Macroevolution Chapter 5

Question 1

What are some textbook examples of remote corners of the Earth where fossils have been found?

Answer 1

-Gobi Desert in Mongolia
-Rocky Outcrops of Madagascar
-Badlands of South Dakota

Question 2

What is Macroevolution?

Answer 2

large-scale evolutionary processes

Question 3

Classification Definition

Answer 3

A system that helps Biologists organize diversity into categories while simultaneously indicating evolutionary relationships.

Question 4

Animal Ch.5 Textbook definition

Answer 4

Multicellular organisms that move about and invest food

Question 5

Phyla (sing. Phylum)

Answer 5

20+ major groups within the Kingdom of Animalia

Question 6

Chordata

Answer 6

one of the phyla; includes all animals with a nerve chord, gill splits (at some stage of development), and a supporting chord along the back. Most chordates are vertebrates.

Question 7

Vertebrate

Answer 7

Animals with segmented bony spinal columns. Ex: Fishes Amphibians, reptiles (including birds), and mammals.

Question 8

Classification chart (modified by Linnaeus): Animals places in certain categories based on structural similarity. Not all members of categories depicted; 20 orders of placental animals exist, 8 are shown.

Answer 8

Question 9

Taxonomy

Answer 9

Field that specializes in establishing the rules of classification.

Question 10

Traditional vs Modern Classification

Answer 10

Traditional: classified first according to physical similarities
Modern: Must reflect evolutionary descent to be useful.

Question 11

Daeschler and Shubin et al. 2006

Answer 11

Preserved fossils from Canada have provided evidence of how transition from aquatic to land living took place & what earliest land vertebrates looked like.

Question 12

Hox genes

Answer 12

a few regulatory genes that directed forelimb development in all vertebrates.

-Most Invertebrates have 10 Hox genes, fruit flies have 8

-Vertebrates have more; Example: Mammals have 39.
Reason being: Over time invertebrate versions have duplicated in vertebrates.

-Observation: vertebrate Hox genes are descended from invertebrate Hox genes

Question 13

Homologies

Answer 13

structures that are shared by species on the basis of descent from a common ancestor

Question 14

Ex. of Homologies

Answer 14

Similarities in the forelimb bones of these land vertebrates (tetrapods) can be easily explained by descent from a common ancestor.

Question 15

Analogies (Analogous Structures)

Answer 15

Similarities between organisms strictly on common function with no assumed evolutionary descent

Question 16

Homoplasy (homo: same, plasy: growth)

Answer 16

The separate evolutionary development of similar characteristics in different groups of organisms.

example: wings in birds and butterflies

Question 17

Evolutionary Systematics

Answer 17

One of two major approaches (“schools”) biologists use to interpret evolutionary relationships.

Traditional approach to classification (and evolutionary interpretation) in which presumed ancestors and descendants are traced in time by analysis of homologous characters.

Question 18

Cladistics

Answer 18

Second approach used by biologists to interpret evolutionary relationships.

An approach to classification that attempts to make rigorous evolutionary interpretations based solely on analysis of certain types of homologous characters.
(those to be considered derived characters)

Question 19

Fleagle 1999: Primate Evolutionist

Answer 19

“virtually all current studies of primate phylogeny involve the methods and terminology” of cladistics.

Question 20

Similarities: Systematic Classification & Cladistics

Answer 20

-interested in tracing evolutionary relationships and constructing classifications that reflect these relationships

-recognize that organisms must be compared using specific features (called characters); some characters are more informative than others

-focus exclusively on homologies

Question 21

Significant differences: Systematic Classification & Cladistics

Answer 21

-how characters are chosen, which groups are compared, how results are interpreted and eventually incorporated into evolutionary schemes and classifications.

Primary difference: Cladistics more explicitly and rigorously defines kinds of homologies that yield the most useful information.

Cladistics focuses on traits that distinguish particular evolutionary lineages.

Question 22

Ancestral

Answer 22

Characters (traits) inherited by a group of organisms from a remote ancestor and thus not diagnostic of groups (lineage) that diverted after the character first appeared; also called Primitive.

Simple: means that a character seen in two organisms is inherited in both of them from a distant ancestor

In most cases, ancestral characters doesn’t supply enough info to make accurate evolutionary interpretations of relationships between different groups.

Question 23

Simplified Ancestral (Primitive) Definition and Explanation

Answer 23

Traits or features that were present in very early ancestors.
This does not mean “bad” or “less evolved,” it just means OLDERS traits that have been passed down without much change

Example: Having five fingers is an ancestral trait for humans and many other mammals- a trait passed by onto us by our ancient ancestors

Question 24

Clade
( Cladistics Focus)

Answer 24

A group of organisms sharing a common ancestor. The group includes the common ancestor and all descendants.

