Chapter 27

Question 1

commonalities

Answer 1

• Phylogeny
• branch
• node
• tip
• outgroup

Question 2

Phylogeny

Answer 2

evolutionary history of a group of organisms

Question 3

Branch

Answer 3

population through time

Question 4

Node

Answer 4

fork in the tree

represent a split where the two groups differ for some reason

Question 5

Tip (terminal node)

Answer 5

end of a branch

Question 6

Outgroup

Answer 6

a taxon closely related to a monophyletic group but not a part of it

Question 7

Topologies

Answer 7

branching patterns

Question 8

Trees are organized according to …

Answer 8

evolutionary history

Question 9

Principle of parsimony

Answer 9

Question 10

Phenetic

Answer 10

genetic distance
the computer estimates the differences in data between animals and places them in areas with the closer relatives

Question 11

Cladistics

Answer 11

shared derived characteristics
Ancestral traits: existed in the ancestor
Derived traits: is a modified version of the ancestral trait
Each clade is determined by synapomorphy

Question 12

Homology

Answer 12

traits are similar because of a shared ancestry

Question 13

Convergent evolution or Homoplasy

Answer 13

traits are similar but there is no common ancestry (convergent evolution)

Question 14

Sine genes

Answer 14

short interspersed nuclear evidence

Question 15

Synapmorphy

Answer 15

shared derived trait that is present in the recent ancestor and lacking in the ancestral

Question 16

Fossils

Answer 16

Question 17

After burial

Answer 17

Decomposition doesn’t happen-preservation
Sediments make pressure-flat fossil
Decomposition slowly- Casts
Decomposition very slowly – premineralized fossil

Question 18

Limitatons of studying the fossil record

Answer 18

Area of active deposition
Slow decomposition (ie. hard parts)
Tectonic movement
Natural disasters

Question 19

Three eons

Answer 19

Hadeon, Archeon, Proterozoic

Question 20

Precambrian

Answer 20

Beginning of the universe to 542 MYA
The solar system came into existence
Earth, land, oceans,
photosynthetic cells, eukaryotes,
red algae, lichens, sponges,
ocean oxygenated, first bilateral

Question 21

Three eras

Answer 21

Paleozoic, Mesozoic, Cenozoic

Question 22

Phenerozoic eon

Answer 22

542 MYA-present

Five major extinctions,
This is where oxygen became common
Multicellular organisms occurred

Question 23

Paleozoic

Answer 23

initial diversification of animals

Question 24

Mesozoic

Answer 24

dinosaurs and gymnosperms
Gymnosperms: seeds no flowers
Angiosperms: seeds within ovaries, flowering

Question 25

Cenozoic

Answer 25

Angiosperms and mammals

Question 26

Paleontologist focuses

Answer 26

Extinctions New species and quick diversifications

Question 27

Extinctions

Answer 27

60% of species are dead in 1 million years We are in a possible sixth Five main ones have definitely occurred

Question 28

Background extinction

Answer 28

populations are at zero for normal environmental changes

Question 29

Mass extinctions

Answer 29

sudden, temporary, large events cause animal dieoff

Question 30

End Permian extinction

Answer 30

251 MYA Nearly 60% families died out Considered one of the worst

Question 31

End Permian extinction causes:

Answer 31

* increase in CO2, heat and SO2 leading to global warming and sulfuric acid in atmosphere, * ocean was anoxic, * sea level drop * High CO2 and low O2 lead to low atmosphere places being the only livable areas

Question 32

End Cretateous extinction

Answer 32

65 MYA Caused by a large impact of a asteroid Caused 60-80% of multicellular organism death

Question 33

End Cretateous extinction evidence

Answer 33

Soot and ash Tsunami Sulfuric acid in water and air Fireball of hot gases would make fires

Question 34

Selectivity

Answer 34

Each extinction doesn’t quite kill everything End Cretaceous: dinosaurs pterosaurs, large marine reptiles died Turtles, mammals, crocodiles, and amphibians survived Why? Hibernation, size, food availability

Question 35

Recovery

Answer 35

Diversity from simplification Adaptive radiation Empty niches The genes that survived got to reproduce (limitations of evolution)

Question 36

Adaptive radiations

Answer 36

Single lineage produces multiple descendant species in multiple habitats with multiple resources

Question 37

Adaptive radiations triggered by:

Answer 37

New resources New ways to exploit resources

Question 38

Cambrian explosion

Answer 38

565 MYA-505 MYA every major group of animals appears Before this sponges and bacteria were the main life forms

Question 39

Cambrian explosion Why?

Answer 39

High oxygen levels Predation occurred Predator prey arms race Movement into new niches: ocean floor-ocean-lakes and rivers-coast-land-mountains Mutations increase # Hox genes Hox genes are the genes that control embryotic development