytoskeleton, membrane-bound organelles, linear chromosomes, and endomembrane systems