Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
165 Cards in this Set
- Front
- Back
|
Which of these processes make allele
frequencies more similar among populations? A. Gene flow B. Natural selection C. Genetic drift D. Founder effect E. Mutations |
A- Gene flow
Gene flow has a homogenizing effect |
|
|
Which of the following statements is FALSE?
If gene flow ends: A. allele frequencies in isolated populations are free to diverge. B. populations begin to evolve independently of each other. C. and new mutation that creates a new phenotype, there is no way for that allele to appear in that other population. D. only natural selection can cause sufficient divergence for speciation to occur. E. mutations, selection and/or genetic drift can cause isolated populations to diverge sufficiently for speciation to take place. |
D- Only natural selection can cause sufficient divergence for speciation to occur.
False because natural selection is not the only mechanism for speciation to occur |
|
|
True or False?
Speciation results from genetic isolation and genetic divergence. Genetic isolation results in lack of gene flow. Genetic divergence occurs because selection, genetic drift and mutations proceed independently in isolated populations. |
True
|
|
|
What are the 2 greatest unifying ideas in modern biology and when were they introduced?
|
The Cell theory and evolution
Introduced in the mid 1800's |
|
|
Define evolution.
|
A change in characteristics of a population over time.
|
|
|
What are two important components of evolution?
|
Species are related by common ancestry (not independent entities created separately)
Descent by modification (species/populations can be modified) |
|
|
When was the Origin of Species created?
|
1859
|
|
|
What is common ancestry?
|
All species come from pre-existing species.
Theory of evolution predicts that biologists should be able to trace their ancestry. |
|
|
What do nodes on a tree represent?
|
Common ancestry
|
|
|
Define ecology.
|
Study of interactions among organisms (with one another) and with their environment
|
|
|
What is the Hardy-Weinberg Principle?
|
The theory that under 5 certain conditions, evolution would not occur and genetic equilibrium will be reached.
|
|
|
What are the 5 conditions that may be met in order for Hardy-Weinberg to occur?
|
Random mating
No natural selection No genetic drift (deals with the size of population) No gene flow (migration) No mutation |
|
|
Do humans rank high or low in genetic variation compared to other species?
|
Low in genetic variation
|
|
|
What is the difference between genotype and phenotype?
|
Genotype is the particular combination of ales present in individual
Phenotype is the expression of a physical, behavioral, biochemical trait |
|
|
What defines a species?
|
A group of individuals capable of exchanging alleles through reproduction
|
|
|
What is a gene pool?
|
All alleles present in a group of interbreeding individuals
|
|
|
What defines a population?
|
A group of interbreeding individuals in the same geographical region.
|
|
|
What is the ultimate source of genetic variation?
|
Mutations
|
|
|
What is independent assortment?
|
Mendel also found that each pair of alleles segregates independently of the other pairs of alleles during gamete formation.
|
|
|
What is crossing over and when does it occur?
|
The exchange of genes between homologous chromosomes, resulting in a mixture of parental characteristics in offspring.
This occurs at the stage when chromatids of homologous chromosomes pair up during synapsis, forming X-structure (chiasma). The chromatids break into segments (of matching regions), which are then exchanged with one another. Crossing over is important because it results in new combinations of genes that are different from either parent, contributing to genetic diversity. Occurs during Prophase I in Meiosis |
|
|
What is recombination?
|
Reshuffling during sexual reproduction mechanisms?
Major source of variation |
|
|
How do you calculate allele frequency?
|
# of copies of an allele/total # alleles in population
|
|
|
What does the Hardy-Weinberg Equilibrium principle predict?
|
It predicts genotypes frequencies from allele frequencies.
-Based on the probabilities of "picking" alleles (which depends on their frequencies) |
|
|
Define fitness.
|
The measure of an extent to which the individual's genotype is represented in the next generation.