Question 25

Simplified Clade definition and explanation

Answer 25

Clade: Basically a group of organisms that includes a *common ancestors* and *all its descendants* Example: A whole branch of a family tree: one parent and all the grandchildren, great-grandchildren etc. *Important: Everyone in the clade shares something because they all come from the same ancestor

Question 26

Monophyletic

Answer 26

Referring to an evolutionary group (clade) composed of descendants sharing a common ancestor.

Question 27

Simplified Monophyletic Definition and Example

Answer 27

A Monophyletic group is a group that includes *one common ancestor* and all the species that came from it. *No one is left out* Ex. Humans, Chimpanzees, and gorillas all come from one single ancestor. Grouping all of them together (including that ancestor) you have a monophyletic group.

Question 28

Polyphyletic

Answer 28

Referring to an evolutionary group composed of descendants with more than one common ancestor (and thus not a true clade)

Question 29

Polyphyletic Simplified

Answer 29

A group that does *NOT* share a recent common ancestor; it is a mix of species from different ancestors. *It's like grouping together unrelated things just because they look similar* Ex. Grouping bats (mammals) and birds (not mammals) just because they both have wings. That is polyphyletic. They didn't get wings from the same ancestor; they evolved wings separately

Question 30

Derived (Modified) * Character of interest in identifying a clade

Answer 30

Referring to characters that are modified from the ancestral condition and thus diagnostics of particular evolutionary lineages.

Question 31

Derived (Modified) Simplified

Answer 31

A derived trait is new trait that evolved later- it is different from what their ancestors had. It is a "recent change" compared to the older, ancestral traits

Question 32

A CLOSER LOOK: Evo-Devo: The Evolution Revolution

Answer 32

- 1999: evolutionary developmental biology field, or eve-devo, emerged. -Main goals of evo-devo: discover how animals are put together and how genes that control their development can, over time, produce new species.

Question 33

Answer 33

Anthropods (invertebrates with jointed feet, including all insects, spiders, and crustaceans) have segmented bodies and legs; and many have segmented wings, which ultimately derived from leg-like appendages

Question 34

Anatomical similarities of the millions of species on Earth (including incests and marine life)

Answer 34

-Bilateral Symmetry -Modular body plans of repeated segments

Question 35

Answer 35

Vertebrates also have segmented body parts, and this segmentation begins with the development of head and the vertebral column. Although number of vertebrae and number of each type of vertebra vary among species, the spine is made up of repeated segments.

Question 36

Mouse Genome Sequencing Consortium, 2002

Answer 36

Around 99% of mouse genes have a human counterpart -Roughly 10% of our genomes that consist of regulatory genes has almost exactly the same DNA sequence as the regulatory genes of mice

Question 37

Real answer to how Macroevolution occurs?

Answer 37

changes in regulatory genes 25 years ago, changes in protein coding genes were believed to be the answer

Question 38

DNA Sequencing of Regulatory Genes

Answer 38

The sequences don't differ greatly among species; however (THIS IS KEY), these genes do differ when it comes to when, where, and how long they function. -Lead to major physical differences because anatomical development depends on genes turning on and off at different times at different places.

Question 39

Genetic Took Kit

Answer 39

Group of body building regulatory genes that biologists refer to. -highly conserved and shared by all vertebrates and invertebrates -through roughy 600 million yrs of evolution, many genes that make up GTK have somewhat changed by mutation & duplicated to produce families of genes -Composed of genes that make two basic kinds of proteins: Transcription Factors and Signaling Molecules

Question 40

Transcription Factors

Answer 40

Protein Molecules that bind specific DNA segments called 'Enhancers' or 'Promoters' -By binding enhancers, TF switch genes on and off; also determine how long genes produce protein -Many produced by Homeobox Genes; contain a highly conserved region of 180 nucleotides called the 'Homeobox'; this sequence codes for the proteins that bind to enhancers: Hox contains homeoboxes

Question 41

Hox Gene Study (Lutz et. al. 1996)

Answer 41

Showcases how conserved and interchangeable hot genes are between species; Fruit flies can function normally with Hox proteins derived from chick embryos -Indicates genes haven't changed much since fruit flies and chickens last shared a common ancestor some 600 million years ago

Question 42

Quote from Charles Darwin's last paragraph in Origin of Species

Answer 42

"There is grandeur in this view of life... from so simple a beginning endless forms most beautiful and most wonderful have been, and are being evolved."

