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BS110: Exam 2


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What are the Roles of Natural Selection?
1) All or non phenomenon
2) Gradula change in #s over time.
3) Affects distribution of individuals with characterstics w/in a population.
Types of Natural Selection?
1) Stabalizing
2) Disruptive
3) Directional
Stabalizing Selection?
Always in operation. Reduction in the numbers of individuals with extreme phenotypes and an increase in the numbers of individuals with intermediate phenotypes.
Disruptive Selection?
Increase in the number of individuals with extreme phonotypes and a decrease in the number of individuals with intermediate phenotypes.
Directional Selection?
INcrease in the number of indiviudals with an extreme phenotype due to the replacement of one allele or gene by another.
Types of Sexual Selection?
1) Intrasexual Selection
2) Intersexual Selection
3) Balanced Polymorphism
Intrasexual Selection?
Individuals of one sex of a species compete with individuals of the other sex of the same species.
Intersexual Selection?
Individuals of one sex of a species serve as a selection pressure on the other sex of the species.
Balanced Polymorphism?
The phenotypes of individuals in a population are maintaned in fairly stable proportions throughout generations.

(i.e. Snails of genus Cepaca. Individuals in the population exhibit lots of variation, and are eaten by birds. They exist in light to dark forms and with no bands to up to 5 bands...Even though certain ones are eaten in certain environments, they always reappear...)

Pleiotrophy/Heterozygous Advantage
Adaptations of populations of organisms to their physical environment: Clines?
A graded variation or gradual change in the trait or traits that follow a geoprahic distribution (Figure 28.8)
Adaptations of populations of organisms to their physical environment: Ecotypes?
Groups of distinct phenotypes in different habitats that make up species. (i.e. Black bears of North America)
Adaptions of populations of organisms to their biological environment: Coevolution?
Populations of two or more speicies are so closely interactionary that each population serves as a selection pressure on the other population, and adjustments/adaptations occur simultaniously (i.e. Predator-Prey Relationship)
Adaptions of populations of organisms to their biological environment: Aposemetism?
Dangerous/obnoxious species of organisms are made obvious to other organisms which are or maybe potential predators.
Adaptions of populations of organisms to their biological environment: Mimicry-Batesim?
One or more non-aposematic speicies resembles an aposematic species; and in doing so, gains protection.
Adaptions of populations of organisms to their biological environment: Mimicry-Mullarian?
Two or more aposematic species resemble one another in doing so "reinforce" the threat.
Adaptations of populations of organisms to their biological environment: Cryptic Coloration?
A type of camouflage that makes the potential prey difficult to detect against it's living/non-living background.
Patterns of evolutionary change: Convergent Evolution?
Two or more species or groups of organisms that are not closely related evolve similar adaptations or structures due to similar environmental selection pressures.
Patterns of evolutionary change: Parallelism?
Two or more species of organisms that ARE closely related evolve similar adaptations or structures due to similar selection pressures.
Patterns of evolutionary change: Divergent Evolution?
One population of organisms become separated or isolated from the other populations, and due to different environmental selection pressures, goes on a different evolutionary pathway. (i.e. Polar Bears evolving from Brown Bears)
Composed of one or more populations of actually or potentially interbreeding individuals. A taxonomic group of anatomically similar individuals. If species is composed of two or more populations, each population has a different gene pool and lives in a different environment.
Gene Pool?
All the alleles of all the genes in all of the individuals in a population.
Tempo of Speciation: Gradualism?
Evolution is a slow process with intermediate forms. The occurance of a major structure i sthe culmination of a few/several small structures.
Tempo of Speciation: Punctuated Equilibrium?
The Earth's history has been punctuated by brief periods of rapid speciation. No or few intermediate forms existed. Only quick changes in species.
Conservation Biology?
(1) Developed because of habitat destruction, reduction of the number of individuals and species.

(2) The study of the diversity and scarcity of life on the earth.

(3) Counteracts the biodiversity crisis (Reduction of Life).

(4) These scientists believe that there have been about 1.5 million species described and name. There are greater than 8 million species in existence.

