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bio exam two Flashcards

1
Q

what is a species?

A

a group of organisms that can reproduce with one another in nature and produce fertile offspring

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2
Q

morphological species concept

A

concept that characterizes a species based on its structural features, different species are morphologically indistinguishable in some cases though separation based on lineage is clear

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3
Q

what do all species concepts share? what is a drawback of this?

A

share: under all species concepts, a species is a separately evolving metapopulation lineage
drawback: it is exclusively defined in terms of sexual reproduction

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4
Q

What is the result of speciation?

A

an ancestral species splits into two or more descendant species that are genetically different from one another and can no longer interbreed

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5
Q

In DM model, what happens in each lineage?

A

a new allele arises and becomes fixed at one point; in the other now diverged lineage, a different allele arises at a different point on the gene

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5
Q

Dobzhansky-Muller Model

A

predicts that hybrid incompatibility will be due to interactions between at least two genes (one from each species)

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6
Q

allopatric speciation

A

mode of speciation that occurs when biological populations become geographically isolated from each other and gene flow is prevented/interfered with

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7
Q

what is sympatric speciation?

A

evolution of a new species from a surviving ancestral species while both continue to inhabit the same geographic region

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7
Q

what is a ring species?

A

situation in which two populations which do not interbreed are living in the same region and connected by a geographic ring of populations that can interbreed

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8
Q

What is autopolyploidy?

A

occurs when organisms have more than two sets of chromosomes from the same species

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9
Q

What is polyploidy?

A

condition where the cells of an organism have more than one pair of chromosomes

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10
Q

What are the post-zygotic isolating mechanisms? name examples

A

any factor that reduces/prevents interbreeding between genetically divergent populations or species, but functioning after fertilization has occurred
EX: hybrid inviability, hybrid sterility, and hybrid breakdown

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11
Q

What is allopolyploidy?

A

when organisms contain two or more sets of chromosomes that are from different species

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12
Q

What are the pre-zygotic isolating mechanisms? name examples

A

the separation of different species to keep them from creating offspring by preventing the gametes from forming a zygote
EX: spatial isolation, temporal isolation, mechanical isolation, gametic isolation, behavioral isolation

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13
Q

What is a hybrid zone?

A

areas where genetically distinct populations meet, mate, and leave offspring of mixed ancestry

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14
Q

What is hybridization?

A

process in which two divergent lineages with independent evolutionary histories come into contact and interbreed to produce offspring with a combination of traits from both parents

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15
Q

How is hybridization selected?

A

selection based on phenotypic traits of the hybrid

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15
Q

How does hybridization affect fitness?

A

can reduce fitness by either introducing alleles to a population that are not suited to the local environment or disrupting co-adapted gene complexes

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16
Q

What factors influence whether a lineage will diverge? name factors & examples

A

-genetic factors
-ecological factors
-geographic factors
-reproductive factors
-selection pressures
-genetic drift
-gene flow

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17
Q

What happens during diet speciation?

A

populations diverge and eventually become reproductively isolated due to differences in their ecological niches and dietary preferences

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18
Q

name processes that may occur during diet speciation

A

ecological divergence, trait evolution, reproductive isolation,
gene flow reduction, speciation

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19
Q

What does a pollinator do?

A

helps carry pollen from the male part of the flower (stamen) to the female part of the same or another flower (stigma)

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20
Q

what is sexual selection?

A

natural selection arising through preference by one sex for certain characteristics in individuals of the other sex

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21
Q

what is dispersal?