Reflects reproductive success and Survival of offspring to reproduction |
|
|
What is positive selection?
|
Increases frequency of a favorable allele
If all other alleles are eliminated, the remaining allele is FIXED. (i.e, frequency = 100%) |
|
|
What is negative selection?
|
Decreases frequency of a harmful/deleterious allele?
|
|
|
What is balancing selection?
|
In addition to either eliminating or fixing alleles, natural selection can also MAINTAIN both alleles in a population/species.
Due to differences in environment favoring different alleles or heterozygote advantage |
|
|
What is an example of a heterozygote advantage?
|
Balancing selection due to heterozygote advantage
Heterozygote fitness is higher than either of the homozygotes (Results in both alleles maintained in a population at some intermediate frequencies) Example: Hemoglobin alleles A and S: in regions with malaria AS genotypes have an advantage over AA or SS. AS= protection from malaria thus both alleles maintained. |
|
|
Natural selection can cause three different types of patterns of selection. What are they?
|
Stabilizing
Directional Disruptive |
|
|
What is stabilizing direction?
|
Selects against both extremes.
|
|
|
What is directional selection?
|
Selection against one extreme
|
|
|
What is disruptive selection?
|
Selection against intermediate phenotype
The average sized ones die off and both extremes live |
|
|
How does sexual selection effect reproductive success?
|
It increases it
|
|
|
Sexual selection is expensive. What does it cost?
|
Time and energy
Building elaborate houses Coming up with different dances |
|
|
NATURAL SELECTION is the only what?
|
Natural selection is the only mechanism that leads to adaptations
|
|
|
What other mechanisms cause changes in allele frequencies?
|
Migration
Mutation Genetic drift |
|
|
What is significant about mutations?
|
Mutations are the ultimate source of variation, but it is very RARE. Not important as an evolutionary mechanism that causes allele frequencies to change
|
|
|
Describe genetic drift.
|
Random change in allele frequencies that is STRONGLY affected by population size.
Bottleneck and Founder's Effect |
|
|
What is bottleneck?
|
A population is reduced drastically due to natural disasters, overhunting, over harvesting, habitat destruction, etc.
Remember picture of bottle with red, blue, green and yellow marbles. Few marbles are randomly dumped into beaker Only blue and green marble appeared in beaker They continue to reproduce over the years to their original population size and other colors (or alleles) have disappeared |
|
|
What is the founder effect?
|
Establishment of a new population when a few individuals from a population start a new population with a different allele frequency than the original population.
Red and yellow bugs on the coast. Red bug flies to nearby island. Island becomes majority of red bugs |
|
|
What removes mutations?
|
Negative selection
|
|
|
What is the molecular clock?
|
The correlation between TIME of separation and the amount of genetic divergence.
|
|
|
What is carbon dating?
|
Technique used to determine the age of the fossil
|
|
|
What are histones?
|
Prokaryotes don't have stretched DNA, histones are the little beads.
Histones are the proteins closely associated with DNA molecules. They are responsible for the structure of chromatin and play important roles in the regulation of gene expression. |
|
|
What are introns?
|
Piece of DNA that doesn't code for anything.
It is removed before the protein is translated. |
|
|
Define species
|
Fundamental biological unit
Species are not fixed |
|
|
What is speciation?
|
The splitting event that creates two or more distinct species from a single ancestor.
It creates evolutionary independent populations When speciation is complete, a new branch has been added to the tree of life |
|
|
What is reproductive isolation?
|
Species are groups of actually or potentially interbreeding populations that are reproductively isolated from other such groups.
