Week 9: Phylogenetic Trees I

Question 1

what is another word for evolutionary trees

Answer 1

phylogenetic trees

Question 2

How are family trees & evolutionary trees the same? How are they different?

Answer 2

both represent relationships between different entities, but they differ in the context and the types of relationships they depict.

Similarities:

Both trace ancestry and relatedness.

The farther back in time we go, the more difficult it is to find information.

We can trace common ancestors and find out where certain traits may have come from.

We can use DNA to figure out relationships

Distribution of family members provides clues

Question 3

what is a clade in a family tree

Answer 3

In a family tree, a clade represents a group of individuals who share a common ancestor.

(look at slide 8 for visual representation)

Question 4

How do you know what’s a clade on a family tree

Answer 4

if it takes 1 cut to separate it from the tree (1 branch)

(Look at slide 10 for visual representation)

Question 5

what is a monophyletic clade

Answer 5

a monophyletic clade is a group that represents a single, coherent branch of the tree of life, indicating that all the species or organisms within the clade share a common evolutionary ancestor.

Question 6

what is a polyphyletic clade

Answer 6

a polyphyletic clade is a group that does not include the common ancestor of all its members and, as a result, does not accurately reflect the evolutionary relationships between those organisms. Instead, it groups together organisms that have different, independent evolutionary origins.

Question 7

what is tree thinking

Answer 7

“Tree thinking” is a concept in evolutionary biology and phylogenetics that encourages scientists and researchers to think about the relationships between species in a branching tree-like structure, similar to a family tree.

The idea behind tree thinking is that all species are connected through a series of ancestor-descendant relationships, forming a tree of life. Each branching point on the tree represents a common ancestor, and the tips of the branches represent extant (currently living) species.

Question 8

what is microevolution

Answer 8

Microevolution refers to the small-scale changes in the genetic makeup of a population over a relatively short period of time.

Question 9

what is macroevolution

Answer 9

Macroevolution is the long-term process of large-scale evolutionary changes that occur over extended periods, typically involving the formation of new species and the divergence of major taxonomic groups.

Question 10

what is a population

Answer 10

In biology, a population is a group of individuals of the same species that live in the same geographic area and are capable of interbreeding.

Question 11

How do we read an evolutionary tree?
(review slide 20)

Question 12

what is a root on a evolutionary tree
(review slide 20)

Answer 12

represents the common ancestor from which all the species or lineages depicted on the tree are descended.

Question 13

what do branches on the evolutionary tree represent
(review slide 20)

Answer 13

branches represent the evolutionary relationships between different taxa (species, groups, or lineages). Each branch on the tree represents a lineage, and the points at which branches split or diverge from one another correspond to divergence events or common ancestors.

Question 14

what are nodes on evolutionary tree
(review slide 20)

Answer 14

nodes are the points where branches split or diverge

Question 15

what is a terminal branch on evolutionary tree

Answer 15

A terminal branch, also known as a “tip” on an evolutionary tree represents an individual taxon, such as a species or a group of closely related species, that is currently alive or is a direct descendant of its most recent common ancestor

Question 16

Phylogenies are built on the principle of _________

Answer 16

parsimony (simplicity!)

Occam’s razor (or the principle of
parsimony): when presented with
competing hypotheses that make the same predictions, one should select the solution with the fewest assumptions.

Question 17

when does the principle of parsimony in regards to evolutionary tree doesn’t work

Answer 17

analogous/convergent evolution: refers to the independent evolution of similar traits in different lineages.