Diversity Unit Notes

Diversity Unit Notes

1. Taxonomy & Species Concepts (Pg, 24 - 37)

1. Two Major Cell Types: Prokaryotic and Eukaryotic cells are so different, that they represent a major division in the structural diversity of life. 

• Prokaryotic = “before the nucleus”

• A smaller type of cell that does not have a membrane-bound nucleus or organelles.

• Most ancient types of cell

• Examples include Bacteria and Archae 

• Eukaryotic = “true nucleus”

• A larger complex type of cell allows for specialization and multicellular life.

• They have a membrane-bound nucleus

• They  are 1000x larger than prokaryotic cells 

2. Kingdoms and Domains 

• Domain

• Largest Taxon

• Scientists have grouped all organisms into 3 domains, Bacteria, Archaea, Eukarya 

• Based on analysis of their rRNA 

Domain: Eukarya 

~ Animila don’t have a cell wall because we move

~ Plants put all their resources into strength and growth

~ Autotrophs make their own food through photosynthesis and sometimes non-living substances 

~ Heterotrophs get nutrients and energy from consuming other organisms 

3. Kingdom Characteristics 

• Species Diversity: the variety of and abundance of species in a given area  

• Genetic Diversity: the variety of heritable characteristics (genes in a population) 

• Ecosystem Diversity: the variety of ecosystems in a biosphere  

4. Species Diversity 

• More species create a more efficient ecosystem

• Increases biomass production 

• Biomass is a renewable organic matter derived from plants and animals 

• Biomass provides important clues about the health of an ecosystem 

• Better resistance to invasion of diseases 

5. Genetic Diversity (smallest scale)

• Diversity within a population is referred to as a gene pool 

• The number of different genes (traits) within a species is always greater than within a population

• Diversity leads to better disease resistance, prevention of extinction 

• Populations that lack genetic diversity are more susceptible to the disease than those that have high diversity. If none of the individuals in a population can survive the disease, the entire population could be eliminated. 

• Eg. Since 1996 the Tasmanian devils have been suffering from a contagious cancer, which has spread through biting, which eventually leads to death. Also helps species survive challenging environmental conditions 

6. Ecosystem Diversity (largest scale)

• Ecosystems consist of biotic and abiotic factors

• Ecosystems provide many services to the planet, the greater number of ecosystems means more protection for the services that provide

• Eg. gas supply, water supply, food, pollination, erosion control 

7. Key Terms 

• Structural Diversity: a type of biological diversity that is exhibited in the variety of structural forms in living things, from internal cell structures to body morphology. 

2. Simple Life – Viruses to prokaryotes and archaea (Pg 59 - 70)

1. A virus is a structure that contains strands of DNA or RNA surrounded by a protective protein coat: it can not live independantly outside the cell. 

• The parasite must invade cells and use its host cells' organelles for survival and reproduction 

• They do not metabolize energy 

• They can not do mitosis or binary fission

• Each virus can only affect a certain type of cell 

• Bacteriophage: viruses that infect bacteria. To control a bacteria cell scientists can modify a Bacteriophage structure. 

2. Types of viruses 

• SARS-COVID-19: specific to the respiratory tract

• Rhinovirus: prevents antibody reactivity with receptors. Upper respiratory tract specificity 

• HIV: dormant, attacks T-cells, retrovirus 

• Ebola: deadly disease, slower than the flu or HIV, attacks the immune system 

3. Naming and Classification: 

• Naming is usually based on what the virus infects or what disease it causes 

• Bacillus (bacilli p.l.) Coccous (cocci p.l.) Spirochetes 

Tubes Spheres Has a spiral look 

• Prefixes: chains → strep to 

• Prefixes clump → Staphlo 

• Prefixes one → mono

4. Gram Stain - Identifying Bacteria Virtual Lab

• Gram Positive

• Gram-positive bacteria retain the stain 

• Stains purple (traps the crystal violet-iodine)

• They are less pathogenic 

• Have a thick cell wall/ peptidoglycan layer  

• No outer membrane 

• Eg. Staphylococcus, is found on the skin and in the nose. 

• Gram Negative

• Gram-negative bacteria do not retain the stain

• Stains pink 

• They are more harmful

• Eg. pneumonia

• Thin peptidoglycan cell wall

• Has an outer membrane 

5. Viral Reproduction 

• Lytic Cycle: the replication process in viruses in which the virus’s genetic material uses the copying machinery of the host cell to make new viruses 

• Causes immediate disease symptoms

• RNA viruses only reproduce via the lytic cycle, they cannot join with the host DNA; the RNA acts like mRNA to create protein production  

• Some  viruses are lytic at a reduced rate, the flue virus is released one at a time

