Ultimate Test 2 Study Guide Flashcards
what kind of information do phylogenies provide?
they show the patterns of evolution and how species are related to each other through ancestry
on what infromation are phylogenies based?
based on data from morphology, DNA and development
Phylogenies are hypotheses based on data. What does that mean?
it means that it uses morphology, DNA and development to estimate evolutionary history
why are traits that are the result of convergent evolution misleading for making phylogenies?
they create the illusion of shared ancestry between distantly related organisms, masking their true evolutionary relationships
Why is it not appropriate to clssify life as either prokaryotes or eukaryotes?
it is an oversimplification because archea are more closely related to eukaryotes than bacteria
what do prokaryotes and archea have in common (3)
no nucleus or membrane-bound organelles, single-celled, reproduce by binary fission
why don’t we use the term prokaryote in classification?
it’s a paraphyletic group, meaning it doesn’t include all descendants of a common ancestor, and doesn’t accurately reflect the evolutionary relationships of Bacteria and Archaea
What do you think might explain the closer relationship between archaea and eukaryotes then between archaea and bacteria? (2)
shared genetic traits in RNA (rRNA) and the metabolic pathways are more similar to eukaryotes than bacteria
What is the relationship between the structure of cell walls in bacteria and their function?
Peptidoglycan, is a mesh-like structure that provides rigidity and strength which helps with holding shape and serving as a target for certain antibiotics
gram-positive bacteria have …
a single membrane
gram negative bacteria have…
double membranes
capsule definition
a sticky outer layer surrouunding the cell walls of many bacteria
capsule function (3)
more efficient adhesion, protection from dehydration, prevent invasion from pathogens
Endospores
dormant structures that help bacteria survive in unfavorable conditions
What is necessary for natural selection to occur in the experimental population in the Cooper and Lenski experiment? (3)
variation in traits, inheritance of those traits, and differential reproductive success (or fitness)
what is the source of variation in the cooper and leneski experiment?
mutations that increased the rate of mutation to cit+
what trait is favored in the cooper and linesky experiment?
the ability to use citrate
What are the sources of genetic diversity in bacteria? (3)
mutation, horizontal gene transfer and the movement of mobile genetic elements
what is the difference between horizontal transfer and vertical transfer of genes?
Vertical gene transfer involves passing genes from parent to offspring, while horizontal gene transfer is the transfer of genetic material between organisms that are not direct descendants
what are 3 implications of horizontal transfer of genes?
the rapid spread of antibiotic resistance, the evolution of new traits, and the emergence of novel species, particularly in prokaryotes
what are the 3 ways that horizontal transfer happens?
transformation (taking up DNA from the environment), conjugation (transferring DNA between cells via direct contact), and transduction (virus-mediated transfer of DNA
What types of resources can prokaryotes use to generate energy? (4)
light (phototrophs) or chemical compounds (chemotrophs), and carbon from carbon dioxide (autotrophs) or organic compounds (heterotrophs)
What features of archaea do you think has contributed to the delayed discovery of archaea? (3)
Morphological Similarity to Bacteria, Extreme Habitat Preference, Resistance to Standard Antibiotics
What are some of the roles that prokaryotes play in a functioning ecosystem? (3)
Decomposers (Nutrient Recycling), nitrogen fixation, and Oxygen Production (Photosynthesis)
Explain how antibiotic resistance can evolve (3)
The development of resistance is accelerated by mutations, horizontal gene transfer, and selection pressures caused by improper or excessive use of antibiotics.
What is the selection pressure (the thing in the environment) that favors resistant forms of bacteria?
the presence of antibiotics in the environment
Why do you think that resistance evolves so rapidly in bacteria? (4)
Bacteria evolve resistance rapidly because they reproduce quickly, mutate frequently, share genes efficiently, and face constant antibiotic pressure
Are protists a clade? How do you know?
No, protists are not a clade because they do not form a monophyletic group—meaning they do not include all the descendants of a single common ancestor. Instead, protists are a paraphyletic group, meaning they include some but not all descendants of a common ancestor.
how are primary endosymbiosis and secondary endosymbiosis are different from each other.
primary endosymbiosis - engulfs a prokaryotic cyanobacteria and produces A simple chloroplast with two membranes
secondary endosymbiosis - engulfs a eukaryotic algae (with a chloroplast) and produces a complex chloroplast with 3-4 membranes
main outcomes of secondary endosymbiosis (4)
complex plastids with extra membranes, the spread of photosynthesis to new groups, gene transfer, and increased biodiversity in marine and terrestrial ecosystems
What is the significance of the number of plastid membranes in eukaryotes
reveals the type of endosymbiosis that occurred
what excavate lineages have non-functional or reduced function in the mitochondria? (3)
diplomonads (Giardia), parabasalids (Trichomonas), and some euglenozoans
How can you explain that some protists have non-functional or
reduced function mitochondria? (2)
adaptation to anaerobic environments and evolutionary gene loss
What is the origin of the plastid in euglenozoans?