Question 43

Answer 43

Simplified example that helps clarify basic principles used in cladistic anyalsis. -Hypothetical lineage: First major division (I) differentiates passenger cars from trucks (frame, suspension, wheel size, open cargo) (II) Diversification is between luxury cars and sports cars (engine size & type, wheel base size, decorative racing type) A. Usage: Presented with unknown vehicle, how do you decide the type of vehicle? Ancestral: four wheels, a steering wheel, and a driver's seat. No cargo bed, but has a racing stripe, you can conclude its a car, a sports car, since it has a derived feature presumable of ONLY one group B. If presented with an SUV with a racing stripe? Careful Analysis: SUVs are basically trucks; the presence of a racing stripe can be seen as a 'Homoplasy' with sports cars. What is 'ancestral' and what is 'derived'? Recognize the complexity (and confusion) of an introduced Homoplasy. Any species can posses only those those characters that have been inherited from its ancestor or that have been subsequently modified (derived) from those shared with the ancestor. So any modification in ANY species is constrained by that species evolutionary legacy- that is, what the species starts out with.

Question 44

FIG. 5-4a Using Cladistics to Interpret Organism

Answer 44

Fascinating question: relationship between dinosaurs and birds -1861, two years after Darwin's Origin of Species, primitive bird was discovered. -Orignal consensus of scientists: no close relationship between this bird to dinosaurs -Discoveries made in the last three decades: Supports close relatedness of birds and some dinosaurs. 1990s China & Madagascar, and elsewhere & the application of the cladistic methods for interpretation of these and other fossils Madagascar: chicken sized, primitive birds dated to 70-65 mya show an elongated toe (similar to a velociraptor) and other similarities to it's close cousins, together compromise a group of small-to medium-sized-ground-living-carnivorous dinosaurs called theropods. China: traces of feathers found embossed in fossilized sediments. Birds are not only descended from dinosaurs, they ARE dinosaurs (and reptiles) Humans are mammals even though being as different from other mammals as birds are from other reptiles. Doubters concerned that feathers might be homoplasy; In the case of theropods and birds, presence of feathers is an excellent example of a 'shared derived' characteristic, which therefore DOES link the lineage. Cladistic Analysis: Several other characteristics,

Question 45

Theropods

Answer 45

Small-to-medium-sized ground-living dinosaurs, dated to approximately 150 mya and thought to be related to birds

Question 46

Shared Derived

Answer 46

Relating to specific character traits shared in common between two-life forms and considered the most useful for making evolutionary interpretations.

Question 47

Figure 5.5

Answer 47

Cladogram: relationship of birds, dinosaurs, and other terrestrial vertebrate. No time on the scale, both living and fossil forms are shown along the same dimension: that is ancestor- descendant relationships aren't indicated.

Question 48

Phylogenetic Tree

Answer 48

A chart showing evolutionary relationships as determined by evolutionary systematics. It contains a time component and implies ancestor-descendant relationships. Traditional evolutionary systematics illustrates the hypothesized evolutionary using a 'Phylogeny', more popularly called: Phylogenetic Tree

Question 49

Cladogram

Answer 49

Strict cladistic analysis shows relationship in a cladogram. A chart showing evolutionary relationships as determined by cladistic analysis. It's based soley on interpretation of shared derived characters. It contains no time component and does not imply ancestor-descendant relationship.

Question 50

Biological Species Concept (Mayr, 1970)

Answer 50

A depiction of species as a group of individuals capable of fertile interbreeding but reproductively isolate from other groups. Preferred by most zoologists

Question 51

Speciation

Answer 51

-The most fundamental of macroevolutionary process -The process by which a new species evolves from an earlier species

Question 52

According to Biological Species Concept:

Answer 52

-New species first producing involves some form of isolation. Ex. Single species, Baboons, composed of several populations distributed over a wide geographical area. Gene exchange between populations (gene flow) will be limited if a geographical barrier, ocean for ex., effectively separates these populations. This is *Geographical Isolation* If baboon population *A is separated from another baboon population *B, members of *A will not be able to mate& reproduce with *B. As time passes (hundreds to thousands of generations), genetic differences will accumulate in both populations. If population size is small, we can assume genetic drift will cause change in allele frequencies in both populations. Consequently the two populations will begin to diverge genetically. If gene exchange is limited, populations can only become more genetically different over time. Further difference can be expected if the baboon groups are occupying slightly different habitats. These genetic differences would occur because of natural selection. Some members can be reproductively fit in their own environment but might show less reproductive success in another groups environment. Allele frequencies will change further resulting in greater divergence.