Is a mule a species? -No because they're sterile and can't make more mule |
|
|
What events stop gene flow?
|
Pre-zygotic
and Post-zygotic |
|
|
What is pre-zygotic?
|
Before zygote = Before FERTILIZATION
Prevents individuals from mating due to behavioral, physical, time (temporal) and space (ecological) problems |
|
|
What is post-zygotic?
|
After fertilization
Offspring of mating do not survive or reproduce usually due to genetic incompatibility |
|
|
What are the 5 reasons for pre-zygotic isolation?
|
Temporal- different breeding times (releasing pollen at different times of the year)
Habitat- Breed in different habitats (parasites that begins to exploit new host species are isolated from their original population) Behavioral- Courtship displays differ (to attract male fireflies, female fireflies give a specific sequence of flashes) Gametic barrier- eggs and sperm are incompatible (in sea urchins, a protein called binding allows sperm to penetrate eggs. Differences in the amino acid sequence of binding cause matings to fail between closely related populations. Mechanical-male and female reproductive structures are incompatible (Alpine sky pilots (flowering plant) the floral tube varies. Bees can pollinate in populations with short tubes but only hummingbirds can pollinate in populations with long tubes) |
|
|
What are the 2 reasons for post-zygotic isolation?
|
Hybrid Viability- hybrid offspring do not develop normall and die as embryos (when ring-necked doves mate with rock doves, less than 8% eggs hatch)
Hybrid sterility- Hybrid offspring mature but are sterile as adults (Eastern meadowlarks and western meadowlarks are almost identical morphologically, but their hybrid offspring are usually infertile) |
|
|
What is morphospecies?
|
The concept is practical and frequently used by biologists
Members of the same species look alike |
|
|
What is a ring species?
|
A series of neighboring populations resulting from gradual divergence.
Gene flow Population at the end can't directly interbreed because it became too diverged Gene flow between them possibly "indirectly" |
|
|
What does polymorphic and cryptic mean when referring to the morphospecies concept?
|
Polymorphism occurs when two or more clearly different phenotypes exist in the same population of a species.
A cryptic species complex is a group of organisms that are typically very closely related yet their precise classification and relationships cannot be easily determined. The morphospecies concepts creates confusion when dealing with the two statements above. |
|
|
What is an ecological niche?
|
A term describing the way of life of a species. Each species is thought to have a separate, unique niche
environment, habitat preferences, etc. |
|
|
What is allopatry?
|
A different homeland
Either by dispersal or Vicariance |
|
|
What is the 3 step process of allopatric speciation by dispersal?
|
Geographic- some guys disperse from their population and colonize a new habitat
Divergence- mutation, genetic drift, and selection cause new population to diverge from original one Genetic isolation- The two populations are genetically isolated from one another |
|
|
What is the 3 step process of allopatric speciation by Vicariance?
|
Geographic isolation- chance event physically separates population into subgroup
Divergence- isolated populations begins to diverge due to mutation, genetic drift and selection Genetic isolation- eventually the 2 populations are genetically isolated from each other |
|
|
What is sympatric speciation?
|
Instantaneous speciation that is cause by hybridization (chromosome numbers in progeny do not match the parental species which leads to reproductive isolation)
This is common in plants through polyploidy |
|
|
What does polyploidy mean?
|
Multiple sets of chromosomes
Duplication of chromosomes (a type of mutation due to error in meiosis) Polyploidy is the most common means of sympatric speciation |
|
|
What is auto-polyploidy and allo-polyploidy?
|
Auto- derived from unusual reproductive event between members of the same species
Allo- by hybridization of two species |
|
|
What is a genome?
|
The entire genetic material transmitted form parents to offspring.
|
|
|
What percent of total DNA is protein coding?
|
2.5%
|
|
|
What two things are not a good predictor of biological complexity?
|
Gene numbers and genome size
|
|
|
Compare the genomes of a human and a pufferfish.
|
Last shared common ancestor about 475 mya
25% human genes have no counterparts in Fugu Human Genome- 97% repetitive Fugu Genome- 6% repetitive |
|
|
Compare the genomes of a human and a mouse.
