BSCI160: Unit 3

t/f: traits used in making phlyogenies are known as homoplasies

false; homoplasies are not the same as homologous traits. they are analogous traits, traits that have arisen by convergent evolution independently in unrelated groups.

t/f: the wings of birds and bats is an example of convergent traits.

true

label the cladogram using the following terms: internal nodes, terminal nodes, branches

A = internal nodes
B = terminal nodes
C = branches which are usually indicative of lineages

internal nodes

usually represent extinct/ancestral species

terminal nodes

living/extant species

t/f: a clade is a grouping the includes a common ancestor and all its living descendants.

false; a clade includes both living *and extinct* descendants

t/f: clades are constructed based on shared derived characteristics, also known as homologous traits

true; also known as synapomorphies

of the cladograms shown below, which one shows a different evolutionary history from the others?

3

identify the different groupings indicated by numbers 1-3, as either mono, poly, or paraphyletic

1) paraphyletic, 2) polyphyletic, 3) monophyletic

based on this tree, the a group of ponerinae and amblyopninae would be considered
___________; while the myrmicinae and formicinae are ______________________.

a) polyphyletic; monophyletic
b) monophyletic; paraphyletic
c) polyphyletic; paraphyletic
d) Monophyletic; polyphyletic

a) polyphyletic; monophyletic

the position of which pair of taxa could be reversed w/o changing the meaning of the tree?

a) crocs and lizards
b) salamanders and lizards
c) crocs and pigeons
d) mouse and pigeons

c) crocs + pigeons

t/f: one difference btwn a cladogram + a phylogenetic tree is that branch lengths tell evolutionary distance, and this is not the case in cladograms.

true

t/f: the tree of maximum parsiomny is the tree w/ the fewest evolutionary changes

true

which tree is the tree of maximum parsimony?

B

snail shells coil either to the right (dextral) or to the left (sinistral). this left-or-right-handedness of a snail shell is referred to as its chirality. snails of opposite chirality are either unable to mate or they do so w/ significant difficulty. what type of reproductive isolation is this?

mechanical (lock + key) isolation

coral reefs are arguably the most diverse ecosystems on earth. and many coral reef species do broadcast spawning: they release their gametes into the water medium, w/o courtship. which of these reproductive isolation mechanisms might operate for different broad spawning species living on the same coral reef?

gametic isolation

a mule is a hybrid of a male donkey and a female horse. a donkey and a horse are two species able to interbreed but produce sterile offspring. their species integrity is maintained by:

reduced hybrid fertility/hybrid infertility

t/f: in 1960, a homeowner in biglervile, pennsylvania, decided to rear chickens to start an egg selling business. therefore, they built a barn right in the middle of the range of a large population of centipedes who had called that property home even before the "owners" purchased the property. over time, this resulted in the divergence of the once single population into two different centipede species. this is an example of allopolyploidy speciation.

true

speciation that occurs in populations that live in the same geographic area is known as:

sympatric speciation

which sequence represents the most likely chronological order of events in the development of geographic speciation from earliest to latest?

A) formation of a geographic barrier, development of reproductive isolation, genetic
divergence
B) formation of a geographic barrier, genetic divergence, development of reproductive
isolation
C) genetic divergence, development of reproductive isolation, formation of a geographic
barrier
D) genetic divergence, formation of a geographic barrier, development of reproductive
isolation

B) formation of a geographic barrier, genetic divergence, development of reproductive
isolation

which circumstance is most likely to lead to speciation in only a couple of generations?

A) reinforcement
B) polyploidy
C) gametic fusion
D) new environmental pressures
E) allopatric speciation

B) polyploidy

which graph indicated punctuated equilibrium?

2

which best described punctuated equilibrium?

A) speciation occurs due to natural selection
B) speciation occurs due to isolation
C) speciation occurs slowly in geologic time, followed by long periods with very fast
evolutionary change.
D) speciation occurs suddenly and rapidly in geologic time, followed by long periods
with little evolutionary change.

D) speciation occurs suddenly and rapidly in geologic time, followed by long periods
with little evolutionary change.

the group 'prokaryote' is a _________________; and the key distinguishing feature between the
two prokaryote domains is the absence or presence of ______________ in their cell walls.

A) polyphyletic group; peptidoglycan
B) paraphyletic group; capsule
C) paraphyletic group; peptidoglycan
D) monophyletic group; peptidoglycan
E) monophyletic; capsule

C) paraphyletic group; peptidoglycan

what is the evolutionary sequence of metabolic pathways (which came first)?