A

ecological process involving movement of individual(s) away from the population in which they were born to another location, or population, where they will settle and reproduce

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22
How do pollinators affect speciation rates?
enact mating events between plants and, in doing so, conduct gene flow across the landscape
23
How does sexual selection affect speciation rates?
could accelerate speciation via increased coevolution of male traits and female preferences in allopatric populations or if traits involved in mate recognition were under direct environmental selection
24
How does dispersal affect speciation rates?
species which disperse over larger geographical distances may have much higher speciation rates
25
Geologic Time Scale
system used by geologists, paleontologists, and other Earth scientists to organize and categorize Earth's history into distinct periods based on significant events, changes in life forms, and geological processes
26
Stratigraphy
branch of geology that deals with the study of rock layers, or strata, and their relationships within the Earth's crust and involves the analysis, interpretation, and correlation of sedimentary, volcanic, and metamorphic rock layers to reconstruct the geological history of a region
26
Strata
layers of sedimentary rock that contain fossils and other evidence of past life, formed over time through the accumulation and compaction of sediments, such as sand, mud, and organic matter & usually studied for evolutionary history
27
Sedimentary Rock
one of the three main types of rock found on Earth's surface, formed through accumulation, compaction, and cementation of sediments derived from the weathering and erosion of pre-existing rocks, minerals, and organic materials
28
Radiometric Dating
technique used to determine the age of rocks, fossils, and other geological materials based on the decay rates of radioactive isotopes
29
Radioisotopes
isotopes of chemical elements that exhibit radioactive decay & essential components of radiometric dating methods because they decay at known rates, allowing scientists to calculate the age of geological samples based on the proportions of parent and daughter isotopes present
30
Half-life
time it takes for half of the radioactive atoms in a sample to decay into stable daughter atoms, specific to the particular decay process
31
when was the Hadeon eon?
4.6 billion years ago (Earth's formation) to about 4 billion years ago
32
when was the Archean eon?
spans from about 4 billion years ago to 2.5 billion years ago
33
when was the Proterozoic eon?
spans from 2.5 billion years ago to 541 million years ago
34
Subduction (Convergent) Boundary
type of tectonic boundary where two lithospheric plates move towards each other and one of the plates(oceanic) is forced beneath the other plate(oceanic or continental) and sinks into the Earth's mantle
35
when was the Phanerozoic eon?
current geological eon spanning from 541 million years ago to the present day
36
Divergent Boundary
type of tectonic boundary where two lithospheric plates move away from each other and as the plates separate, magma from the mantle rises to fill the gap, creating new oceanic crust along mid-ocean ridges or rift valleys on continents
37
Transform Fault (Plate) Boundary
type of tectonic boundary where two lithospheric plates slide past each other horizontally in opposite directions characterized by strike-slip faults, often associated with earthquakes but lack volcanic activity
38
Lithosphere
rigid outer layer of the Earth, consisting of the crust and the uppermost portion of the mantle, divided into tectonic plates that float and move on the semi-fluid asthenosphere beneath them
39
Asthenosphere
semi-fluid layer of the Earth's upper mantle beneath the lithosphere composed of partially molten rock material that flows slowly over geological timescales, facilitating the movement of tectonic plates
40
What is the continental drift theory?
theory proposed by Wegener that Earth's continents were once joined together in a single supercontinent called Pangaea and have since drifted apart to their current positions
41
What are some examples of climate change affecting the Earth and what happened due to these affects?
1. rising temperatures (changes in weather and precipitation patterns) 2. melting polar ice (rising sea levels, coastal erosion, loss of habitat) 3. loss of biodiversity (disrupted ecosystems, altering habitats) 4. impact on human health (increased heat-related illnesses, respiratory issues)
42
why does extinction occur?
Changes in environmental conditions, including climate (temperature, precipitation, snow and ice cover), ocean acidity, nutrient levels, and ocean oxygen levels
43
What is the allee effect?