|
Last shared common ancestor about 75 mya
25,000 genes and share 99% 300 genes unique to each organism |
|
|
Compare the genomes of a human and a chimp
|
Most recent time of divergence: Last shared CA about 4.1-6 mya
Humans have fewer chromosomes 1% differences in nucleotide sequences |
|
|
The size of the genome is greatly affect by what?
|
The amount of non-coding DNA
about 97% DNA is not protein coding in humans |
|
|
Define phylogenies.
|
Evolutionary history of a group of organisms (evolutionary relatedness)
|
|
|
What is the basis of the endosymbiotic theory?
|
Mitochondria and chloroplasts originated as free-living bacteria
|
|
|
What does rooted mean?
|
The most ancestral branch in the tree
|
|
|
Define sister groups.
|
2 groups that are the closest relatives to each other. They share a common ancestor that is not shared by any other group.
|
|
|
What is a monophyletic group?
|
Includes and ancestral population and ALL of its descendants but no others
|
|
|
What is synapomorphy?
|
A shared derived trait that only occurs in the monophyletic group
|
|
|
What is homology?
|
Similarity of organisms due to common ancestry
|
|
|
What is a polyphyletic group?
|
UNNATURAL group that does not include the most recent ancestor
|
|
|
What is Homoplasy/Analogy?
|
Similarity of organisms resulting from convergent evolution.
|
|
|
What is a paraphyletic group?
|
A group that includes an ancestral population and SOME of its descendants but not all.
|
|
|
Name the classification of animals from highest to lowest.
|
Kingdom
Phylum Class Order Family Gensus Species Keep Pond Clean Or Froggy Gets Sick |
|
|
What is parsimony?
|
Approach that requires the smallest number of character changes...Provides the simplest explanation of eta supporting the simplest hypothesis to explain observations
|
|
|
Fossils are preserved mostly is which type of rock?
|
Sedimentary
|
|
|
When did the split happen? Slide
|
Divergence between humans and chimps: 5-7 MYA
During that time: molecular divergence of about 1% Humans are the sole survivors of all Homo lineages |
|
|
Why was bipedalism such a key innovation?
|
Freed up our ancestor's hands
|
|
|
What are the roles of prokaryotes in the ecosystem?
|
Photosynthesis
Nutrient cycling Nitrogen fixing Decomposition |
|
|
What is the role of prokaryotes in human society?
|
Diseases
Bioremediation Food Biotechnology Human body Human micro biome |
|
|
Bacterial cells out number our own cells by how much?
|
10-1
|
|
|
What are the oldest form of life known?
|
Prokaryotes
Oldest micro-fossils date to 3.5 BYA |
|
|
What were the first organisms to produce oxygen as by-product of photosynthesis?
|
CYANOBACTERIA
|
|
|
For about 1 million years, all oxygen in the Earth's atmosphere came from photosynthesis by cyanobacteria.
True or False? |
True
|
|
|
At least 50% of atmospheric oxygen comes from photosynthesis by microbes.
True or False |
True
|
|
|
What are microbes?
|
Bacteria and Algae
|
|
|
What is bioremediation?
|
Bacteria can clean up polluted sites
|
|
|
What are the three domains of life?
|
Eukarya
Archaea Bacteria All share a prokaryotic cell organization common ancestor |
|
|
Which two domains are more closely related?
|
Eukarya and Archaea
|
|
|
What are 5 main characteristics of bacteria?
|
No nuclear membrane
No mitochondria or other energy producing organelle No sexual reproduction DNA is single circular chromosome and plasmids Structural support is cell wall with peptidoglycan |
|
|
Bacteria:
no sexual reproduction no meiosis or recombination True |
True
|
|
|
How do bacteria achieve genetic diversity?
|
Horizontal Gene Transfer
-Conjugation -Transformation -Transduction (viruses) |
|
|
What is conjugation?
|
Exchange of genetic information via pious between two cells from donor to recipient cell
|
|
|
What is transduction?
|
Involves a virus that facilitates transfer of a piece of bacterial DNA to a newly infected cell
|
|
|
What is transformation?
|
Some cells take up DNA from their environment
|
|
|
Gram positive stains what?
