ch 20: Natural Selection

Question 1

Linnaeus

Answer 1

• a botanist who collected and classified objects.

- produced today’s more specific system of classification for plants and animals (taxa).

Question 2

classification

Answer 2

a way of grouping/organizing organisms.

Question 3

Taxonomy

Answer 3

major categories into which organisms are grouped

Question 4

taxon

Answer 4

unit at any level of hierarchy

Question 5

Binomial nomenclature

Answer 5

Linnaeus’s system for naming species

Each species has a Latinized name composed of two words (Bi-nomial) written in italics or underlined.

Question 6

genus

Answer 6

First word is written with a capital initial letter

Question 7

species

Answer 7

2nd word is a lowercase

Question 8

all taxonomies

Answer 8

Kingdom
Phylum
Class
Order
Family
Genus
Species

Katie poured coffee on frank’s green shirt

Question 9

Phylogeny

Answer 9

The evolutionary history of a species or a group of related species

• Use fossils, morphological and molecular evidence
• Constructed by using evidence from systematics - a discipline that focuses on classifying organisms and their evolutionary relationships.

Question 10

phylogenetic trees

Answer 10

Systematists depict evolutionary relationships in branching, A branching diagram, that depicts hypotheses about evolutionary relationships. Depicts common descent of species or higher taxa

A phylogenetic tree represents a hypothesis about evolutionary relationships

Question 11

Homology

Answer 11

character similarities that result from a common ancestry (evolution)

Question 12

differ from Lin and phy

Answer 12

Linnaean classification(resemblances) and phylogeny can differ from each other

Question 13

PhyloCode

Answer 13

which recognizes only groups that include a common ancestor and all its descendants

Question 14

branch point

Answer 14

represents the divergence of two species

Question 15

sister taxa

Answer 15

are groups that share an immediate common ancestor

Question 16

rooted tree

Answer 16

includes a branch to represent the last common ancestor of all taxa in the tree

Question 17

basal taxon

Answer 17

diverges early in the history of a group and originates near the common ancestor of the group

Question 18

polytomy

Answer 18

a branch from which more than two groups emerge

Question 19

What We Can and Cannot Learn from Phylogenetic Trees(3)

Answer 19

• Phylogenetic trees show patterns of descent, not phenotypic similarity
• Phylogenetic trees do not indicate when species evolved or how much change occurred in a lineage
• It should not be assumed that a taxon evolved from the taxon next to it

Question 20

Cladistics

Answer 20

groups organisms by common descent

Question 21

Cladogram

Answer 21

depicts patterns of shared characteristics among taxa and forms the basis of a phylogenetic tree

Question 22

clade

Answer 22

is a group of species that includes an ancestral species and all its descendants

Clades can be nested in larger clades, but not all groupings of organisms qualify as clades

Question 23

monophyletic clade

Answer 23

signifies it consists of the ancestor species and all its descendant’s

Question 24

paraphyletic clade

Answer 24

contains some but all descendants

Question 25

polyphyletic

Answer 25

grouping consists of various taxa with different ancestors

Question 26

shared ancestral character

Answer 26

is a character that originated in an ancestor of the taxon

Question 27

shared derived character

Answer 27

is an evolutionary novelty unique to a particular clade

A character can be both ancestral and derived, depending on the context

Question 28

Inferring Phylogenies Using Derived Characters

Answer 28

When inferring evolutionary relationships, it is useful to know in which clade a shared derived character first appeared

Question 29

outgroup

Answer 29

is a species or group of species that is closely related to the ingroup,

An outgroup is a group that has diverged before the ingroup

Question 30

ingroup

Answer 30

the various species being studied

Question 31

extra in and out-group

Answer 31

Systematists compare each ingroup species with the outgroup to differentiate between shared derived and shared ancestral characteristics

Characters shared by the outgroup and ingroup are ancestral characters that predate the divergence of both groups from a common ancestor

Question 32

Maximum Parsimony

Answer 32

assumes that the most likely tree is the one that requires the fewest evolutionary events (appearances of shared derived characters)

• Systematists can never be sure of finding the best tree in a large data set
• They narrow possibilities by applying the principle of maximum parsimony
• In phylogenies based on DNA, the most parsimonious tree has the fewest base changes
• Computer programs are used to search for trees that are parsimonious

Question 33

Evolutionary history Documented in an organism’s genome(4)

Answer 33

• The rate of evolution of DNA sequence varies from one part of the genome to another.
• Comparing these different sequences helps us to investigate relationships between groups of organisms that diverged a long time ago.
• DNA that codes from Ribosomal RNA Changes relatively slowly – useful for investigating relationships between taxa that diverged hundreds of million years ago.
• DNA that codes for mitochondrial DNA evolves rapidly and can be used to explore recent evolutionary events

Question 34

mol clock

Answer 34

Methods used to measure the absolute time of evolutionary change based on the observation that some genes and other regions of the genome appear to evolve at contestant rates.

Question 35

molecular clock

Answer 35

uses the constant rate of evolution observed in some genes to estimate the absolute time of evolutionary change

Question 36

The number of nucleotide substitutions in related genes is assumed to be _____ to the time since they last shared a common ancestor

Answer 36

proportional

• Molecular clocks are calibrated by plotting the number of genetic changes against the dates of branch points known from the fossil record
• Average rates of genetic change can be used to estimate dates of events not discernable from the fossil record

Question 37

Taxonomy

Answer 37

Used to be two kingdoms Then 5 Now 3 domains

Question 38

Used to be two

Answer 38

Plant, Animals

Question 39

Then 5

Answer 39

Monera, Protista, Plantae, Fungi and Animalia

Question 40

Now 3 domains

Answer 40

Bacteria, Archaea, Eukarya

1. Bacteria- Normal bacteria**
2. Archaea- Hot spring bacteria
3. Eukarya- Everything else’
   - Both of these are prokaryotes