Bio1220L: Practical One

Unit 1: Dichotomous keys

• Dichotomous keys: Organized couplets that consist of mutually exclusive characteristics

  • two types of dichotomous keys

    • Bracketed Keys

      • 1. Flowers Red…. …… …… ……2

      • 1’ Flowers not Red…. ….. ….. ….3

      • 2. Plant Herbaceous ………Species A

      • 2’ Plant Woody………………Species b

    • Indented Keys

      • 1. Flowers red

        • 2.Plant herbaceous ………..Species A

        • 2’ Plant Woody…………….Species B

      • 1’Flowers not red

        • 3. Leaves simple…………..Species C

        • 3’ Leaves compound……..Species D

Unit 2: Phylogenetic Trees and Microscopes

• Phylogenetic trees aid in inferring phylogenies based on these characteristics:

  • morphological

  • anatomical

  • reproductive

  • developmental

  • molecular

• 

• Monophyletic Groups

  • also called Clades

  • Group of organisms that descended from the same common ancestor

• Polyphyletic Group

  • group of organisms descended from different common ancestors

• Paraphyletic Group

  • group of organisms descended from a common ancestor but does

    not include all descendants of the common ancestor

• Homologous traits/synapomorphies

  • traits that are shared between organisms that derived from the same common ancestors

• Symplesiomorphies

  • traits shared between all organisms in a given phylogenetic tree

    • RNA, DNA, Proteins, Cell Membranes

• Analogous Traits

  • convergent evolution

  • Occurs when organisms share traits, but not the same common ancestor

Microscopes

Compound Microscope (what we use)

• magnifies up to 2000x

• has two lenses

• transmits a focused light through a specimen

• In order to calculate magnification

  • 10 x lens magnification

Unit 3: Population Genetics

• Evolution: a change in the genetic composition of a population over time

  • Population: a group of organisms of the same species that occur in the same area and interbreed or share a common gene pool

  • Gene Pool: genes available in a population

• Genetics: study of genes, genetic variation, and heredity

• Hardy-Weinberg Equilibrium

  • a model showing the frequencies of alleles in a population will stay the same regardless of starting frequencies under 5 certain conditions

    • 1. No mutation of genes

    • 2. Completely random mating

    • 3. Large population size

    • 4. No gene flow

    • 5. No natural selection

  • Allelic frequency

    • p + q = 1

      • p = frequency of dominant allele

      • q = frequency of recessive alleles

  • Genotypic Frequency

    • p² + 2pq + q² = 1

      • p² = frequency for homozygous dominant

      • 2pq = frequency for heterozygous

      • q² = homozygous recessive

  • Evolutionary Forces: natural selection, mutations, genetic flow

    • Occurs due to outside stimulus and new characteristics are maintained because traits are beneficial for a species

Unit 4: Bacteria & Archaea

• Gram Negative

  • Stains pink due to low peptidoglycan poor walls

• Gram positive

  • Stains purple due to peptidoglycan rich walls

• Shannon Index

  • Checks how diverse an ecosystem is

  • H’ = sum of p ln(p)

• Species Richness

  • Are there many species

  • S = sum of all species

  • H max = ln(S)

    • The higher the number, the higher the species richness

• Species Evenness

  • Are the species well spread out

  • Checks for abundance of each species

    • J = H’/Hmax

• species diversity

  • Dependent on species evenness and species richness

  • If species richness and species evenness are both high, then high species diversity

  • Low species diversity exists if:

    • There is low species richness

    • high species richness and low species evenness

• Similarities between bacteria and archaea

  • No cell walls, just cell membranes

  • Typically use cilia or flagella to move around

  • they are smaller than eukaryotes

  • they are extremophiles

  • use a variety of metabolic process for acquiring carbon and energy

  • unicellular with very little cell specialization, decompartmemtalized

    • known as generalists

• Differences between bacteria and archaea

  • 

Types of bacteria we need to know

• Clostridium

  • Gram positive or gram negative, rod shaped

  • Mostly gram positive

  • Perfectly rod shaped

  • Colonies: Feathery or a perfectly round circle

    