Gram negative stains what? |
+ Purple
- Pink |
|
|
Cell is gram-positive if what?
|
Cell wall peptidoglycan
|
|
|
Cell is gram-negative if what?
|
Peptidoglycan and outer membrane make up the cell wall
|
|
|
What are 5 ways that archaea are distinct from bacteria?
|
Different composition of cell membrane
No peptidoglycan in cell walls Differences in DNA transcription apparatus Antibiotics ineffective against archaea Extremophiles |
|
|
What are extremophiles?
|
Archeaea that thrive in different environments than bacteria. Tolerate extreme conditions
|
|
|
What are the 2 major ways of obtaining carbon?
|
Synthesize their own carbon-containing compounds from inorganic CO2
Acquire carbon-containing compounds from other organisms |
|
|
What is an autotroph and what is a heterotroph?
|
Autotroph- make own carbon (food) from inorganic CO2
Heterotroph- Eat plants and animals (acquire carbon compounds from other organisms) |
|
|
What are the two major modes of ATP production?
|
Use of light energy
Use of chemical compounds |
|
|
What is a phototroph and what is a chemotroph?
|
Phototroph- use of light energy
Chemotroph- use chemical compounds |
|
|
How do eukaryotes differ from prokaryotes?
|
Larger
organelles More extensive cytoskeleton Nuclear envelope Multicellularity Reproduction -Bacteria and Archaea asexually by fission -Eukaryotes: Sexually (undergo meiosis) linear chromosomes , asexually by mitosis and cell division |
|
|
What is unique about protists?
|
They have no trait that is only found in protists and in no other organisms
|
|
|
What do protists resemble?
|
Early eukaryotes
|
|
|
What metabolic processes take place in which organelles of a eukaryotic cell?
|
Mitochondria- aerobic respiration
Chloroplasts- Photosynthesis |
|
|
What is the endosymbiosis theory?
|
Eukaryotic chloroplast originated when a protists engulfed a cyanobacterium. Once inside the protist host, the photosynthetic bacterium provided oxygen and glucose in exchange for protection and access to light.
|
|
|
What are the 4 key lineages of eukaryotes?
|
Animals
Plants Fungi Protists |
|
|
What are algae considered?
|
Photosynthetic protists
|
|
|
What are protozoa considered?
|
Heterotrophic protists
|
|
|
What is mixotrophic?
|
Both phototropic and heterotropic (combine photosynthesis and ingest food to satisfy nutritional needs)
|
|
|
How do some protists move to find food?
|
Crawl (slime molds, amoeba)
Swim using a novel type of flagellum or cilia *Eukaryotic flagella are completely different from prokaryotes, evolved independently |
|
|
What is the sister group to animals?
|
Choanoflagellates
|
|
|
What are opisthokonts?
|
The group name given to categorize animals, choanoflagellates, and fungi.
|
|
|
What are stramenopiles?
|
Dialoma (*?)
Brown algae Oomycetes |
|
|
What are alveolates?
|
Dinoflagellates
Apicompleants Cilates (***?) |
|
|
What are archaeplastida?
|
Glaucocystophytes
Red algae Green algae and land plants |
|
|
Archaeplastida include what protists and plants?
|
Red algae
Green algae Land plants |
|
|
What are 3 groups of single-celled organisms?
|
Prokaryotes
Most Protists Some fungi |
|
|
What group does fungus belong to?
|
Absorptive heterotrophs
-Decomposers -Mutualists -Parasites |
|
|
What are hyphae?
|
(Individual filaments of a fungus)
Fungal filaments permit to search for food because fungi have no means of locomotion Highly branched filaments Large surface ***Reproductive structures are also composed of hyphae |
|
|
What are hyphae cell walls made of?
