Chapter 25 - Phylogenies and the History of Life

Question 1

What is a phylogeny?

Answer 1

A phylogeny is the evolutionary history and relationships among species or groups of organisms.

Question 2

True or False: Phylogenies are only based on morphological characteristics.

Answer 2

False

Question 3

Fill in the blank: The study of evolutionary relationships is called _______.

Answer 3

phylogenetics

Question 4

What is a common ancestor?

Answer 4

A common ancestor is an ancestral species from which multiple species have evolved.

Question 5

Which of the following is used to construct phylogenetic trees? (A) DNA sequences (B) Morphological traits (C) Fossil records (D) All of the above

Answer 5

D) All of the above

Question 6

What does a phylogenetic tree illustrate?

Answer 6

A phylogenetic tree illustrates the evolutionary relationships and divergence among species.

Question 7

True or False: Clades are groups of organisms that include an ancestor and all its descendants.

Answer 7

True

Question 8

What is the term for a branching diagram that represents the evolutionary relationships among organisms?

Answer 8

Phylogenetic tree

Question 9

Fill in the blank: The _______ is the point in a phylogenetic tree where two lineages diverge.

Answer 9

node

Question 10

What are homologous structures?

Answer 10

Homologous structures are anatomical features in different species that share a common ancestry.

Question 11

Which type of data is commonly used to infer phylogenies?

Answer 11

Molecular data such as DNA sequences.

Question 12

True or False: Convergent evolution can complicate the construction of phylogenetic trees.

Answer 12

True

Question 13

What is the primary goal of constructing a phylogenetic tree?

Answer 13

To depict the evolutionary relationships among a group of organisms.

Question 14

Which software is commonly used for phylogenetic analysis?

Answer 14

MEGA (Molecular Evolutionary Genetics Analysis)

Question 15

What is the significance of a rooted phylogenetic tree?

Answer 15

A rooted tree shows the most recent common ancestor of all the taxa represented.

Question 16

Fill in the blank: The process by which species evolve to become more different over time is called _______.

Answer 16

divergent evolution

Question 17

What is a sister group in phylogenetics?

Answer 17

Sister groups are the closest relatives on a phylogenetic tree that share a common ancestor.

Question 18

What does the term ‘monophyletic’ refer to?

Answer 18

A monophyletic group includes an ancestor and all its descendants.

Question 19

True or False: Paraphyletic groups include some, but not all, descendants of a common ancestor.

Answer 19

True

Question 20

What is the difference between homologous and analogous structures?

Answer 20

Homologous structures arise from a common ancestor, while analogous structures arise from convergent evolution.

Question 21

Which method is used to determine the most likely phylogenetic tree among a set of species?

Answer 21

Maximum likelihood estimation

Question 22

What is the role of fossils in phylogenetics?

Answer 22

Fossils provide historical evidence of evolutionary changes and relationships.

Question 23

Fill in the blank: The _______ principle states that the simplest explanation is preferred when constructing phylogenies.

Answer 23

Occam’s razor

Question 24

What is the purpose of molecular clocks in phylogenetics?

Answer 24

Molecular clocks estimate the time of divergence between species based on genetic mutations.

Question 25

True or False: Phylogenetic trees can change with new scientific evidence.

Answer 25

True

Question 26

What does 'bootstrap analysis' provide in phylogenetics?

Answer 26

Bootstrap analysis provides a measure of support for the branching patterns in a phylogenetic tree.

Question 27

Fill in the blank: The _______ is the common ancestor of all life forms.

Answer 27

last universal common ancestor (LUCA)

Question 28

What is a phylogenetic network?

Answer 28

A phylogenetic network is a graph that represents multiple potential evolutionary pathways among species.

Question 29

Which type of data can lead to conflicting phylogenetic trees?

Answer 29

Incomplete lineage sorting

Question 30

True or False: The concept of species is always clear and universally agreed upon among biologists.

Answer 30

False

Question 31

What is the significance of the Cambrian explosion in the history of life?

Answer 31

The Cambrian explosion marks a rapid diversification of life forms and the appearance of most major animal phyla.

Question 32

Fill in the blank: The _______ hypothesis suggests that life originated from simple organic compounds on early Earth.

Answer 32

abiogenesis

Question 33

What does the term 'phylogeography' refer to?

Answer 33

Phylogeography studies the historical processes that may be responsible for the contemporary geographic distributions of individuals.

Question 34

What is the significance of ribosomal RNA in phylogenetics?

Answer 34

Ribosomal RNA sequences are highly conserved and useful for inferring evolutionary relationships across diverse organisms.

Question 35

True or False: All phylogenetic trees are drawn to scale.

Answer 35

False

Question 36

Fill in the blank: The _______ tree represents the evolutionary relationships of organisms without regard to time.

Answer 36

unrooted

Question 37

What does 'speciation' mean?

Answer 37

Speciation is the process by which new species arise from existing ones.