(5) Believe all species should be inventoried.
Threatened Species?
A species that has a legal status declared by government because it is believed that they will become endangered. Enhanced protection.
Endangered Species?
A species that has a legal status declared by government because it is facing extinction. Enhanced protection and management.
Causes of Extinction?
(1) Habitat destruction/alteration.

(2) Overexpoitation of organisms.

(3) Exotic Species
Causes of Extinction: Overexploitation of Organisms?
(1) Excessive commercial harvest.

(2) Sport killing.

(3) Non-target species.
Exotic Species?
(1) Species that occur in an area and should not occur there. In contrast to native/endemic species.

(2) Kill native species/out compete.

(3) More than 4500 invasive species in U.S.

(4) Invade by car, boat, plane, smuggling.

(5) 30% of plant life/Agricultural (Cattle, sheep, wheat, soy beans)
Exotic Species in Great Lakes?
(1) Since early 1800s, >139 exotic species have become established in the Great Lakes: 59 plant; 24 algae; 25 fish; 14 mollusk. At least 13 (9%) have had impact.

(2) Lamprey, Goby Fish, Ruffe, Purple Loosestrife, Eurasian Milfoil, Siney Water Flea, Zebra Mussel, Rusty Crayfish.
Population Genetics?
Synthesis of Darwinian evolution and Mendelian genetics.
Hardy-Weinberg Equilibrium?
Under certain conditions, gene/allele frequencies and genotype frequencies remain the same from one generation to the next in populations of sexually reproducing organisms.

(1) Mutations are not occurring.
(2) Net movements of individuals not occurring.
(3) Population is large enough not to be affected by random changes in gene frequencies.
(4) Mating is random.
(5) Natural Selection not occurring.
(6) All offspring are equally likely to survive/reproduce.

Serves as a model with which we can compare natural populations. If our population does not conform to the HWE, one or more of these conditions is occuring.
Genetic Drift?
A change in the gene pool that takes place as a result of chance.
Founder Effect?
Small population that branches off from a larger population is not genetically representative of the larger population from which it was formed.
Genetic Drift: Population Bottleneck?
Population is dramatically reduced in numbers and the genetic variability of the population.
Why do ducks fly south for the winter?
(1) Religious: God gave ducks the ability to fly.

(2) Anthropomorphic: Ducks looking for a warmer environment. (Gives non-human species human characteristics.

(3) Teleological: Ducks need to go south to surivive.

(4) Natural Selection/Evolutionary: IN the past ducks that migrated produced more surviving offspring than those that did not.
Taxonomic Groups (Hierarchal Classification)?
Kingdoms, Phyla(um) = Division(s), Classes, Orders, Families, Genera(us), Species.
Scientific/Binomial Name?
Genus species
The classifying of organisms.
Methods and relationships used in taxonomy.
Schools of Systematics: Linnaeus (1700s)?
Established binomial naming system; system of branching categories based on the similarities and differences of species.
Schools of Systematics: Haeckel (1800s)?
Embryologist: Evolution as presented by Darwin.
Schools of Systematics: Phylogenetic?
Phylogeny + Geneology of major lines of descent and their relationships.
Schools of Systematics: Cladistics?
Evolutionary history and relationships of organisms in phylogenetic trees; based on sequential order in which branches arrive from a phylogenetic tree; branching points are marked by appearance of characteristics absent in ancestral condition; Biological changes that occurred since the groups branched from one another are not used.
Schools of Systematics: Molecular Taxonomy?
Biochemical techniques. An example includes looking for amino acid sequencing and proteins. Expensive to perform, but results are objectively quantifiable.
Monera: Prokaryotes or Eukaryotes?
Monera: Mode(s) of Nutrition?
Autotrophs and Heterotrophs.
Monera: Reproduction?
(1) Asexual: Doesn't involve formation and union of sex cells or gametes

(2) Sexual
Monera: Bacteria Reproduction?
(1) Fission: One bacterium splits into two.

