CHAPTER 8

Question 1

who first conceived the theory of evolution

Answer 1

Charles Darwin

Question 2

the four principles of life the evolution is based on

Answer 2

• Many of the traits of an organism are heritable
• Sometimes organisms have heritable traits that are new, not copied from parents =mutation.
• An organisms traits effect how successfully that organism is able to reproduce
• There’s competition for limited resources, allowing only some individuals to reproduce before they die.

Question 3

The theory of evolution combines these four basic principles of life together:

Answer 3

the DIFFERENTIAL SUCCESS of certain VARIATIONS of a HERITABLE trait, because of the COMPETITION for limited resources, leads to change over time (evolution) of that trait.

Question 4

organisms are grouped together based on there most ______

Answer 4

organisms are grouped together based on their most recent shared common ancestor.

Question 5

How can we figure out which dinosaurs share a more recent common ancestor, and, therefore, should be grouped together?

Answer 5

This is done by studying characters.

Question 6

character

Answer 6

A character is any heritable trait that can be described and labeled

Question 7

A shared derived character

Answer 7

A shared derived character is a character that is present in two or more groups and their common ancestor, but is not present in any more distantly related groups.

Question 8

synapomorphy

Answer 8

A shared derived character is also called a synapomorphy.

Question 9

What is one of the biggest challenges to determining evolutionary relationships?

Answer 9

One of the biggest challenges to determining evolutionary relationships is the common phenomenon of convergent evolution.

Question 10

Ouranosaurus

Answer 10

Ouranosaurus is an Iguanodont with a:

• Beak
• Grinding teeth
• Hoofed toes
• Long processes on the vertebrae of the back that form a sail.

Question 11

Spinosaurus

Answer 11

Spinosaurus is a theropod with a:

• Long snout
• Sharp teeth
• Clawed fingers
• Long processes on the - vertebrae of the back that form a sail.

Question 12

convergent evolution.

Answer 12

The evolution of similar traits in two different or separate lineages is termed convergent evolution.

Question 13

parsimony OR Occam’s razor

Answer 13

The idea that “all other things being equal, the simplest answer is usually the right one” is called parsimony. Parsimony is also referred to as Occam’s razor.

Question 14

how to paleontologists determine evolutionary relationships between large numbers of species, many of which may be closely related, and to take into consideration a large number of characters

Answer 14

they use computer programs that analyze a list of characters which is compelled by the researcher.

Question 15

what is the list of characters called

Answer 15

a matrix

Question 16

which principle does the computer apply and why?

Answer 16

the principle of parsimony and its to that they could arrange the sequence of relationships that require the fewest instances of convergence evolution

Question 17

phylogenetic trees

Answer 17

The resulting arrangements look like diagrams of a “family tree” and are called phylogenetic trees.

Question 18

what are the phylogenetic trees composed of ?

Answer 18

nodes and branches

Question 19

what’s a node ?

Answer 19

A node is where two branches diverge, and shows the point at which two linages shared a common ancestor.

Question 20

what’s after the node?

Answer 20

After a node, the pattern of subsequent branches and nodes shows how the descendants of that common ancestor continued to diverge from each other

Question 21

what’s a clade?

Answer 21

A group of species that share a common node is called a clade.

Question 22

what must a clade contain?

Answer 22

A clade must contain the ancestor of a group and all of its descendants. A group that does not include all of the descendants of a common ancestor is therefore not a clade.

Question 23

Linnaean Hierarchy

Answer 23

was formed before ideas like evolution and natural selection. It classifies organisms as belonging to a Kingdom, Phylum, Class, Order, Family, Genus, and Species

Question 24

“missing links”

Answer 24

organisms that show an evolutionary connection between two major groups of organisms by displaying a mosaic of traits and characteristics from both groups.

Question 25

Thomas Henry Huxley

Answer 25

Huxley was also the first scientist to recognize that birds evolved from dinosaurs, and he cited the newly discovered specimens of Archaeopteryx as fossils of a “missing link” between dinosaurs and birds.

• showed that there are transitional forms in the fossil record through studying Archaeopteryx.

Question 26

Archaeopteryx

Answer 26

• Specimens of Archaeopteryx had been found exquisitely preserved in fossil lake deposits
• Long wing feathers and tail feathers like a bird.
• had teeth, clawed fingers, and long series of tail vertebrae just like Dinos do.

Question 27

Sinosauropteryx

Answer 27

Sinosauropteryx was the first non-avian (non-bird) dinosaur to be discovered with feathers

• simple feathers
• used for insulation

Question 28

birds are the only ____ of dinosaurs live today.

Answer 28

clade

Question 29

aves

Answer 29

refer to the crown group of birds, which includes all living birds as well as extinct taxa like the dodo and moa

Question 30

Avialae

Answer 30

generally equivalent to ‘flying dinosaurs’, which includes extinct species that looked very similar to modern birds, including Archaeopteryx.

Question 31

how many definitions are there for birds

Answer 31

4

Question 32

Definition 1

Answer 32

Archaeopteryx and all of its descendants.

Question 33

problem with definition 1

Answer 33

New phylogenetic analyses sometimes show that Archaeopteryx is more closely related to the dromaeosaurid theropods than to modern birds.

Question 34

Definition 2

Answer 34

Feathered dinosaurs.

Question 35

problem with definition 2

Answer 35

As more and more feathered dinosaur fossils, like Yutyrannus, are found, more dinosaur are included in this definition. For instance tyrannosaurs would now be considered birds!

Question 36

defintion 3

Answer 36

Flying dinosaurs.

Question 37

problem with definition 3

Answer 37

It is difficult to determine exactly which dinosaurs were capable of flying (as opposed to simply gliding).

Question 38

defintion 4

Answer 38

Crown dinosaurs. This a somewhat technical term that means the last common ancestor of all extant birds and its descendants.

Question 39

problem with definition 4

Answer 39

This definition fails to recognise many feathered and flying dinosaurs that are more closely related to modern birds than to Archaeopteryx as birds.

Question 40

which definition is favoured by palaeontologists

Answer 40

Definition 4 favoured by many palaeontologists. We then use the name Avialae for the clade containing Archaeopteryx and all of its descendants.