phenomenon in biology characterized by a correlation between population size or density and the mean individual fitness of a population or species
43
what are fossils?
preserved remains or traces of ancient organisms that lived in the past
44
what are biota fossils?
collective fossilized remains of all the organisms that inhabited a particular ecosystem or environment during a specific period in Earth's history
45
what are flora fossils?
fossilized remains of plants and plant-related organisms that existed in ancient ecosystems
46
Hadeon Eon - major events
-formation of Earth -No life known -Cooling and solidifying of Earth's crust
46
what are fauna fossils?
preserved remains or traces of ancient animals and animal-related organisms that once inhabited Earth
46
Proterozoic Eon - major events
46
Ordovician Eon - major events
-First land plants, primitive fungi, sea weed appear. -Diverse marine life: corals, molluscs, bivalves, echinoderms, etc.
46
Archaean Eon - major events
Oxygen levels rise as a result of photosynthetic organisms -First eukaryotes (single-celled algae): 1.4 billion years old -earliest life, anaerobic prokaryotes (bacteria, archaeans) originated 3.5 billion years ago
46
Ediacaran Eon - major events
-supercontinent Pannotia formed -significant tectonic activity
46
Devonian Eon - major events
-First amphibians. -Extensive radiation of fish, land plants. -Many corals, brachiopods and echinoderms.
47
Proterozoic Eon - major events
-Origin of multicelled organisms. First sponges, colonial algae and soft-bodied invertebrates
47
Cambrian Eon - major events
-Rise of all major animal groups. -Metazoan life abundant; trilobites dominant. -First fish. No known terrestrial life.
47
Ordovician Eon - major events
47
Silurian Eon - major events
First spiders, scorpions, centipedes, early insects, vascular plants, jawed fish and large reefs appear.
47
Carboniferous Eon - major events
-First reptiles, cockroaches and mayflies appear. Extensive coal swamp forests. Sponge reefs. -Echinoderms, bryozoans dominant in oceans. Early winged insects. First coal swamp forests.
48
Jurassic Eon - major events
Dinosaurs and gymnosperms dominate the land; feathered dinosaurs and birds appear. Radiation of marine reptiles.
48
Permian Eon - major events
Gymnosperms, amphibians dominant. Beetles, stoneflies appear. Major extinction of 95% of marine species and 50% of all animal families.
48
Triassic Eon - major events
Origin of mammals, dinosaurs and true flies. Less diverse marine fauna.
49
Cenozoic Eon - major events
-MOST RECENT: Rise of civilization and agriculture. Extinction of large mammals in northern hemisphere. -Modern humans appear. Four major glaciations cause rapid shifts in ecological communities. Extensive radiation of flowering plants and mammals. First hominids appear. -Coevolution of insects and flowering plants. Dogs and bears appear. -Worldwide tropical rainforests. Pigs, cats, and rhinos appear. Dominance of snails and bivalves in the oceans. -Early mammals abundant. Rodents, primitive whales and grasses appear. -EARLIEST: Early placental mammals appear; first primates; modern birds.
49
Cretaceous Eon - major events
Marsupials, ants, bees, butterflies, flowering plants appear. Mass extinction of most large animals and many plants.
50
what is lateral gene transfer?
the movement of genetic information across normal mating barriers, between more or less distantly related organisms
51
three known mechanisms of lateral gene transfer
transformation, transduction, and conjugation Transformation - the acquisition of naked DNA by a recipient cell Transduction - the acquisition of DNA via virus intermediaries, which may infect one host, recombine with its genome and pick up some genes that can then be transferred to a 2nd host Conjugation - transfer of large DNA segments via specialized plasmids mobilized between cells through pili
52
What is the difference between prokaryotes vs. eukaryotes structure?
pro: much smaller than eukaryotic cells, have no nucleus, and lack organelles eu: membrane-bound nucleus, a central cavity surrounded by a membrane that houses the cell's genetic material, a number of membrane-bound organelles, compartments with specialized functions that float in the cytosol
53
difference between prokaryote and eukaryote cell wall structure
pro: all prokaryotic cells are encased by a stiff cell wall, maintains the cell's shape, protects the cell interior, and prevents the cell from bursting when it takes up water eu: have cell walls very rarely, wall made up of cellulose
54
prokaryote vs. eukaryote reproduction
pro: asexual and usually takes place by binary fission eu: asexually through mitosis and sexually through meiosis and gamete fusion (fertilization)
54
difference between Gram-positive and Gram-negative bacteria