Question 53

Behavioral Isolation

Answer 53

Resulting from the cumulative effects of genetic drift and natural selection over generations- if two populations of what was once One Species

Question 54

Recognition Species Concept

Answer 54

A depiction of species in which they key aspect is the ability of individuals to identify members of their own species for the purposes of mating (and to avoid mating with members of other species). In theory this types of selective mating is a component of a species concept emphasizing mating and is therefore compatible with the biological species concept .

Question 55

Ecological species concept

Answer 55

The concept that a species is a group dog organisms exploiting a single niche. This view emphasizes the role of natural selection in separating species from one another

Question 56

Ecological Niche

Answer 56

The position if a species within its physical and biological environments. A species ecological niche is defined by such components as diet, terrain, vegetation, type of predators, relationships with other species, and activity patterns, and each niche is unique to a given species. Together ecological niches make up the ecosystem.

Question 57

Interpreting Species and Other Groups in the Fossil Record

Answer 57

Taxonomic Terms for Fossil Primates/ Genus Names: Proconsul, Sivapithecus., Australopithecus, and Homo. -As a result of recombination, each individual organism is unique combination of genetic material, and this uniqueness is often reflected to some extent in the phenotype.

Question 58

Sexual Dimorphism

Answer 58

Differences in physical characteristics between males and females of the same species. For example, humans are slightly sexually dimorphic for bode size, with males being taller on average, than females of the same population. Sexual dimorphism is very pronounced in many species.

Question 59

Species

Answer 59

A group of interbreeding or potentially interbreeding organisms that is reproductively isolated from such other groups.

Question 60

Intraspecific

Answer 60

Within species; refers to variation seen within the same species

Question 61

Interspecific

Answer 61

Between species; refer to variation beyond that seen within the same species to include additional aspects seen between two different species

Question 62

Paleospecies

Answer 62

Species defined from fossil evidence, often covering a long time span.

Question 63

Splitters & Lumpers

Answer 63

Splitters: Researchers that claim speciation occurred frequently during hominin evolution, they often identify numerous fossil hominin species in a sample being studied . Lumpers: Researchers that assume speciation was less common and see much variation as being intraspecific; Lump groups together so that fewer hominin species are identified , named, and eventually plugged into evolutionary schemes.

Question 64

Sensu Lato & Sensu Stricto

Answer 64

Lato: (In the broadest sense) Term scientists refer to a collection of fossils *lumped into a group Stricto: (in the strictest sense) Referred to a collection of fossils that have been split into more specific groups. *This is especially apparent with fossils within the genus *HOMO

Question 65

Genus (pl., genera)

Answer 65

A group of closely related species Presents a challenge to biologists: Grouping species into genera can be quite subjective and is often much debated by biologist.

Question 66

Taphonomy

Answer 66

"Taphos"- The study of bones and other materials come to be buried in the Earth and preserved as fossils *Whether a dead animal is fossilized and how much of it is preserved is dependent partly on HOW it dies, but even more on WHERE it dies . -Likelihood of a dead organism surviving to become a fossil is quite low -Topics Taphonomists try to understand: Process of sedimentation and burial, and the role of carnivores in scavenging animal carcasses

Question 67

Geological Time Scale

Answer 67

The organization of Earth history into eras, periods, and epochs; commonly used by geologists and paleoanthropologists

Question 68

Time Span Encompassing Vertebrate Evolution

Answer 68

Three Eras: Paleozoic, Mesozoic, and Cenozoic

Question 69

Earliest Vertebrate Fossil Record

Answer 69

Paleozoic 500 mya, origins probably much older; Vertebrate capacity to form bone that accounts for their complete fossil record AFTER 500 mya

Question 70

Paleozoic 500 mya - 250 mya -Cambrian 570 -Ordovician 500 -Silurian 430 -Devonian 395 Carboniferous 345 -Permian 280

Answer 70

Several varieties of fishes (including ancestors of modern sharks and bony fishes, four limbed organisms (amphibians and reptiles) appears on Earth. -Profoundly influenced by geographical events (Applies to Mesozoic as well)

Question 71

Continental Drift

Answer 71

The movement of continents on sliding plates of the Earth's surface. As a result, the positions of large landmasses have shifted drastically during the Earth's history Massive Geological Movements: volcanic activity all around the Pacific Rim, mountain building in the Himalayas, and earthquakes.