A) prokaryote photosynthesis, bacterial glycolysis, aerobic respiration
B) prokaryote photosynthesis, aerobic respiration, bacterial glycolysis
C) prokaryote photosynthesis, aerobic respiration, bacterial glycolysis
D) bacterial glycolysis, prokaryote photosynthesis, aerobic respiration

D) bacterial glycolysis, prokaryote photosynthesis, aerobic respiration

____________ & _________________ are eukaryotic organelles that definitely arose from
endosymbiosis.

A) rough ER & smooth ER
B) mitochondria & flagellum
C) chloroplast & mitochondria
D) chloroplast and golgi apparatus

C) chloroplast & mitochondria

all of the following are evidence of endosymbiosis EXCEPT

A) mitochondria and chloroplast ribosomes are similar to bacterial ribosomes
B) mitochondria and chloroplast are similar in size to bacteria
C) mitochondria and chloroplast have double membranes
D) mitochondria and chloroplast have a nucleus

D) mitochondria and chloroplast have a nucleus

per the endosymbiosis theory, mitochondria evolved first before chloroplasts. why? (check all
that apply)

A) all eukaryotes have mitochondria, but only plants and algae have chloroplasts as well
as mitochondria. this suggests, that the first eukaryotic cells first acquired
mitochondria and chloroplasts came later.
B) we actually do not know which one came first - this happened too long ago for us to
know about.
C) all mitochondria form a monophyletic group.
D) during the great oxygenation of the earth, the ability for aerobic metabolism was
critical for survival than was ability to make more sugars.

A) all eukaryotes have mitochondria, but only plants and algae have chloroplasts as well
as mitochondria. this suggests, that the first eukaryotic cells first acquired
mitochondria and chloroplasts came later.

D) during the great oxygenation of the earth, the ability for aerobic metabolism was
critical for survival than was ability to make more sugars.

the term "protists" collectively refers to:

A) all eukaryotes except animals, plants and fungi
B) all eukaryotes except colonial and multicellular groups
C) all unicellular organisms
D) all eukaryotes and some prokaryotes

A) all eukaryotes except animals, plants and fungi

which of the following structures is produced by mitosis in the life cycle of plants?

A) spores
B) zygote
C) seed
D) gametophyte

gametophyte

all sporophytes are:

A) haploid
B) diploid
C) seed-bearing
D) flower-bearing

B) diploid

in the evolution of land plants, which trait evolved first?

a) seeds
b) fruits
c) flowers
d) cuticle
e) vascular tissue

d) cuticle

t/f: all animals are known as eumetazoans

false; all animals are known as metazoans. the eumetazoans ('true' metazoans) are those w/ true tissue layers.

________ do not have any symmetry and are among the most primitive of animal lineages.

a) cnidaria
b) porifera
c) echinodermata
d) nematoda

b) porifera

__________ is a key characteristic of a cockroach; while __________ is a key characteristic of a
jelly fish

a) ecdysis; radial symmetry
b) mammary glands; radial symmetry
c) exoskeleton; bilateral symmetry
d) segmented body; bilateral symmetry

a) ecdysis; radial symmetry

which of the following statements about sponges is NOT true?

a) sponges are among the oldest species on earth.
b) sponges have a porous texture.
c) sponges can produce sexually and asexually.
d) sponges are a class of aquatic invertebrates that includes coral.

d) sponges are a class of aquatic invertebrates that includes coral.

in which of the following the notochord is present in embryonic stage?

a) vertebrates
b) urochrodata
c) some chordates
d) all chordates
e) non-chordates

d) all chordates

which of the following statements is true?

a) all chordates are vertebrates
b) all vertebrates are chordates
c) non-chordates have a vertebral column
d) invertebrates possess a tubular nerve cord

b) all vertebrates are chordates

t/f: all tetrapods lay amniotic eggs

false; amphibians are tetrapods but are not amniotes. no shelled eggs in amphibians and they still rely on water for reproduction

t/f: birds are the most primitive of all amniotes

false; amniotes came from a reptile-like ancestor, and present-day true reptiles have retained some primitive features of that ancestor

________ is a derived trait of hominins

a) cephalization
b) rituals
c) bipedal locomotion
d) use of tools
e) large brain

c) bipedal locomotion

populations of a hominid named _______ arose in africa about 1.6 million years ago and
spread to asia and beyond, becoming the first hominid to leave africa.

a) Homo erectus
b) Paranthropus robustus
c) Homo neanderthalensis
d) Australopithecus africanus
e) Homo habilis

a) Homo erectus

the first known member of the genus Homo was the:

a) Homo sapien
b) Homo erectus
c) Neanderthal
d) Homo habilis
e) Homo ergaster

d) Homo habilis

homologous traits

a trait inherited directly from a common ancestor

analogous traits

trait that is similar between two unrelated species that independently evolved more than once

which trait do we rely on to construct cladograms?

