Bio 112 Lab Exam 1 TAMU

population

All organisms of the same group or species that inhabit the same area and can interbreed

genetics

The study of how the characteristics of one generation are passed on to the next

genetic structure

Distribution of genotype frequencies within a population

evolution

The change in heritable characteristics of a population over generations

selection

The process whereby a genotype increases or decreases in frequency because it confers a benefit or a detriment to the organism, which results in differential survival.

genes

Consist of a specific DNA sequence the encodes the synthesis of a product (usually a protein)

allele

Different forms of a gene

genotype

The genetic make-up of an organism (i.e., AA or aa)

phenotype

The physical trait, appearance, or other characteristic of an organism as a result of genotype and the environment (i.e. black or red)

What is Hardy-Weinberg equilibrium?

HWE is observed when a population's allelic and genotypic frequencies do NOT change. In other words, there is no evolutionary force acting on the population

What are the assumption of HWE?

No Selection, No Gene flow, Random mating, Infinite population size, No mutation

Is it really possible for a population to be in HWE?

no

Why is Hardy-Weinberg used in population genetics?

It is used as a null model, or, in other words, as a point of comparison. By comparing real populations to HW, we can determine if they are evolving (and generally, at what rate)

What are the five evolutionary processes?

mutation, gene flow, genetic drift, natural selection, and sexual selection

Classify each of the five evolutionary processes as random or non-random.

Random: Mutation, Genetic Drift, (Gene Flow)

Non-Random: Natural and Sexual Selection, (Gene Flow)

Individuals that reproduce poorly in a population tend to emigrate the next year. In this scenario, is gene flow random or non-random?

This would imply that individuals with specific genotypes are emigrating. Thus, this is a NON RANDOM example of Gene Flow, which can be random or nonrandom.

Which of the evolutionary processes require genetic variation within a population in order to work?

Natural and Sexual Selection

The Founder's effect is an extreme type of which evolutionary process?

Genetic drift

Describe how you would expect the allelic and genotypic frequencies of a population to change when subjected to each of the five evolutionary processes (Genetic drift)

frequencies will change randomly - if the population is small enough, it may lead to the fixation of one of the alleles.

Describe how you would expect the allelic and genotypic frequencies of a population to change when subjected to each of the five evolutionary processes (Natural selection)

frequencies will change specifically to favour the "most fit" genotype, increasing the allele frequencies associated with that genotype. If homozygous recessive individuals have better camouflage, then the aa genotype will increase and the a frequency will increase.

Describe how you would expect the allelic and genotypic frequencies of a population to change when subjected to each of the five evolutionary processes( sexual selection)

like natural selection, but instead, imagine that the homozygous recessive has more colorful plumage.

Describe how you would expect the allelic and genotypic frequencies of a population to change when subjected to each of the five evolutionary processes (gene flow)

If gene flow is random, population frequencies will shift randomly after the loss/intake of individuals. Consider a population where AA reproduce poorly and emigrate. Over time, even if some AA individuals are produced, they will leave the population, causing allelic frequencies for AA in the "source" population to drop. However, AA will increase in the destination population (as well as A frequency).

Describe how you would expect the allelic and genotypic frequencies of a population to change when subjected to each of the five evolutionary processes (mutation)

If the mutation is deleterious, it will most likely be lost quickly and cause little/no change. However, if it is beneficial, the mutated genotype/allele frequencies can increase drastically.

We discussed two methods for deleterious alleles to persist in a population. What were these? Which applied to SCA?

-Heterozygote Advantage (This applied to SCA!)

-Recessive Refuge

What causes malaria? What cell in the human body is infected?

Malaria is caused by the protist Plasmodium, which infects the Red blood cell.

What is the vector (transmitter) of malaria?

It is carried or transmitted by the female Anopheles mosquito

What happens to rbc affected by the sickle-cell allele

they mutate into a crescent shape (instead of round)

Phylogenetics:

The study of the evolutionary history or relationships among organisms

clade

a group of organisms believed to be descended from a common ancestor.

plesiomorphic character

Ancestral; possessed by all organisms in a clade

apomorpic character

Derived; different from the form found in the ancestor; possessed by 1 or more organisms in a clade

synamorphic

derived and shared

autapomorphic

derived and unique

homologous

a shared trait among organisms due to identical descent (sharing a common ancestor)

Analogous

a similar trait that evolves independently among distantly or unrelated organisms as a result of adapting to similar environments

ingroup

the organisms of interest or the organisms being studied in a cladogram

outgroup

the reference organism or group of organisms (the "negative control").

