Midterm 1

Question 1

Laggerstatten

Answer 1

A site with abundant supply of unusually well-preserved fossils from the same period of time, often including soft tissues

Question 2

Burgess Shale

Answer 2

A laggerstatten in Canada that preserved fossils from the Cambrian period like that weird spiky animal

Question 3

Biomarker

Answer 3

Molecular evidence of life in the fossil evidence. This can include chemicals like Okenone that can only be created by living organisms

Question 4

Stromatolites

Answer 4

Layered structures formed by the mineralization of bacteria (Large rock like mounds)

Question 5

Ediacaran fauna

Answer 5

A group of animal species that existed between 575 and 535 mya (before the Cambrian period)

Question 6

Chordates

Answer 6

Members of a diverse phylum that includes vertebrates, lancelets, and tunicates. They all have a notochord which is a hollow nerve chord, gill slits, and a post anal tail as embryos

Question 7

Trilobites

Answer 7

Now extinct marine arthropods that diversified during the Cambrian period and gradually died out during the Devonian

Question 8

Prokaryotes

Answer 8

Organisms lacking a nucleus, or any other membrane bound organelles. They include Archaea as well

Question 9

Tetrapods

Answer 9

Vertebrates with four limbs. Living tetrapods include mammals, birds, reptiles and amphibians

Question 10

Teleosts

Answer 10

A lineage of bony fish that comprise most living species of vertebrates. They include goldfish, salmon, and tuna. They can be distinguished from other fishes by unique traits like the mobility of an upper jawbone

Question 11

Synapsids

Answer 11

A lineage of tetrapods that emerged 300 million years ago and gave rise to mammals

Question 12

Hominin

Answer 12

Humans and all species more closely related to humans than to Chimpanzees

Question 13

Phylogeny

Answer 13

A visual representation of the evolutionary history of populations, genes, or species

Question 14

Tips of a phylogeny/tree

Answer 14

The terminal ends of an evolutionary tree representing species, molecules, or populations being compared

Question 15

Branches

Answer 15

Lineages evolving through time between successive speciation events

Question 16

Node

Answer 16

A point in a phylogeny where a lineage splits (speciation!)

Question 17

Internal nodes

Answer 17

Nodes within a phylogeny representing ancestral populations or species

Question 18

Clade

Answer 18

An organism and all of its descendants

Question 19

Monophyletic

Answer 19

A term used to describe a group of organisms that form a clade

Question 20

Characters

Answer 20

Heritable aspects of organisms that can be compared across taxa

Question 21

Taxon (Taxa)

Answer 21

A group of organisms that a taxonomist judges to be a taxonomic unit like a species or an order. (Depends on what the tree is depicting

Question 22

Synapomorphy

Answer 22

A shared derived character that comes from a common ancestor and was inherited by all its descendants

Question 23

Cladistics

Answer 23

Phylogenetic methods that construct trees by grouping taxa into clades according to their shared derived characters

Question 24

Homplasy

Answer 24

Character state similarity not due to shared descent but maybe by convergent evolution or evolutionary reversal

Question 25

Convergent evolution

Answer 25

The independent origin of similar traits in separate lineages

Question 26

Evolutionary reversal

Answer 26

The reversion of a derived character state to its ancestral state

Question 27

Exaptation

Answer 27

A trait that originates performing one function, and which is later co-opted for a new function. Ex) How the synapsid jaw eventually became todays ear bones

Question 28

Background extinction

Answer 28

The normal rate of extinction for a taxon or biota

Question 29

Mass extinction

Answer 29

A statistically significant departure from background extinction rates that results in substantial loss of taxonomic diversity

Question 30

What were the big five mass extinctions?

Answer 30

The Ordovician event, the Devonian event, the Permian event, the Triassic event, and the Cretaceous event

Question 31

Coevolution

Answer 31

Reciprocal evolutionary change between interacting species, driven by natural selection

Question 32

Reciprocal selection

Answer 32

Selection that occurs in two species, due to their interactions with one another. Reciprocal selection is the critical prerequisite of coevolution.

Question 33

Geographic mosaic theory of coevolution

Answer 33

A theory that proposes that the geographic structure of populations is central to the dynamics of coevolution. The direction and intensity of coevolution varies from population to population, and coevolved genes from these populations mix together as a result of gene flow

Question 34

Coevolutionary escalation

Answer 34

Species interact antagonistically in a way that results in each species exerting reciprocal directional selection on the other. As one species evolves to overcome the other, it in turn selects for new weaponry in its opponent.

Question 35

Mullerian mimicry

Answer 35

Occurs when several harmful or distasteful species resemble each other in appearance, facilitating the learned avoidance of predators

Question 36

Batesian Mimicry

Answer 36

Occurs when harmless species resemble harmful or distasteful species, deriving protection from predators in the process

Question 37

Endosymbionts

Answer 37

Mutualistic organisms that live within the body or cells of another organism

Question 38

Retrovirus

Answer 38

An RNA virus that used an enzyme called reverse transcriptase to become part of the host cells’ DNA. HIV is an example