homologous

monophyletic group

includes a common ancestor and all of its descendants joined by a synapomorphy

paraphyletic group

includes a common ancestor but does not include all of the descendants

example of paraphyletic group

fish

polyphyletic group

includes taxa that do not share a *recent* common ancestor, not a useful phylogenetic classification

examples of polyphyletic group

herpetology, marine mammals

label the following on the tree below

A -- node
B -- taxon
C -- extinct
D -- extant
E -- derived trait
F -- ancestral trait

identify the following groupings

yellow -- monophyletic
blue -- paraphyletic
red -- polyphyletic

what are two ways scientists distinguish between homologous and analogous traits when making cladograms?

1) looking at the fossil record of common ancestors
2) extent of morphological similarity

biological species concept

organisms that can breed and produce viable fertile offspring are of the same species

what are some limitations of the BSC?

difficult to apply (potential to interbreed), not applicable to asexual organisms or fossils

habitat isolation

different species live in different regions that impede on their ability to mate

habitat isolation example

rhagoletis race

temporal isolation

different species are able to mate at different times

temporal isolation example

breeding times in frogs

behavioral isolation

different species behave in manners that will be unappealing to their potential mates

behavioral isolation example

bird courtship

mechanical isolation

lock and key -- the reproductive parts do not match

mechanical isolation example

flower anatomy

gametic isolation

gametes fail to recognize each other due to receptors

gametic isolation examples

egg and sperm can't fertilize

reduced hybrid viability

hybrid offspring do not survive

reduced hybrid viability example

sticklebacks

hybrid infertility

sterile offspring

hybrid infertility example

mules

hybrid breakdown

first generation is fine, second generation is weak

hybrid breakdown example

wheat

how would you define the difference between pre- and post-zygotic barriers?

pre-zygotic barriers work to prevent the formation of a gamete, while post-zygotic barriers work to prevent the development of fertile offspring

allopatric speciation

geographical barrier divides species

what are the types of allopatric speciation?

adaptive radiation, mountain ranges/rivers, ring speciation

adaptive radiation

extrinsic ecological opportunities open as new islands form, and allow for organisms to diversify to take up new niches

where can adaptive radiation take place?

islands

mountain ranges/rivers (allopatric speciation)

mountains/waterways develop, habitats that were once uniform become fragmented. populations that end up in these fragmented zones eventually can no longer mingle.

ring speciation

as populations travel around a barrier, small sections of the population stay behind along the way

where can ring speciation take place?

around a lake

example of ring speciation

lizards from lecture

sympatric speciation

species separate without a geographical barrier

what are the types of sympatric speciation?

polyploidy, habitat isolation

allopolyploidy

different species breed to form a hybrid that has a different chromosome number than either parent

autopolyploidy

individual/strain whose chromosome complement consists of *more than two* complete copies of the genome of a single ancestral species

examples of autopolyploidy

plants -- facilitated by ability to self-fertilize

habitat isolation

two subpopulations develop a preference for a specific element of the habitat they share

example of habitat isolation

apple + hawthorne maggot flies

what two scenarios could happen when species originally separated via allopatric speciation come back together?

1) they will breed together making a hybrid, and that hybrid will outcompete either parent (hybrid vigor) + the species will unify once more (fusion)

2) hybrids will not be very fit + both parent species will outcompete --> reinforcement of species distinction

fusion

large areas of hybridization + highly fit hybrids may fuse the two species back into one; leads to hybrid vigor

hybrid vigor

hybrids have a higher fitness than parents

contrast gradualism and punctuated equilibrium

gradualism (anagenesis) is the process of slow, gradual changes over time. punctuated equilibrium (cladogenesis) is the combination of stasis interspersed w/ periods of rapid change.

t/f: gradualism explains the absence of many adaptations from the fossil record

true; the distinction among fossil species is arbitrary with gradualism, appealing to the sketchiness of the fossil record

what causes rapid diversification?

environmental change, (extrinsic/intrinsic) ecological opportunity

environmental change

changes in the environment that allow for new characteristics

environmental change examples

O2 levels, cambrian explosion

extrinsic ecological opportunity

adaptive radiation: new niches open up (due to the removal of old organisms/new areas opening up)

extrinsic ecological opportunity example

mammal diversification after dinosaur extinction

intrinsic ecological opportunity example

exaptation: a characteristic already a part of an organism is tinkered into having a new purpose

intrinsic ecological opportunity example

wings on insects were likely once heat-regulating structures