Biological Classification & Diversity Lecture

Question-and-Answer flashcards covering cladograms, the three-domain system, characteristics of major kingdoms, plant divisions (bryophytes to angiosperms, monocots vs dicots), and distinguishing traits of representative animal phyla.

What is a cladogram used to illustrate in evolutionary biology?

The phylogenetic relationships among organisms based on shared derived characteristics.

Which microbiologist proposed the three-domain system using DNA sequencing?

Carl Woese.

Name the three domains in the current biological classification system.

Archaea, Bacteria (Eubacteria), and Eukarya.

List the six widely accepted kingdoms of life.

Archaebacteria, Eubacteria, Protista, Fungi, Plantae, Animalia.

What key cellular feature do all prokaryotes lack?

A membrane-bound nucleus.

Why are Archaea difficult to study in the laboratory?

Many can only be detected through analysis of their nucleic acids rather than traditional culturing.

On what major structural differences are Eubacteria distinguished from Archaea?

Cell-wall composition, nucleotide structure, and ribosome shape.

Why is Kingdom Protista considered paraphyletic?

It is a miscellaneous group of microorganisms that do not fit into Plantae, Animalia, or Fungi.

Into what two major divisions is Kingdom Protista traditionally split?

Algae (plant-like) and Protozoa (animal-like).

Give three distinguishing features of fungi.

Lack chlorophyll, are heterotrophic (saprotrophic), and possess cell walls made of chitin.

What term describes the feeding strategy of most fungi?

Saprotrophic (obtaining nutrients from decaying organic matter).

Name the four major fungal phyla.

Chytridiomycota, Zygomycota, Ascomycota, Basidiomycota.

Which fungal phylum includes yeasts and truffles?

Ascomycota (the sac fungi).

Which fungal phylum contains the typical mushrooms seen above ground?

Basidiomycota (the club fungi).

State two key traits of Bryophyta (mosses, liverworts, hornworts).

They are non-vascular and lack true roots, stems, and leaves.

Why are bryophytes usually confined to moist terrestrial habitats?

They lack vascular tissue and rely on water for reproduction and nutrient transport.

What reproductive structure do Pteridophyta use instead of seeds?

Spores.

Which plant group shows a clear alternation between sporophyte and gametophyte generations?

Pteridophyta (seedless vascular plants such as ferns).

What major innovation distinguishes Tracheophyta from earlier plant groups?

The production of seeds that house an embryo.

How do gymnosperms differ from angiosperms in seed development?

Gymnosperms produce naked seeds on cones, whereas angiosperms enclose seeds within flowers and fruits.

List the three main gymnosperm phyla.

Cycadophyta, Ginkophyta, Coniferophyta.

What key reproductive structure defines angiosperms?

The flower, with the female ovary developing into a fruit.

In which numeric multiples are monocot flower parts typically arranged?

Multiples of three.

How many cotyledons does a dicot seedling possess?

Two cotyledons.

Describe the leaf-vein pattern typical of monocots.

Parallel venation.

How are vascular bundles arranged in the stems of dicots?

In a ring (circular arrangement).

What type of root system is characteristic of monocots?

A fibrous root system.

Give three key characteristics of phylum Porifera (sponges).

Sessile, filter-feeding, lacking true tissues and symmetry.

Differentiate the medusa and polyp forms in cnidarians.

Medusa is free-swimming and umbrella-shaped; polyp is cylindrical and often sessile or colonial.

Name two general characteristics shared by all cnidarians.

Aquatic habitat (mostly marine) and the presence of stinging cells (cnidocytes).

What soft-bodied invertebrate phylum possesses a mantle and often a radula?

Phylum Mollusca.

List the four major classes of molluscs with one example each.

Cephalopoda (octopus), Polyplacophora (chiton), Gastropoda (snail/slug), Bivalvia (clam).

State two key traits of platyhelminths (flatworms).

Unsegmented, flattened body with a mouth but no anus; many are parasitic.

How can nematodes (roundworms) be morphologically recognised?

Uniformly cylindrical, tapered at both ends, unsegmented bodies.

What structural feature distinguishes annelids from other worm phyla?

Segmented body with chaetae (bristles).

Give four hallmark characteristics of arthropods.

Chitinous exoskeleton, jointed appendages, segmented body, molting (ecdysis).

Name five arthropod classes.

Crustacea, Insecta, Arachnida, Diplopoda, Chilopoda.

What unique water-based system aids movement in echinoderms?

The water vascular system with tube feet.

List three general characteristics of echinoderms.

Internal calcareous skeleton, radial symmetry in adults, marine habitat.