|
Chitin
Therefore, they are flexible |
|
|
What are mycelia?
|
(Mass of connected hyphae)
A network of branched hyphae |
|
|
What can fungi use to be predatory?
|
Sticky hyphae or lasso-like hyphae
|
|
|
Fungi are primarily what?
|
Decomposers
|
|
|
What does it mean to be an absorptive heterotroph?
|
Secrete digestive enzymes into surroundings
Absorb molecules produced by external digestion |
|
|
Athlete's foot and ring worm are types of what?
|
Fungal infections
|
|
|
What is mutualism?
|
Both participants benefit
|
|
|
What is symbiosis?
|
Close association between species that have evolved over a long period of time
Enhance reproduction, population growth of both ecological partners |
|
|
What is obligate?
|
Both symbionts are ENTIRELY DEPENDENT on each other for survival.
|
|
|
What is facultative?
|
Both symbionts can, but don't have to live with other organisms but do better when together
|
|
|
What is the difference between endomycorrhizae and ectomycorrhizal fungi?
|
Endo- fungal hyphae penetrate the root cell walls
Ecto- penetrate between root cells but not through root cell walls |
|
|
What are lichens?
|
A composite organism, not a single organism even tho they function like one
Stable association of Photosynthetic sp of green alga or cyanobacteria |
|
|
What did fungi evolve from?
|
Aquatic, unicellular and flagellated ancestors
|
|
|
All green algae are what?
|
Haplonts
|
|
|
What are haplonts?
|
Organisms that are haploid throughout their entire life with the exception of a zygote that undergoes immediate meiosis to generate haploid spores.
|
|
|
What characteristics unite green algae and land plants?
|
-Photosynthetic pigments: chlorophylls a & b, carotendoids
-Cells walls with cellulose -Storage product: starch |
|
|
What are land plants?
|
Embryophytes
|
|
|
What is the alternation of generations:
|
Hetermorphic life history
Major difference between ancestral green algae and embryophytes |
|
|
What are the 3 things that make up bryophytes?
|
Liverworts
Moss Hornworts |
|
|
Bryophytes are mostly haploid gametophyte and haploid sporophyte.
True or False |
True
|
|
|
What does parazoa mean?
|
No tissues and no symmetry.
Asymmetrical |
|
|
What is eumetazoa?
|
Tissues organized into one of the two types of symmetry
Radial: Body parts arranged around central axis Bilateral: Body has right and left halves that are mirror images. |
|
|
What are protostomes?
|
"Mouth first"
Mouth develops from the blastopore |
|
|
What are deuterostomes?
|
"Mouth second"
The blastopore becomes the anus Humans |
|
|
What is a blastopore?
|
Opening to the outside
|
|
|
Protosomes consist of two groups. What are they?
|
Ecysozoans and Lophotrochozoans
|
|
|
What is gastrulation?
|
The key process during embryogenesis leading to establishment of germ layers
|
|
|
BILATERAL SYMMETRY ALLOWS FOR CEPHALIZATION
|
REMEMBER THAT BITCH
|
|
|
What are the four principle chordate features?
|
1) nerve chord
2) notochord- may be replaced by vertebral column 3) pharyngeal slits- pharyngeal pouches present in all vertebrate 4) postanal tail |
|
|
What fish has no muscles in its fins?
|
Ray-finned
|
|
|
What fish have fleshy muscular lobes and an amphibian ancestor?
|
Lobe-finned
|
|
|
What are the two jawless fishes?
|
Hagfish and lampreys
|
|
|
Amniotes include what types of animals?
|
Reptiles, birds and mammals
|
|
|
The amniotic egg has four membranes. What are they?
|
Chorion- protection, gas exchange
Allantois- collect wastes Yolk sac- nutrients Amnion- protection |
|
|
What are the 5 major plant hormones?
|
Auxins
Gibberillic acid Cytokinins Ethylene Abscisic acid |
