Unit test 2: (Ch. 21-23)

Question 1

What is phylogenetics?

Answer 1

science of classifying organisms according to common ancestry based on characteristics

Question 2

what are the 2 related evolutionary patterns?

Answer 2

1-nested patterns of similarities found among species on present earth
2-historical pattern of evolution recorded by fossils

Question 3

what are observed species descendants of?

Answer 3

modified descendants of earlier ones that had undergone s**peciation events from ancestral species **

Question 4

what does a pattern of nested similarities among species indicate?

Answer 4

descent with modification and accumulation of change (adaptive radiation)

Question 5

what are nested patterns?

Answer 5

similarities or differences in…
1- morphological characteristics
2- molecular characteristics

Question 6

what is a phylogeny?

Answer 6

hypothesis for evolutionary history of species or group of species

Question 7

what does every node in a phylogeny represent?

Answer 7

a common ancestor

Question 8

phylogentic trees and cladograms display the best model for what?

Answer 8

hypotheses of relatedness of organisms

Question 9

when discussing the characters and how phylogentic trees are inferred by the comparison of characters sgared among different groups of organisms, what type of characters are used? (3)

Answer 9

-anatomical
-physiological
-molecular features

Question 10

can character states be similar in phylogenetics?

Answer 10

yes

Question 11

what are the 2 reasons character traits can be the same?

Answer 11

-present in common ancestor of 2 groups and retained over time = homolgous character
-evolved independently in 2 groups as an adaptation similar to environments = analogous character

Question 12

what is an example of a homologous character?

Answer 12

amniotic egg is a characteristic that all sauropsids share because all extent organisms in a tree have that feature

Question 13

what is an example of an analogous character?

Answer 13

wings because the ancestors of birds and bats likely did not have wings (it was evolved)

Question 14

what structures are not useful in building a phylogenetic tree?

Answer 14

-character states in monophyletic group
-character states present in all taxons

Question 15

what do we need to develop hypotheses of evolutionary relationships?

Answer 15

homologies that are shared by some but NOT ALL of the members of the group under consideration

Question 16

what are synapomorphies?

Answer 16

homologies (characters)that are shared by some but not all memebers of the group under consideration

Question 17

where do you find the synapomorphies in the tree?

Answer 17

near the nodes

Question 18

how should you compare different species or figure out how closely related they are?

Answer 18

compare their DNA and compare their sequences

Question 19

what can you build to compare species’ differences?

Answer 19

Data matrix of their differences

Question 20

What is sister taxa?

Answer 20

the 2 or + closest related species

Question 21

what is are molecular clocks?

Answer 21

yardsticks for measuring absolute time of evolutionary change based on observation of genes that evolve at constant rates

Question 22

in molecular clocks, what is proportional to the time elapsed since the species branched from a common ancestor?

Answer 22

point mutations

Question 23

what is an example of how molecular clocks have been useful?

Answer 23

provided insight into evolution of homo sapiens

Question 24

How did early earth produce simple cells? (how did life on earth begin?)

Answer 24

4 main stages:
-abiotic synthesis of small organic molecules
-joining of small molecules into marcomolecules
-packing of these molecules into protocells
-origin of self-reolicating molecules that made inheritance possibkle and natural selection to make improvements

Question 25

what is the Hadean?

Answer 25

first geological eon

Question 26

what is the hypotheses that scientists had made about the synthesis of the monomers?

Answer 26

-early earth's atmosphere was a **reducing environment** which organic molecules could have formed -**energy** for this organic synthesis could have come from **lightning** and **intense UV radiation**

Question 27

what were scientists able to conclude when they tested small organic molecules in a reducing atmosphere?

Answer 27

that amino acids and notrogenous bases could be formed

Question 28

what is a reducing atmosphere?

Answer 28

limited oxygen

Question 29

how did they form organic polymers?

Answer 29

dripping solutions of monomers onto hot sand, clay or rock

Question 30

what is an example of how an organic polymer was made?

Answer 30

nucleotide + hot sand/rock/clay = RNA

Question 31

what are protocells?

Answer 31

**aggregates** of **abiotically**(not living) produced molecules **surrounded** by a **membrane** or membrane-like structure

Question 32

what are the properties of life of protocells?

Answer 32

-ability to divide/reproduce, maintain metabolic reactions, maintain internal environment (homeostasis)

Question 33

what is homeostasis of a cell?

Answer 33

maintain internal evironment

Question 34

what are the self-replicating molecules in early life?

Answer 34

Ribozymes from RNA

Question 35

why is RNA most likely the first genetic material on earth?

Answer 35

because it is -**flexible** by it being ***single*** ***stranded*** and ***folding*** to create different shapes

Question 36

how does natural selection apply to molecules?

Answer 36

**self-replicating **molecules leave behind **offspring** with **v****ariation in heritable traits**. Natural selection **selects** **cells** that are more and more **adapted** to the **environment** (survival of the fittest)

Question 37

what does fossil record tell us about evolution on earth?

Answer 37

shows changes in the kinds of organisms on earth over time

Question 38

what does deeper strata display in fossil records?

Answer 38

**older** organisms and how many **extinct** **organisms** look **similar** to **organisms** alive **today**

Question 39

what makes fossil record incomplete?

