<<

Chapters 16-19: Diversity of

1. Taxonomic Classification 2. and 3. and Fungi

4. 5.

1. Taxonomic Classification

The Classification of There are ~1.5 million known on our planet. • total # or species on estimated to be anywhere from 7 to 100 million

To study so many organisms and their evolutionary relationships requires: • standard nomenclature • same name used worldwide for a given , system of classification • allows organization by “relatedness”

1 The Taxonomic Hierarchy Each level of the hierarchy is referred to as a taxa: eukarya Family hominids Species sapiens

The “Taxa”

The 3 Domains: Eukarya 4 Kingdoms Protists, Fungi, Plants & Animals of Eukarya:

Bacteria: • “common” prokaryotes

Archaea (or archaebacteria): • “unusual” prokaryotes or “” • thrive in harsh environments (acid, high salt, boiling…) Eukarya: • all organisms made of eukaryotic cells

Protists: single-celled Fungi: multicellular; absorb Plants: multicellular; photosynthesize Animals: multicellular; ingest food

2 2. Viruses and Prokaryotes

Viruses are Small, Simple, Non-living Consist of genetic material (DNA or RNA) inside a coat (may have a membrane envelope).

• no metabolic capabilities

• reproduce only within a

• frequently “lyse” or kill host

bacteria viruses euk. cell

Viruses come in Immense Variety Differ in: • size & shape • genetic material • DNA, RNA, double or single strand

• mode of

• host specificity

3 AIDS Infection

The AIDS virus is a : must convert RNA to DNA

Types of Prokaryotes Prokaryotes = single-celled organisms lacking nuclei and other Bacteria • live in every conceivable environment • immense variety of , • play many essential biological roles • nitrogen (all plants depend on it!) • (essential for recycling of ) • (gut in humans, ,…) Archaea • thrive in very extreme environments

Prokaryotes come in 3 Basic Shapes

spherical rod-shaped () ()

corkscrew-shaped ()

4 3. Protists and Fungi

Types of Protists Protists = most single-celled eukaryotic organisms • some can form multicellular aggregates • 2 basic types of :

1) (“first animals”) • (ingest food) • amoebae, paramecia, , trypanosomes • many are parasites • e.g., trypanosomes, (causes ) trypanosomes

2) (“photosynthetic protists”) • (, , ) • “seaweeds” diatoms

seaweed () volvox

5 The Fungi

Types of Fungi include:

• mushrooms

Key Characteristics of Fungi Fungi digest organic material externally (they don’t ingest food like animals do):

• secrete digestive , absorb food

• some are feeders (consume dead ) some are parasites (prey on living) • decomposition of dead is extremely important for (recycles nutrients)

Fungal cells have cell walls (made of )

Can reproduce sexually or asexually

4. Plants

6 What constitutes a ? Plants are multicellular, photosynthetic, and share characteristic modes of

Major plant phyla, classes

The Bryophytes

Liverworts

Mosses

Key features: • lack true , , stems • no internal vasculature

• rely mainly on • limits their size

The Tracheophytes

Tracheophytes are the vascular plants:

• contain vessels to transport material internally

There are 3 basic types of vascular plant:

• seedless vascular plants (e.g., , horsetails)

• gymnosperms (all “cone-bearing” plants)

• angiosperms (all flowering plants)

7 Seedless Vascular Plants Horsetails Ferns • most primitive vascular plant

Gymnosperms pine All “cone-bearing” plants: • (pines, firs, etc…), , gingko • seeds produced in cones juniper (not flowers)

gingko

Angiosperms All flowering plants: • produce seeds* in flowers (via fertilization of ) • disperse seeds via fruits *seeds are plant + nutrients within a seed coat • most dominant of plant

8 5. Animals

Invertebrates

Vertebrates

Characteristics of Animals All members of the Animal Kingdom: • are multicellular • consist of eukaryotic cells w/o cell walls • are heterotrophs • consume food derived from other organisms • feed by “ingesting” food • unlike fungi which “absorb” food externally Most members of the Animal Kingdom: • have a symmetrical • radial or bilateral symmetry • have distinct tissues, organs • reproduce sexually

Radial vs Bilateral Symmetry Radial Symmetry • symmetrical halves “no matter how you slice it”

Bilateral Symmetry • only one plane of symmetry

symmetry as viewed from the dorsal (back) or ventral (belly) sides

9 vs Vertebrate animals • have a backbone or “vertebral” column • less than 3% of known animal species Invertebrate animals • NO backbone or “vertebral” column • > 97% of known animal species • any “non-vertebrate” animal

The vertebrate/invertebrate distinction is somewhat “old school” They more or less constitute “sub-kingdoms”

Major Invertebrate Phyla “Lower” “Higher” Invertebrates

Porifera • all • all “segmented

Cnidarians Mollusks • anemones, , , ,

Platyhelminthes • all “” • , ,

Nematodes • all “roundworms” • , urchins

The Phylum Chordata Main characteristics of the Chordates: • have a notochord • usu. gives rise to the backbone during development • have a hollow cord • becomes brain & spinal cord during development • pharyngeal “gill slits” • may disappear during development • have a • may disappear during development ***All are chordates but not all chordates are vertebrates***

10 Major Classes

Agnatha • “jawless” , ,

Chondrichthyes (Aves) • cartilagenous fishes • ,

Osteoichthyes Mammals • bony fishes • humans, ,

Amphibians • ,

Key Terms for Chapters 16-19

• taxa, domain, kingdom, phylum… • bacteria, archaea, eukarya, fungi, protists • bacillus, coccus, spirillum • protozoa, algae • bilateral vs radial symmetry, vertebrate vs invertebrate

Relevant Review Questions: ch. 16 – 3, 6; ch. 17 – 3, 5, 9 ch. 18 – 1, 3-5, 7-15; ch. 19 – 3

11