Diversity of Living Things- Booklet 1

What is a species?

A group of organisms that can interbreed in nature and produce fertile offspring.

What are species concepts?

Scientists have created different ways to define what a species is, and each one looks at a different characteristic of the organisms to help decide if they belong to the same species.

What is the Morphological Species Concept?Define morphology.

Defines species based on body shape, size, and structural features (morphology-The study of the structure or form of organisms.).

What is the Biological Species Concept?

Defines species by the ability to interbreed and produce fertile offspring.

What is the Phylogenetic Species Concept? Define phylogeny.

Defines species based on evolutionary history (phylogeny-The evolutionary history of a species.).

What is taxonomy? Who is the Father of Taxonomy and what did he develop?

The science of identifying, naming, and classifying species based on natural features. Carolus Linnaeus; developed binomial nomenclature.

What is binomial nomenclature?

A two-part scientific naming system: Genus (capitalized) + species (lowercase), italicized (e.g., Homo sapiens).

What is classification?

Grouping organisms based on criteria to organize and show evolutionary relationships.

What is hierarchical classification?

Organisms are classified from most general (unested classification)to most specific categories, often using nested groups.

What are taxonomic categories?

Levels or groups used to sort and organize living things, from very broad groups (like animals) to very specific ones (like a certain species).

What is a rank and a taxon?

A rank is each level in the classification hierarchy; a taxon is the name of a specific rank.

What is the broadest taxonomic rank?

Domain – groups organisms based on cell type; includes Bacteria, Archaea, and Eukarya.

Which domain does the grey wolf (Canis lupus) belong to and why?

Eukarya – it has complex, eukaryotic cells with a nucleus.

What are the 8 main taxonomic ranks (from broadest to most specific)?

Dear King Phillip Collected Orchids For Grandma Sophie

Domain, Kingdom, Phylum-- spine/ no spine (chordata phylum- all animals w/ a spine), Class- ex. Mammal, Order-ex: carnivore, Family, Genus, Species.

What is the classification of the grey wolf (Canis lupus)?

• Domain: Eukarya

• Kingdom: Animalia

• Phylum: Chordata

• Class: Mammalia

• Order: Carnivora

• Family: Canidae

• Genus: Canis

• Species: lupus

What does each lower rank in classification tell us?

It includes fewer organisms and shows more specific similarities.

How do taxonomists classify organisms today?

Using morphological, physiological, and DNA evidence.

What is morphological evidence?

Comparing physical structures (e.g., bones).

What is physiological evidence?

Comparing internal functions and biochemistry (e.g., proteins)

What is DNA evidence in classification?

Comparing DNA sequences to determine relatedness.

How does understanding phylogeny help in science?

Helps trace disease transmission and develop treatments.

How did the number of kingdoms change over time?

• 2 (Plants, Animals) →

• 3 (added Protista) →

• 4 (added Bacteria) →

• 5 (added Fungi) →

• 6 (split Bacteria into Bacteria & Archaea)

What are the 6 current kingdoms?

Animalia, Plantae, Fungi, Protista, Bacteria, Archaea.

What’s the difference between unicellular and multicellular organisms, and between prokaryotic and eukaryotic cells?

• Unicellular organisms are made of one cell (usually prokaryotic, like bacteria).

• Multicellular organisms are made of many cells (usually eukaryotic, like animals and plants).

• Prokaryotic cells: no nucleus, simple structure (found in Bacteria and Archaea).

• Eukaryotic cells: have a nucleus and complex structures (found in animals, plants, fungi, and protists).

Why was the domain category added?

Differences between Bacteria and Archaea were so large they needed ranks above kingdom.

What is binary fission?

A form of asexual reproduction where bacteria or archaea split into two identical cells. It's the most common method of reproduction and does not increase genetic diversity.

What is conjugation in bacteria and archaea?

A form of horizontal gene transfer where two cells form a bridge (pili) and one sends a plasmid (loop of DNA) to the other, increasing genetic diversity.

When does conjugation usually occur?

In unfavorable or harsh conditions, to increase the chance of adaptation through DNA exchange.

How are conjugation and binary fission connected?

After conjugation (DNA transfer), the recipient cell undergoes binary fission to produce genetically diverse offspring.

How is conjugation different from binary fission?

• Conjugation: Sexual, involves DNA transfer, increases diversity.

• Binary fission: Asexual, no DNA exchange, produces identical cells.

What is horizontal gene transfer?

The movement of genetic material by the pili (connect the 2 cells)between cells (not from parent to offspring), like in conjugation. It allows cells to gain new genetic traits.

What are plasmids?

Small, circular loops of DNA that carry extra genes and are transferred during conjugation.

What are methanogens?

Archaea that live in anaerobic environments and produce methane gas (C6H10O6 →CH4 +CO2 +H2O+2ATP). live in guts of cattle, landfills, and sediments of swamps.

What are extremophiles?

Archaea that thrive in extreme environments (e.g., very hot, acidic, or salty conditions). Includes:

• thermophiles-heat lovers(ex. methanopyrus)

• acidophiles- acid lovers (ex. picrophilus)

• halophiles- salt lovers (ex. haloccus)

what is a mesophile?

most bacteria that live in ,moderate conditions

What is aerobic respiration?

A process that requires oxygen to break down glucose, used mostly by eukaryotes.
Equation:
C₆H₁₂O₆ + O₂ → CO₂ + H₂O + 36 ATP(energy humans use)

What is anaerobic respiration?