gram-positive: bacteria that give a positive result in the Gram stain test, which is traditionally used to quickly classify bacteria into two broad categories according to their type of cell wall gram-negative: bacteria that do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation
55
where can you find archaea?
hot springs, hydrothermal vents, solfataras, salt lakes, soda lakes, sewage digesters
56
where can you find bacteria?
soil, water, plants, animals, radioactive waste, deep in the earth's crust, arctic ice and glaciers, and hot springs
57
what is the shape of coccus bacteria?
gram-positive bacterium/archaeon that has a spherical, ovoid, or generally round shape
57
what is the shape of bacillus bacteria?
gram-positive rod-shaped bacteria, a member of the phylum Bacillota, with 266 named species
58
what is the shape of spirillum bacteria?
curved-shaped bacteria which can range from a gently curved shape to a corkscrew spiral, gram-negative
59
8 major bacterial groups
1. Firmicutes: thick cell walls 2. Cyanobacteria: photosynthetic 3. Proteobacteria: diverse pathogens 4. Chlamydiae: obligate intracellular parasites 5. Actinobacteria: filamentous growth 6. Spirochaetes: spiral-shaped 7. Bacteroidetes: abundant in the gut 8. Planctomycetes: unique features (compartmentalized cells and budding reproduction)
60
5 major archaean groups
1. Euryarchaeota: methanogens, halophiles, and thermophiles 2. Crenarchaeota: extremophiles that thrive in hot, acidic environments 3. Korarchaeota: less well-known group of archaea found in hot springs 4. Thaumarchaeota: ammonia-oxidizing archaea in diverse environments 5. Nanoarchaeota: small, symbiotic archaea that live in high-temperature environments
61
What is the significance of biofilms?
key reason for the contamination of medical devices and the generation of microbial and chronic infections in the body
62
How do microbiomes affect eukaryotic health?
help you digest food, protect against infection and even maintain your reproductive health
63
what are viruses?
-microscopic infectious agents that are smaller and much simpler in structure compared to bacteria, archaea, and eukaryotic microorganisms -lack the cellular machinery necessary for independent metabolism and reproduction -viruses are considered obligate intracellular parasites
63
use of antibiotics and probiotics
-antibiotics: medicines that fight bacterial infections in people and animals -probiotics: live microorganisms that are intended to have health benefits when consumed or applied to the body
64
What are the characteristics of viruses?
genetic material: DNA (or) RNA capsid: protective protein coat envelope: lipid membrane from host host specificity disease causation evolution: high mutation rates and rapid evolution
65
what is negative and positive sense?
'sense' RNA is the blueprint for protein synthesis, while 'antisense' RNA, also known as Negative Sense RNA, has a sequence complementary to this and can't be directly translated into proteins
66
what is a retrovirus?
type of virus that inserts a DNA copy of its RNA genome into the DNA of a host cell that it invades, thus changing the genome of that cell
67
what is a mimivirus?
genus of giant viruses, genes responsible for cellular processes, such as protein translation and metabolism
68
what is a bacteriophage?
virus that infects and replicates within bacteria and archaea, kill and selectively target bacteria
69
what is phage therapy?
way of delivering virulent phages to a clinically ill patient to rapidly kill pathogenic bacteria
70
definition of vaccine
-biological substances that provide active immunity to specific infectious diseases by stimulating the immune system to recognize and remember pathogens, such as viruses or bacteria -typically composed of weakened, killed, or fragmented forms of the microorganism or its toxins, or they may contain specific components that mimic the pathogen
71
vaccine purposes
-prevention of disease: body's immune response to recognize and eliminate pathogen in the future -herd immunity: occurs when most of the population is immune to a disease, thereby reducing spread and protecting individuals who are unvaccinated or unable to receive vaccines due to medical reasons -public health impact: reducing burden of infectious diseases, preventing complications/deaths, and lowering costs of treating preventable diseases
72
vaccine advantages
-prevention of infectious diseases -safe and cost-effective compared to treatment of disease -long-term protection against diseases -eradication and control of diseases and outbreaks
73
vaccine disadvantages
-adverse reactions: allergies or local reactions -vaccine hesitancy fueled by misinformation -logistical challenges in storage/transportation during limited-resource periods or mass vaccinations

biology (6 decks)

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