Week 7

Question 1

All living creatures struggle to ____ and to _____.

Answer 1

All living creatures struggle to survive and to reproduce.

Question 2

Natural selection

Answer 2

The struggle to survive and the natural variability among individuals results in some individuals being more likely to produce offspring. Therefore, those traits get passed on.

Question 3

The accumulation of multiple small changes over time can cause

Answer 3

changes within a species, form new species, or cause a loss of species.

Question 4

Biological Species

Answer 4

A group of individuals that actually or potentially interbreed in nature and produce more fertile offspring.

Question 5

Linnaean Taxonomy

Answer 5

Carolus Linnaeus

Kingdom; phylum; class; order; family; genus; species

Hierarchical system ranks groups of organisms into successively smaller categories. Smaller groups are defined by more specific, unique characteristics.

The more features you have in common, the more closely related you are going to be.

A taxon can refer to a group at any rank.

Question 6

Homologous Structures

Answer 6

Features are inherited by an ancestor.

If two organisms share a feature, they may have inherited it from a common ancestor.

Question 7

Analogous Structure

Answer 7

Features in two different organisms look similar because they serve a similar function, but they are not as a result of a common ancestor.

This is an example of convergent evolution: a structure that was not inherited, shows up independent of similar structures because they live similar lifestyles.

Question 8

Phylogenetic Systematics

Answer 8

Evolutionary Trees: allows us to draw out how organisms have gradually changed over time.

How closely related two creatures are is determined using characters: observable features of anatomy.

Homologous characters.

Some homologous characters will be considered diagnostic depending on the group you are identifying. (eg. fur is diagnostic of mammals, but not dogs).

Question 9

Diagnostic Characters

Answer 9

Distinctive and unique characters which define a taxon.

Question 10

Cladograms

Answer 10

Branching diagrams that show hierarchies of diagnostic characters

A hypothesis that shows how to organisms are potentially related to each other

Not an evolutionary tree as time is not represented in a cladogram

The cladogram that is most correct is the one that does not change when new characters are added.

Everything above the node must have that feature in common.

Question 11

Principle of Parsimony and how it relates to cladograms

Answer 11

The simplest explanation is often the best

The correct cladogram is often the one with fewest evolutionary steps

Question 12

Characters that appear low on a cladogram are considered

Answer 12

primitive.

Question 13

Evolved, new characters that appear farther up the cladogram are considered

Answer 13

derived characters.

Question 14

By mapping out hierarchical distribution of characters cladograms allow us to hypothesize

Answer 14

the evolutionary relationships among organisms.

Question 15

When mapping the course of evolution you will notice three things about each group of animals

Answer 15

1. Each has its own distinct history (lineage, represented by branches on the cladogram)
2. They share a part of their history
3. Somewhere back in time they shared a common ancestor (point of common ancestry is at the node)

Question 16

Common ancestry is the ____ for determining how closely organisms are related.

Answer 16

Common ancestry is the basis for determining how closely organisms are related.