"1" when constructing trees

1 means you have a DERIVED state, different from the OUTGROUP

"0" when constructing trees

0 means you have the ANCESTRAL state, the same as the OUTGROUP

What are the 3 domains of life?

Bacteria, Archaea, Eukarya

Define Horizontal Gene Transfer (HGT)

acquiring DNA from other, unrelated organisms

How does HGT affect the phylogeny of microorganisms?

This complicates the tree of microorganisms, making it more of a web than a strict tree

What are the magnifications of the objective lens on the microscope?

4x, 10x, 40x, 100x

What type of microscope did we use in lab?

compund

Calculate the total magnification for each lens.

Total magnification =objective lens x ocular lens

- So... 40x, 100x, 400x, 1000x

What are some defining features of bacteria?

No membrane-bound organelles (no nucleus), peptidoglycan in the cell wall

What are the three basic shapes found in bacteria?

coccus, bacillus, spirillum

What do cyanobacteria contain that allow them to photosynthesize?

thykaloids

What is the role of the two specialized cyanobacteria cells: heterocysts and akinetes?

Heterocysts: perform Nitrogen fixation

-Akinetes: spore-like, allow bacteria to survive harsh conditions

What is endosymbiosis?

the engulfment of another cell

What is the endosymbiotic theory?

An ancient eukaryote engulfed a bacteria/archae, which later became a mitochondria. A similar occurrence happened later with cyanobacteria, which became chloroplasts and other plastids.

What are some defining characteristics of archaea?

-Lack membrane-bound organelles (no nucleus)

-No peptidoglycan

-Unique branching hydrocarbons in the cell membrane allow survival in harsh conditions

In what environments are archaea often found?

harsh/extreme conditions (heat, slat, etc.)

What are some defining features of Protists?

-Have a true nucleus and membrane-bound organelles

-Large amount of variation in traits

What are the four main Supergroups?

Archaeplastida, Unikonta, SAR Clade, Excavata

Within each Supergroup (excluding Archaeplastida), what are the corresponding groups? (Unikonta)

Amoebozoan and Opisthokonta

Within each Supergroup (excluding Archaeplastida), what are the corresponding groups? (SAR clade)

Stramenopiles, Alveolates, Rhizarians

Within each Supergroup (excluding Archaeplastida), what are the corresponding groups? (Excavata)

Euglenozoa

Which group of Unikonta did we observe in lab?

Amoebozoa

What are some distinguishing features of Amoebozoan?

-Lobe or tube-shaped pseudopodia

-Free-living or parasitic

-Single, colonial, or multicellular

What are two example organisms of Amoebozoan?

Amoeba, slime molds

What are the three groups within the SAR Clade?

Stramenopiles, Alveolates, Rhizarians

Distinguishing feature of Stramenopiles

two flagella - one hairy, the other smooth

Distinguishing feature of Alveolates

membrane-enclosed sac (alveolus)

Distinguishing feature of Rhizarians

-Shells (tests)

-thin pseudopodia

example of an Stramenopile

Diatoms, Achyla

example of an Alveolate

Paramecium, Peridinium, Plasmodium

example of an Rhizarian

Feramniforans, Radiolarians

What are some distinguishing features of Excavata

Often have a "feeding groove" or "oral groove"

Name an example organism we looked at in lab from the Excavata group

Euglena

Classify: No nucleus, no peptidoglycan

archaea

Classify: Nucleus, feeding grove, flagellum

Excavata; Euglena

Classify: Nucleus, two flagella - one hairy, one smooth à

Stramenophile

Classify: No nucleus, thylakoids, colonial with heterocysts

cyanobacteria

Classify: Nucleus, membrane-bound sac

Alveolates

Classify: No nucleus, peptidoglycan à

Bacteria

Classify: Nucleus, shell made of calcium carbonate

Rhizarians; Foramniferans