A process that does not use oxygen, mostly done by prokaryotes(eg. bacteria and archea).
Equation:
C₆H₁₂O₆ → CH₄ + CO₂ + H₂O + 2 ATP
(Less efficient – produces less ATP)

How do aerobic and anaerobic respiration differ in ATP production?

• Aerobic: Produces 36 ATP (more efficient)

• Anaerobic: Produces 2 ATP (less efficient)

What is an autotroph?

An organism that produces its own food for energy (means “self-feeder”).

What are unicellular fungi called and what do they look like?

Yeasts – oval or cylindrical single cells.

What are hyphae?

Thread-like filaments that make up the body of multicellular fungi.

What is a mycelium?

A branching network of hyphae that lives in soil or decaying material.

What is the fruiting body of a fungus?

The visible, spore-producing reproductive structure.

Are fungi more closely related to plants or animals?

Animals, based on DNA evidence.

How do fungi digest food?

They release enzymes externally, then absorb nutrients.

What are parasitic fungi?

Fungi that absorb nutrients from living hosts.

What are predatory fungi?

Soil fungi that use specialized mycelia to trap and consume prey.

What are mutualistic fungi?

Fungi that form partnerships (e.g., mycorrhiza) with plants or protists.

What is mycorrhiza?

A mutualistic relationship between fungal mycelia and plant roots.

What are saprobial fungi?

Decomposers that absorb nutrients from dead or decaying matter.

How do fungi reproduce asexually?

By producing spores, budding (yeasts), or fragmentation.

What is budding in yeasts?

A small cell grows off the parent, then separates to form a new individual.

What is fragmentation in fungi?

A piece of mycelium breaks off and grows into a new fungus.

What are protists?

Mostly unicellular eukaryotes that don't fit other kingdoms but resemble animals, plants, or fungi.

What are the 3 major types of protists?

Animal-like, plant-like, and fungi-like.

How do animal-like protists get food?

They are heterotrophs, feeding on other organisms, organic wastes, or through parasitism.

What structures do Cercozoans(Phylum Cercozoa) use to move and feed?

Pseudopods (false feet-temporary cytoplasm extensions). They lack a cell wall, have a flexible membrane, and change shape.

Where do amoebas live? Eg of Cercozoans

Saltwater, freshwater, mud, and as parasites inside animal hosts.

Example of a Cercozoan and its effect on humans?

Entamoeba histolytica(living in human digestive system) causes amoebic dysentery by feeding on the small intestine lining.

What helps ciliates(Phylum Ciliophora) move and eat?

Cilia, small hair-like projections. cilia used for locomotion and sweeping food particles into the large complex unicellular organism.

What do flagellates(Phylum Zoomastigina) use for movement?

One or more flagella.

What relationship do flagellates have with termites?

Mutualism – they digest cellulose for termites in exchange for shelter and nutrients.

Are sporozoans(Phylum Sporozoa) mobile?

No – they lack cilia, flagella, and pseudopodia.

What is the life cycle of sporozoans like?

Alternates between asexual and sexual, often between two hosts.

Which disease is caused by sporozoans, and what is the pathogen?

Malaria, caused by Plasmodium species. carried by mosquitoes

malaria lifecycle

Sporozoites are injected by mosquitoes, travel to the liver, invade liver cells & RBCs, causes hemolysis(RBC destruction) and reproduce asexually to start the malaria infection.

What key feature allows plant-like protists to photosynthesize?

Chloroplasts.

What is unique about their nutrition(plant like protists)?

Many are mixotrophs—they can switch between photosynthesis and consuming food.(both autotrophic and heterotrophic)

What do unicellular plant-like protists form in aquatic ecosystems?

Phytoplankton.

What are the 3 main types of unicellular plant-like protists (phytoplankton)?

Dinoflagellates, Euglenoids, and Diatoms (Phylum Chrysophyta).

Diatoms characteristics

diatoms are Unicellular protists with rigid cell walls made of silica. The cell wall is made of two unequal parts, like a box with a lid—one smaller part fits inside a larger part. Most diatoms reproduce by asexual reproduction.

Prions: structure & uniqueness

• An infectious particle that causes damage to nerve cells in the brain and appears to consist mostly or entirely of a single protein

• The infectious agent remained infectious even when the DNA/Rna was destroyed by radiation

What is the structure of a virus?

A capsid (protein shell) filled with nucleic acid (DNA or RNA).

Do viruses have cells or organelles?

No; viruses have no cells and no organelles.

Can viruses reproduce on their own?

No, they require a host to reproduce. (invade host cell and reproduce there)

How do viruses infect a host?

They connect to specific receptors on host cells to enter, then take over the cell’s production.

What kind of organisms can viruses infect?

Viruses cause disease in plants and animals.

Are viruses considered living?

No, they are non-living according to the definition of life.

What are viruses classified by?

1. Capsid shape

2. Reproduction method

Give examples of virus shapes and types.

• Many-sided (20–80 sides) = Polio

• Sphere-shaped = HIV

• Cylindrical (with DNA/RNA) = TMV (Tobacco Mosaic Virus)

• Head with protein tail = T4 (infects bacteria)

What is a provirus?

A virus genome that is integrated into host DNA but is inactive and doesn’t kill the cell.

What is a retrovirus?

A virus with RNA instead of DNA that uses reverse transcriptase to become part of the host DNA.

What is reverse transcription?

The process of turning RNA → DNA, allowing virus DNA to connect to host DNA.

What is integrase?

An enzyme found in HIV and other retroviruses.

How are viruses used in biotechnology?

Scientists insert a gene into virus DNA → virus infects host → host makes many virus copies, each carrying the target gene.