• Streptococcus

  • Gram positive, ball/round shaped

    

• Bacillus

  • Gram positive, rod shaped, shorter, put in chains

  • Looks like a tennis racquet

  • Colonies: smoother, irregular shaped

    

• Spirillum

  • Gram negative, spiral shaped, long and spirally

  • 

• Anabaena

  • Green, ball shaped, like a caterpillar

  • Cyanobacteria

  • 

• Mixed archaea

  • A mixture of both

    

Unit 5

• Climate Change

  • Caused by CO2 trapped in the atmosphere

  • Acidification of the ocean

  • Pace quickened due to human intervention

    • Fossil fuels

  • Effects

    • Loss of biodiversity

    • Species loss

    • More extreme weather

Unit 7

• Phenology

  • the timing of events in an organism’s life cycle

    • important events are timed to match resources

  • Can be annual, biennial, or perennial

    • Annual: They grow in one year before dying

    • Biennial: Complete life cycle in two years

    • Perennial: they live more than two years

• R² = how well data fits regression model

  • Coefficient of determination, determines how well y-hat can predict a new data point

• p-value

  • ANOVA test

  • Tells us if changes in data are due to chance or not

  • If less than 0.05

    • We reject null hypothesis

      • H_0

  • If greater than 0.05

    • We fail to reject the null hypothesis

      • H_A

      • Accepting the alternate hypothesis

  • Correlation is the relationship between variables

  • Regression describes how well y-hat can predict future data

Unit 8: Protists

• Protists are currently placed in Eukaryote Domain

• Three types of Protists

  • Animal Like

    • Heterotrophs

    • Unicellular

    • Found in freshwater habitats, sometimes marine or damp terrestrial

    • 4 main types based on movement

  • Fungus-Like

    • heterotrophs that feed on decompose organic matter

    • can be unicellular and multicellular

    • Terrestrial

      • found in shady and moist locations

  • Plant-Like

    • Autotrophic (photosynthesis)

    • Consists of unicellular

Animal Like

• Ciliated Protozoans (Paramecium)

  • Cilia for movement

  • Contractile Vacuole for expelling water from the cell

    

• Flagellated Protozoans (Trichonympha)

  • Move by beating their flagella

  • special because it has thousands of flagella

    

• Amoeboid Protozoans (Amoeba)

  • lack cell walls, very flexible

  • move and feed by extending pseudopodia (pseudopods)

  • Eat via phagocytosis

    

• Spore-Forming Protozoans (Plasmodium)

  • Parasites

  • are transferred from host to host via vectors

  • This one spreads malaria

    

Fungus-Like

• Plasmodial Slime Molds (Physarum)

  • Heterotrophs that feed on and decompose dead organic matter

  • 2 main types

    • cellular slime molds

    • plasmodial slime molds (This is our example)

    

Plant-Like

• Euglenids (Euglena)

  • Unicellular freshwater algae

  • autotrophic organisms

  • one flagellum

  • have a eyespot (stigma

    

• Dinoflagellates

  • Unicellular marine algae

  • two flagella

  • protective layer of cellulose

    

• Diatoms

  • Unicellular marine and freshwater algae

  • assume different body shapes

  • made of silica (glass)

  • forms chains or colonies

    

• Green Algae - Chlorophyta

  • Unicellular Freshwater (chlamydomonas)

    

  • Marine Multicellular (Ulva)

    • known as sea lettuce

      

  • Marine multinucleate (Codium)

    • known as dead man’s fingers

      

  • Multicellular Freshwater (Spirogyra, Cladophora)

    • Have filamentous morphology

    • 

  • Freshwater Colonial (Volvox)

    • each cell in the colony is identical, and could live independently of each other

    • Reproduces sexually and asexually

      

• Brown Algae (Phaeophyta)

  • Multicellular marine organisms

    • Kelp

      • Largest of all protists

      • grow in large kelp forests near the shore

        

    • Rockweeds

      • Grow in mats that can be seen draped

        

• Red Algae (Rhodophyta)

  • Multicellular marine organisms

  • often found deeper in the ocean than other algae