Answer 39

many of earth's organisms did **not die in the right place at the right time**

Question 40

how are fossils dated?

Answer 40

radiometric dating= decay of radioactive isotopes

Question 41

how is the rate of decay expressed in radioactive dating?

Answer 41

the half-life of the parent isotope= time required for 50% of the parent isotope to decay

Question 42

is the half-life of isotopes affected by the environmental factors?

Answer 42

no

Question 43

what are common isotopes used in radiometric dating?

Answer 43

carbon-14 and uranium-238

Question 44

what was the earliest life? -Eukaryotic -prokaryotic -archaeic

Answer 44

prokaryotic

Question 45

what are the oldest known fossils that are 3.5 billion years old?

Answer 45

stromatolites

Question 46

what are stromatolites?

Answer 46

**rocklike** structures composed of **layers** of **bacteria** and **sediment**

Question 47

what produced all required compounds for life by using energy in chemicals or light?

Answer 47

autotrophs

Question 48

what is the term used for producing compounds for life by using energy in chemicals?

Answer 48

Chemo**autotrophs**

Question 49

what is the term used for producing compounds for life by using energy in light?

Answer 49

Photoautotrophs

Question 50

where does most of the atmospheric oxygen originate from?

Answer 50

photosynthesis

Question 51

what is oxygen revolution?

Answer 51

large increase in atmospheric O2 (on a graph)

Question 52

what is a powerful greenhouse gas?

Answer 52

methane

Question 53

what would atmospheric O2 have done?

Answer 53

removed green house gas, methane and created a snowball earth because of it

Question 54

how are sponges and mammals both considered animals?

Answer 54

because of the **common characteristics of animals**

Question 55

what are the 6 common characteristics of animals?

Answer 55

-no cell walls -multicellular -mobility (internal & external) -Heterotrophy (needs to eat other organisms or substances) -Embryonic tissues -Collagen (matrix of connective tissues)

Question 56

what did the evolution of multicellularity and differentiation of embryonic tissues give rise to?

Answer 56

new body plans of animals

Question 57

what are the 4 body plan characteristics?

Answer 57

-symmetry -presence of segmentation -cephalization -appendages

Question 58

what type of symmetry is there? (3)

Answer 58

-asymmetric = no symmetry -radially symmetric= circular like cnidarians -bilaterally symmetric= body that divides into 2 halves

Question 59

what is segmentation?

Answer 59

divisions of body into a series of **repetitive** segments

Question 60

what is metamersim?

Answer 60

linear series of body segments which are similar in structure like a **worm**

Question 61

what is cephalization?

Answer 61

from segmentation, it allowed a head region where sensory equipment is concentrated

Question 62

what did cephalization influence in evolution?

Answer 62

nervous system

Question 63

What are taxonomic groups?

Answer 63

nested categories that share **morphological** and **molecular** **characteristics** from **common ancestor**s and evolutionary relationships

Question 64

what is more similar/evolutionary related between family and order?

Answer 64

family because Domain Kingdom Phylum Class Order **Family** Genus Species

Question 65

what does genus mean?

Answer 65

a class, or group that links through common characteristics or 1 common characteristic

Question 66

What do chordates have?

Answer 66

-notochord -forsal, hollow nerve cords -Pharingeal slits -embryonic tail

Question 67

what is a notochord?

Answer 67

structure that provides skeletal support but it doesn't have to be bone

Question 68

what is a dorsal, hollow nerve cord?

Answer 68

a structure that develops into the **brain** and **spinal** **chord**

Question 69

what is a pharingeal slit?

Answer 69

structure present in the **embryo** that develop into **digestive, respiratory or sensory **organ

Question 70

what is an embryonic tail?

Answer 70

extends between the anus

Question 71

what are craniates?

Answer 71

chordates that evolved a **skull**

Question 72

what is a vertebrate?

Answer 72

**craniate** that **evolved** **vertebrae** along **notochord**

Question 73

What is an example of an invertebrate craniate?

Answer 73

hagfish

Question 74

What are jawed vertebrates called?

Answer 74

gnathostomes

Question 75

what is an example of a gnathostome?

Answer 75

sharks, amphibians, birds...

Question 76

what are fully aquatic gnathostomes called?

Answer 76

chondrichthyans (these are sharks)

Question 77

what are osteichthyes?

Answer 77

fish that are **ossified** skeletens (bone) that evolved **lungs**

Question 78

what does the class actinopterygii include?

Answer 78

ray-finned fish distinguished by bony rays

Question 79

what does the class Sarcopterygii include?

Answer 79

lobe-finned fish where their skeleton protrudes in their fins

Question 80

what do Coelacanths include?

Answer 80

lungfish (like an in between water and air)

Question 81

common ancestor to coelacanths?

Answer 81

tetrapods

Question 82

what do tetrapods include?

Answer 82

amphibians, reptiles and mammals

Question 83

reptiles and mammals are sister taxa?

Answer 83

yes they both share the amniotic egg in common

Question 84

what do all mammals share?

Answer 84

hair and produce milk

Question 85

what does the class mammalia include?

Answer 85

-monotremes -marsupials -eutherians (placenta = human)

Question 86

what are monotremes?

Answer 86

egg laying mammals