secondary endosymbiosis of a green alga
SAR subgroups
stremenopiles, alveloates, rhizaria
What traits do brown alga and plants share and how? (4)
multicellularity, photosynthesis, cellulose-based cell walls, alternation of generations - convergent evolution
How do you know that the similarities between brown alga and plants are caused by convergent evolution?
because they both originate from different types of endosymbiosis
What disease does plasmodium create?
causes malaria by infected mosquitoes
why is Plasmodium a bastard
because there is no vaccine because everything is resistant
what archeaplastida are considered protists?
red algae, green algae, and chorophytes
two major lineages of unikonts
opisthokonts and ameobozoans
What data helps resolve some of issues associated with the Eukaryote polytomy? (2)
genomic and molecular data help resolve relationships, grouping organisms based on shared molecular and structural characteristics rather than just morphology
Is multicellularity the result of homology or convergent evolution? Explain
The general trait of multicellularity is convergent, as it arose multiple times independently due to similar selection pressures
what supergroup and major subgroup of protists does giardia trichomoras part of
excavata, diplomonads
what supergroup and major subgroup of protists does Trypanosoma euglena part of
excavata, euglena specifically kinetoplastids
what supergroup and major subgroup of protists is pfisteria part of
SAR, alveolata, dinoflagellates
what supergroup and major subgroup of protists is plamodium part of
SAR, alveolata, apicomplexa
what supergroup and major subgroup of protists is paramecium part of
SAR, alveolates, ciliates
what supergroup and major subgroup of protists is porphyra part of
arcaeplastida, red algae
what supergroup and major subgroup of protists is Chlamydomonas -ulva part of
archeaplastida, green algae
To which super groups do land plants belong
archeaplastida
what are land plants closest protist relative?
charophyte a green algae
land plants and and protist relatives get plastids by what process?
primary endosymbiosis
secondary endosymbiosis
a process in which a eukaryotic cell engulfs another eukaryotic cell that has already undergone primary endosymbiosis
Benefits of plants colonizing land (4)
access to unfiltered light, access to more atmospheric carbon dioxide, access to minerals in the soil and release fromthe competition, predation, and disease
What are the conditions that plants had to overcome to be able to colonize land? (2)
lack of structural support against gravity and decrease access to water (dessication - drying out)
what adaptation was for more structural support when plants colonized land?
cellulose-rich walls, lignin
what adaptation was to combat dessication when plants colonized land?
cuticle and stomata
Alternation of generations
Plants alternate between the diploid sporophyte and haploid gametophyte, and between asexual and sexual reproduction
why did most land plants adapt to have a dependent embryo?
to increase survival rates due to dessication and less nutrients
why did most land plants adapt to have walled spores?
to protect their reproductive cells from dessication, UV radiation, and mechanical damage
why did most land plants adapt to have multicellular gametophytes? (3)
provide more resources for developing gametes, protect them from environmental stress, and increase reproductive success
Why would it be taxonomically inappropriate to classify plants into vascular and non-vascular
plants?
it does not reflect true evolutionary relationships, it is just a characteristic. modern plant taxonomy groups plants based on monophyletic lineages, providing a more accurate evolutionary framework
what is the main difference between the life cycle of moss and ferns
mosses have a dominant gametophyte phase (n) and ferns have a dominant sporophyte stage (2n)
What is the main difference between megaphyls and microphyls?
microphylls are small with a single, unbranched vein, while megaphylls are larger with a complex, branched vascular system
what are sporophytes and what kind of plants would you find them in?
A sporophyte is the diploid (2n) stage in the life cycle of plants that undergo alternation of generations and they are in all land plants
why would it be taxonomically inappropriate to divide vascular plants into seed and seedless plants
seedless plants are not a monophyletic group
How does the alternation of generations life cycle change from non-vascular plants through
seed plants?
non-vascular plants are gametophyte dominant (n) and seed plants are sporophyte dominant (2n)
What advantages do seed plants gain from the changes to the life cycle? (5)
The gametophyte is protected within the sporophyte’s tissues, can reproduce in dry environments, Seeds allow plants to survive through unfavorable seasons, increases survival rates and enables plants to colonize diverse environments, and larger, more complex structures like trees can outcompete smaller, spore-reliant plants
What are the two types of spores and what do they
produce
Microspores → Produce male gametophytes (pollen grains)
Megaspores → Produce female gametophytes (ovules/egg-producing structures)
Gymnosperms were able to survive after the demise of the lycophyte trees. Why?
gymnosperms were better adapted to drier, harsher conditions, while lycophyte trees were left behind in a world that no longer suited them
What are the three main
groups of gymnosperms? Which one is the most diverse?
cycads, ginkgo, and conifers (most diverse)