• The entire replication process occurs in the cytoplasm of the host cell 

• Order of the Lytic Cycle

1. Attachment: proteins on the surface of the virus bind to protein receptors on the surface of the host cell’s membrane 

2. Insertion: The virus injects genetic material (RNA and DNA) into the host cell

3. Replication: the host cell makes more viral DNA or RNA and proteins 

4. Assembly: new viral particles are assembled 

5. Lysis (release): the host cell breaks open and releases new viral particles 

• Lysogenic Cycle (remains dormant)

• Reproduction of the viral genome without killing the host cell  

• After DNA injection into the host cell, the viral DNA incorporates itself into the bacterial genome

• A prohage or provirus → bacteria genome or eukaryote genome 

• This reproduces along with the bacterium

• Stress/ environmental factors can trigger a lytic cycle

• Retroviruses - RNA viruses which convert their RNA to DNA so viral DNA can join with host DNA

• Eg. HIV is never lytic, the changes host cell functioning 

6. Comparing reproduction 

• Binary Fission (only in bacteria)

•  Asexual form of reproduction

• When a cell divides into two genetically identical slides

• Makes a copy of its original single chromosome

• Results on 2 genetically identical cells 

• Conjunction 

• A process in which there is a transferred through a long tube-like pilus

• Produces cells with new genetic information

• Cells bridge together to transfer chromosomes

7. Endosymbiosis

• Theory that explains how eukaryotic cells evolved from the symbiotic relationship between two or more prokaryotic cells.

• Merger of 2 simple prokaryote-like cells

• One cell engulfs a different type of cell

• Believed that these organelles are all the ancestors of one free-living prokaryote 

• Two eukaryote organelles present strong evidence of endosymbiosis in early eukaryotes 

• Eg. Chloroplast → converts solar energy → sugar and Mitochondria → extracts energy in stored sugar

• Endosymbiont: a cell that is engulfed by another cell in endosymbiosis

• Host cell: a cell that engulfs another cell in endosymbiosis 

8. Key terms:

• Capsid: the outer layer that surrounds the genetic material of a virus 

• Methanogenesis: a biological (or chemical) process that produces methane as a by-product 

3. Species and Naming (Pg. 10 - 22)

1. Species: a group of organisms that can interbreed in nature and produce fertile offspring

2. Species Concepts

• Morphological - structural features (body shape, size, and features) (The problem with this concept is that the organism might not be what it appears to be)

• Biological - the ability to have offspring that can survive  

• Phylogenetics relies on how related they are through evolution and history. Through DNA within cells to determine if they are the same species. The problem with this is that we don’t know the evolution and history of everything 

• Eg, Two monets in different parts of the world (they are different)

• Biological problems: we can’t tell if they can make offspring 

• All three have drawbacks which is why scientists use a combination of them

3. Linnaean Taxonomy 

• Used to minimize confusion 

• Binomial Nomenclature (each species has two names (genus + species) in Latin

• Classification: certain criteria must be met to fit within a certain genus and the species 

4. Taxonomic Classification 

• Nested classification system 

• A series of criteria must be met at each level 

• Allows for more sub-division 

• Constantly changing (there are 8 in totoal)

• Cordata = nervous system (organized)

• Domain (3) → Kingdom(6) → phylum → Class → Order → family → Genus → species (most specific)

5. Evidence of Relationships 

• Trying to establish evolutionary relationships 

• Anatomy: similar structure (physical) 

• Physiology: how your body works to keep you alive. Making similar proteins.

• DNA: Similar DNA sequence and amount of DNA

6. Phylogenetic Trees 

4. Dichotomous Key

• An identification tool consisting of a series of two-part choices that lead the user to a correct identification

• Sequentially narrows down the possibilities until a single species remains 

5. Eukaryotes – The Kingdoms (Protista and Fungi) (Pg, 72 - 78)(105 - 110)

• Stephanie Tsinokas - Protists and Fungi worksheet - Google Docs

1. Eukarya = Multicellularity 

• The idea that cells come together and work in groups 

• Have single-celled ancestors twice as old 

• This led to the development of specializations 

• Nutrition absorption 

• Information gathering 

2. Different Groups of Protists:

3. Fungi (decomposers)

• Yeast is unicellular (the majority are multicellular)

• Largest organism mycelium 

• All are heterotrophs

• They release digestive enzymes into their surroundings, then absorb the digestive nutrients 

4. Fungi Nutrition 

• Parasitic: living host (Eg. Cordyceps)

• Predatory: Trap prey (Eg. Arthobotry)

• Mutualistic: Works with organisms in a partnership. Help make protein at a very high level (the only way nitrogen gets into the cycle)

• Saprobial: most common, dead organic matter. 

5. Life cycles

• Diploid: most organisms are diploid meaning they have 2 sets of chromosomes. One paternal and one maternal.

• Haploid: a single set of chromosomes, called a gamete (sperm or egg) 2 Haploids make 1 Diploid.

• Humans have 46 chromosomes. Miosis cuts the chromosomes in half. 