Question 72

Pangea

Answer 72

Continents came together to form a single colossal landmass. (*in reality, the continents had been drifting on plates, coming together and separating, long before the late Paleozoic around 225mya)

Question 73

Gondwanaland

Answer 73

Early Mesozoic, the southern continents (South America, Africa, Antartica, Australia, and India) Began to split off from Pangea forming a large souther continent

Question 74

Laurasia

Answer 74

Similarly to Gondwanaland, the northern continents (North America, Greenland, Europe, and Asia) consolidated together into this landmass

Question 75

Mesozoic Continental Drift Movement

Answer 75

During the late Mesozoic (about 65mya) the continents were beginning to assume their their approximate current positions

Question 76

Effects of Mesozoic Continental Drift

Answer 76

-Profound ramifications -Groups of animals became effectively isolated by the oceans - Significantly influencing the distribution of mammals and other land vertebrates *Continued into the Cenozoic and still occurring but not as drastic

Question 77

Mesozoic

Answer 77

-Reptile dominant land vertebrates; exhibited a broad expansion into a variety of geological niches (ex. aerial and marine habitats)

Question 78

*A closer look Deep Time

Answer 78

-Fundamental notion termed "Deep Time" By *John Mcfee - Not really understood nor believed -Reach Into Earth's past 1.5 Billion years to approach the earliest documented life *Stephen Jay Gould; The discovery in the late 19th century ," geology's greatest contribution to human thought" *James Hutton; a founder of modern geology and one discoverer of deep time: "Without a vestige of a beginning or prospect of an end" *Carl Sagan; astronomer devised a "cosmic calendar" in his book *The Dragons of Eden (1977)

Question 79

Dinosaur Paleontology

Answer 79

- Warm Blooded - Some varieties were social and probably engaged in parental care Many forms became extinct due to climate changes caused by comets or asteroids - Not all dinos became entirely extinct and their descendants are modern birds

Question 80

Cenozoic

Answer 80

-Divided into two periods, Tertiary(63mil. in duration) and Quaternary (from about 2.6 mya up to and including the present)

Question 81

Epochs

Answer 81

Categories of the geological time scale; subdivisions of periods. In the Cenozoic era, epochs include the *Paleocene, *Eocene, *Oligocene, *Miocene, *Pleistocene, and the *Holocene (referred to as the recent epoch

Question 82

The Age of Mammals "AoM"

Answer 82

- 5400 species of mammals -Cenozoic is referred to as "AoM" - Mammals, along with birds, replaced earlier reptiles as dominant land living vertebrates

Question 83

Account for rapid success of mammals during late Mesozoic and early Cenozoic

Answer 83

-Mammals: Larger brains than typically found on reptile *Cerebrum became generally enlarged- especially the other covering *the NEOCORTEX

Question 84

Neocortex

Answer 84

More recently evolved portions of the cortex that are involved with higher mental functions and composed of areas that integrate incoming information from different sensory organs

Question 85

In utero

Answer 85

- Internal fertilization and Internal development ; not unique to mammals but latter was major innovation among terrestrial vertebrates -Most fishes and reptiles (birds included) lay eggs, development and birth happens externally Mammals (few exceptions) give birth live

Question 86

Placental Mammals

Answer 86

A subclass of mammal. During the Cenozoic, placentals became the most widespread and numerous mammals, today are represented by upward of 20 orders, including primates

Question 87

Heterodont Detention

Answer 87

Having different kinds of teeth; characteristic of mammals, whose teeth consist of incisors, canines, premolars, and molars Ancestral Mammalian dental: three incisors, one canine, four premolars and three molars in each quarter of the mouth in: cutting cani: grasping premo &mo: crushing and grinding * Vast majority of of available fossil data for most vertebrates, consists of teeth

Question 88

Endothermic *endo= within/ internal and thermic = heat

Answer 88

Able to maintain internal body temperature by producing energy through metabolic processes within cells; characteristic of mammals, birds and perhaps some dinos *distinguishes contemporary mammals from reptiles *warm bloodedness *birds being an exception from reptiles

Question 89

3 major subgroups of living mammals

Answer 89

egg laying (monotremes) ex. platypus pouched mammals (marsupials) placental mammals

Question 90

Macroevolution

Answer 90

-Operate on whole species rather than individuals or populations ; take much longer than microevolution to have noticeable impact

Question 91

Adaptive Radiation

Answer 91

The relatively rapid expansion and diversification of life forms into new ecological niches *species or (group of) will diverge into as many variations as two factors allow. 1. adaptive potential 2. adaptive opportunities

Question 92

Generalized and Specialized Characters

Answer 92

closely related to adapt-radi. transition from generalized to specialized characteristics general: trait adapted w/ many functions special: narrow set of functions''

Question 93

Micro and Macro evolution working together

Answer 93

all lineages ; pace speeds up and slows down due to factors that influence the size and relative isolation of populations macro and micro needn't be considered separately