(2) Conjugation: Two bacteria exchange genetic material.
Organism that lives in/on another organism (host); a parasite is metbollically dependant (gains nutrition) on the host; parasite gains protection from the host; parasite harms the host; host responds against parasite.
Parasitic Stages?
(1) Sticky capsules.

(2) Endospores (Stages which are resistent to our immune response; must be killed with chemicals, light, heat)
Parasitic Movement?
(1) Flagellum

(2) Cilia
Gram Stain?
Bacteria on a slide, stain in violet dye and treat with Iodine, alcohol washed, counterstain w/ Safranine.
Gram Stain: Gram Positive Bacteria?
- Color: Blue-Purple

- Rods, cocci, staphylococcus spp.

- Botulism, Food poisoning, Tetanus, Gangrene.

- Outer wall is composed of Peptidoglycant, which can be stained.
Gram Stain: Gram Stain Negative?
- Color: Pink-Red

- Spirochetes, cocci.

- Gohnerria, Chlamydias, Cyanobacterias.

- Peptidoglycant is within the cell wall, therefore it cannot be colored.
Gram Stain: Mycoplasms?
- Very small; lack cell wall; some are intercellular parasites (Pneumonia)
Gram Stain: Archaebacteria?
- Cell wall; no peptidoglycan; distinct lipids
Viruses: Characteristics?
- Small; poorly organized; obligate; intercellular parasites.

- Most are not susceptible to antibiotics.

- Can only reproduce within host cell.

- Some have an enzyme system (although not many are currently known to).

- Presence of DNA or RNA, single or double stranded, linear or circular.

- Four genes to hundreds of genes, capsid (protein coat) encloses genome.
Viruses: Diseases?
AIDS; Genital Herpes; Influenza.
Prokaryotic Cells?
- DNA is a large circular molecule.

- Genetic Material not within membrane.

- Only organelles are ribosomes.

- May/may not have cell wall.
Eukaryotic Cells?
- DNA is linear, forming distinct chromosomes; bound to protein called Histones.

- Contained within a nuclear membrane.

- Several Organelles

- Some have a cell wall.
Endosymbiotic Theory?
- Explanation on how Eukaryotic cells evolved from Prokaryotic cells.

(1) Prokaryotes took up residence inside another cell.

(2) Non-photsynthetic prokaryotes "incorporated" into cells, developed into Mitochondria.

(3) Photosynthetic prokaryotes became "incorporated" into cells, developed into plastid (chloroplasts).

(4) Nucleus originated via invagination (infolding) of plasma membrane that surrounded the protective DNA...Endoplasmic Reticulum.
Microscopic; eukaryotic; single-celled; colonial; auto/heterotrophs; parasitic.
Protista: Plant Like?
- Bacillariophyta and Euglenophyta

- Bacillariophyta (Diatoms)
- Aquatic
- Silica Cell Wall
- Chlorophyll + other pigments
- Mobile
- Diatomacious earth used in water filters, polishes, paints, paper, toothpaste.

- Euglenophyta
- 1 or more flagella
- Lack a cell wall
- Chlorophyll + other pigments
Protista: Protozoans-Rhizopoda?
- Rhizopoda
- Irregular Shape that continually changes.
- Move by structures called pseudopods (false feet).
- Phagocytosis (to eat cells); surround and engulf material.
Protista: Protozoans-Zoomastigophora?
- Animal-like flagellas

- One or more flagella.

- Lack cell wall/chlorophyll.

- Parasitic/Free living.
Protista: Protozoans-Dinoflagellata?
- Aquatic; 2 Flagella; Cell wall; Brown-red pigments; Neurotoxin (Shellfish can concentrate this toxin + are not affected).
Protista: Protozoans-Ciliophora?
- Mouth-like opening; Different nuclei; Free-living/parasitic; (Figure 28.14)
Protista: Protozoans-Apicomplexa?
- All intracellular parasites; Complex life cycles; No movement except male gametes in some species; Plasmodium spp produces Malaria.
Protista: Protozoans-Forominifera (Forams)?
- Aquatic (most saltwater); produce cells composed of protein + calcium carbonate; Pseudopods that move through tiny openings in the shells; form many beaches.

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