6. Reproduction Fungi

• Single cells use bubbling (the baby cell is smaller than the mom cell)

• Some use fragmentation (rip into two)

• Most use sporulation (spores float in the air until they land)

7. Lichen 

• House tiny things inside it

• Composite organism

• Formas a relationship with a photosynthetic organism like green algae or cyanobacterium

• Can live in hard environments

• Many uses 

6. Eukaryotes – Plantae & Animalia (Pg. 90 - 124)

• Stephanie Tsinokas - Plants and Animals worksheet - Google Docs

1. Algae

• The evolutionary link between protists and plants

• Brown and Red are almost certainly protists

• Green is sometimes referred to as a plant

2. The Shift to Land 

• Must have protection from desiccation

• Transportation of water

• Slow process

• Start out in moist environment and is unable to grow in height for a prolonged period

3. Adaptations

• Plant Embryos: Seed – to protect and nourish the embryo

• Vascular Tissue: Allow the development of leaves and roots and allow growth to great heights

• Alternation of Generations: Gametophyte and Sporophyte

4. Non-vascular plants – Bryphytes 

• Rely on diffusion and osmosis to obtain water and nutrients

• Grow in mats on the ground and hold water very well

• Rhizoids anchor plants to the ground

• All go through alternation of generations, haploid gametophyte dominates time

• Mosses – Bryophyta 

• Short vertical stems, with leaves one cell thick

• Bogs, tundra, shaded areas

• sphagnum

• Liverworts - hepatophyta

• Appear leafy, still one cell thick

• More horizontal than vertical

• Moist shady environments; rocks, trees, rotten wood

• First to colonize disturbed areas

• Hornworts - Anthocerophyta

• One chloroplast per cell

• Sporophyte grows in a horn shape

• Tree trunks, river banks, damp locations

• Small diversity

5. Seedless Vascular Plants

• Ability to grow tall evolves

• Sporophyte dominates life cycle

• Gametophytes live for short period, relying on moist environments to reproduce

• Some of the original types still exist today

• Whisk Ferns - Psilotophyta

• Moist tropical environments

• No leaves or roots

• Photosynthesis in stem

• Spores dispersed by the wind

• Club Mosses - Lycophyta

• Woodland environments, mainly tropical

• Small needle like leaves

• Wind-dispersed spores

• Horsetails - Sphenophyta

• Most environments

• Hollow stems

• Scale like leaves

• Spores from end of stems

• Ferns - Pteridophyta

• All environments

• Roots, stems and leaves

• Leaves are curled at first

6. Seed Producing Vascular Plants

• Allow reproduction without water

• Can survive without water for years

• Travel in a variety of ways

• Develop as temperatures drop and spore-producing

• plants die off

7. Gymnosperms and Angiosperms

8. Flowers

9. Fruits

• Sweet fruits

• Burrs

• Floatable

• Wind born

10. Monocots vs. Dicots

h) Animal Classification 

• Backbone or not

• Level of organization

• Symmetry of body plan

• Body cavity

• Segmentation

• Movement

• Reproduction

• Invertebrates – Sponges & Cnidarians

• No backbone

• Only two layers of cells (unique)

• Sponges

• Asymmetrical body plan

• Individualized cells (can reform when fragmented)

• Sessile as adults

• Filter feed as water flows over them

• Cnidarians

• Radial body symmetry

• Do have tissues

• Capture prey by stinging

• Two body forms: polyp and medusa

• Invertebrates - Worms

• No backbone

• Basic tissues and organs

• Three layers of cells

• Some are segmented

• Very different body plans

• Invertebrates - Molluscs

• Bilateral symmetry

• Three layers of cells

• A coelom

• Two body openings

• Soft body protected by a hard shell

• Invertebrates – Echinoderms

• Radial symmetry

• Spiny endoskeletons

• Tube feet

• Water vascular system

• Invertebrates - Arthropods

• Largest animal phylum

• Legs are made of jointed movable parts

• Segmented

• Hard exoskeletons

• Vertebrates - Fish

• Gills to obtain dissolved oxygen

• Two classes: Cartilaginous – sharks and rays + Bony – salmon, tuna

• Vertebrates - Amphibians

• Live a portion of their life cycle on land

• Most are able to breathe through their skin

• Most reproduce with external fertilization

• Two major classes: Frogs and Toads + Salamanders

• Vertebrates - Reptiles

• Body scales to create waterproof barrier

• Lungs for breathing

• Internal fertilization, shelled eggs

• Three major groups: Lizards and snakes + Turtles + Crocodilians

• Vertebrates - Birds

• Endothermic with a 4 chambered heart

• Most can fly

• Feathered wings, hollow bones, toothless skull

• Very closely related to reptiles

• Scaled hind legs

• Skeletal similarities

• Vertebrates - Mammals

• Have mammary glands

• Produce hair

• Endothermic

• Four chambered heart

• Highly developed brain