Chapter 18-Taxonomy

Taxonomy

The science of naming, describing, and classifying organisms

Species

organisms that can interbreed and produce fertile offspring.

Domain

The highest and most inclusive taxonomic category (Bacteria, Archaea, Eukarya).

Kingdom

A major category below domain (e.g., Animalia, Plantae, Fungi).

Phylum

The taxonomic rank below kingdom and above class (e.g., Chordata)

Eukaryote

Organisms with cells that contain a nucleus (e.g., animals, plants, fungi, protists).

Prokaryote

Organisms without a nucleus (e.g., bacteria and archaea).

Autotroph

An organism that makes its own food (e.g., plants).

Heterotroph

An organism that gets its energy by consuming other organisms (e.g., animals).

What are the major Phyla in the animal kingdom?

Chordata, Arthropoda, Mollusca, Annelida, Cnidaria, Platyhelminthes, Nematoda, Echinodermata, Porifera

Chordata phyla

animals with a backbone (e.g., mammals, birds, fish)

Arthropoda Phyla

jointed legs, exoskeleton (e.g., insects, spiders, crustaceans)

Mollusca Phyla

soft-bodied, often with shells (e.g., snails, octopuses)

Annelida phyla

segmented worms (e.g., earthworms)

Cnidaria phyla

stinging cells (e.g., jellyfish, coral)

Platyhelminthes phyla

flatworms

Nematoda phyla

roundworms

Echinodermata phyla

spiny-skinned (e.g., sea stars)

Porifera phyla

sponges

What type of symmetry do annelids have?

Bilateral symmetry – they can be divided into mirror-image halves on one plane.

Are annelids invertebrates or vertebrates?

Invertebrates – they do not have a backbone.

What kind of body structure do annelids have?

Segmented body with repeating units, a coelom, and setae (tiny bristles) in many species for movement.

How do annelids move?

By using muscles along with setae for anchoring and crawling.

What type of circulatory system do annelids have?

A closed circulatory system, where blood is contained within vessels.

How do annelids breathe?

Most breathe through their skin, which must stay moist for gas exchange.

What kind of digestive system do annelids have?

A complete digestive system with a mouth, pharynx, crop, gizzard, intestine, and anus.

How do annelids reproduce?

Most are hermaphrodites (have both male and female organs), but they typically reproduce sexually.

What is the ecological role of annelids?

Earthworms help aerate soil, decompose organic material, and recycle nutrients.

What type of symmetry do cnidarians have?

Radial symmetry – body parts arranged around a central point.

Are cnidarians invertebrates or vertebrates?

Invertebrates – they do not have a backbone.

What are cnidocytes?

Specialized stinging cells found on tentacles, used for defense and capturing prey.

What are nematocysts?

Stinging organelles within cnidocytes that inject toxins into prey or predators.

What are the two body forms of cnidarians?

Polyp (sessile, tube-shaped – e.g., coral) and Medusa (free-swimming, bell-shaped – e.g., jellyfish).

How do cnidarians eat?

They are carnivores that capture prey with tentacles and digest food in a gastrovascular cavity (one opening for both mouth and anus).

Do cnidarians have a nervous system?

They have a nerve net – a simple, decentralized network of nerve cells.

What is the ecological importance of cnidarians?

Corals build reefs, which are habitats for many species; jellyfish are key in ocean food webs.

What type of symmetry do arthropods have?

Bilateral symmetry – the body can be divided into mirror-image halves.

What is the arthropod exoskeleton made of?

Chitin – a strong, flexible material that provides protection and support.

What does "arthropod" mean?

It means "jointed foot" – referring to their jointed appendages.

What is the basic body plan of all arthropods?

segmented body, a tough exoskeleton, and jointed appendages

How do arthropods grow if they have a hard exoskeleton?

They must molt (shed the exoskeleton)

What type of circulatory system do arthropods have?

An open circulatory system – blood is not always in vessels.

How do arthropods breathe?

Insects: through spiracles (tiny holes on the sides of an insect’s body that let air in) and tracheal tubes (Small air tubes inside an insect that carry oxygen from the spiracles to the rest of the body)

Spiders: through book lungs

Crustaceans: through gills

What are some subgroups of arthropods?

• Insects (3 body parts, 6 legs)

• Arachnids (spiders, scorpions – 8 legs, 2 body parts)

• Crustaceans (crabs, shrimp – mostly aquatic)

• Myriapods (centipedes and millipedes)

What is the ecological importance of arthropods?

They are pollinators, decomposers, pest controllers, and a major food source for many animals.

what are appendages?

structures such as legs and antennae that extend from the body wall

Tracheal tubes (Arthropod respiratory structure) is used by…

most terrestrial arthropods

Book lungs (Arthropod respiratory structure) are used by…

spiders and others

Feather like gills (arthropod respiratory structure) are used by…

aquatic arthropods

book gills (arthropod respiratory structure) are used by…

horseshoe crabs

Seven Levels of Taxonomy:
(Dear King Philip Came Over For Good Soup)

• Domain

• Kingdom

• Phylum

• Class

• Order

• Family

• Genus

• Species

What is a Domain?

The broadest group; separates all life into three major groups: Bacteria, Archaea, and Eukarya.

What is a Kingdom?

A large group within a domain that shares basic traits (e.g., Animalia, Plantae, Fungi).

What is a Phylum?

A group of organisms with a similar body plan or structure (e.g., Chordata = animals with a backbone).

What is a Class?

A: A group within a phylum; organisms share more specific features (e.g., Mammalia = animals with fur and milk).

What is an Order?

A more specific group within a class; organisms share even more traits (e.g., Carnivora = meat-eating mammals).

What is a Family?

A group of closely related organisms within an order (e.g., Felidae = cat family).

What is a Genus?

A group of very closely related species (e.g., Panthera = lions, tigers, leopards).

What is a Species?

The most specific level; a group of organisms that can mate and produce fertile offspring (e.g., Homo sapiens = humans).

What is Eubacteria?

True bacteria; unicellular prokaryotes found everywhere (e.g., E. coli).

What is Archaebacteria?

Ancient bacteria; unicellular prokaryotes that live in extreme environments (e.g., hot springs, salt lakes).

What is Protista?

A diverse group of mostly unicellular eukaryotes; some act like animals, plants, or fungi (e.g., amoeba, algae).

What is Fungi?

Mostly multicellular eukaryotes that absorb nutrients from dead matter; decomposers (e.g., mushrooms, mold).

What is Plantae?

Multicellular eukaryotes that perform photosynthesis to make their own food (e.g., trees, grass, flowers).

What is Animalia?

Multicellular eukaryotes that are heterotrophs (eat other organisms) and usually have movement (e.g., humans, dogs, insects).

Who created Taxonomy?

Carl Linnaeus

Protosomes

organisms that form a mouth first in embryonic development

Deuterosomes

organism that form an anus first in embryonic development