The Diversity of Biological Organisms and Cladistics

Flashcards covering biological diversity, cladogram interpretation, monophyletic vs. polyphyletic groups, relationships between fungi, animals, and plants, and eukaryotic life cycles.

What are the three primary ways used to organize and compare life's diversity?

1) Phylogeny , 2) Organism traits, and 3) Reproduction and life styles.

What does the term "phylogeny" mean?

Evolutionary relationships among organisms.

What is cladistics?

The science of classifying organisms by their evolutionary relationships

What are cladograms?

A graphic representation of evolutionary relationships among lineages of organisms.

What does a branching point (node) indicate on a cladogram?

a recent common ancestor / RCA

Do adjacent branches on a cladogram indicate that one group directly gave rise to another?

No; adjacent branches indicate a common ancestor, not that one group evolved directly from the other.

How do derived traits differ from ancestral traits?

Derived traits are brand-new traits that evolved in a recent common ancestor and have never existed before, whereas ancestral traits are traits that existed previously.

What defines a clade?

A group of organisms that evolved from one common ancestor. (Monophyletic)

Which eukaryotic kingdoms are considered clades?

K. Fungi, K. Plantae, and K. Animalia.

Why are protists classified as a polyphyletic group rather than a monophyletic clade?

They have many different recent common ancestors

They don’t belong to K. Fungi, Plantae, or Animalia.

Why are fungi more closely related to animals than to plants?

Both store food as glycogen, their molecular data and biochemistry, both make chitin, and both lack plastids.

Why are fungi more closely related to animals than to plants?

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Both store food as glycogen (plants store ____), their molecular data and biochemistry, both make chitin, and both lack plastids (which means they __can/can’t__ _____ unlike ______ ).

Both store food as glycogen (plants store starch), their molecular data and biochemistry, both make chitin, and both lack plastids (which means they do not photosynthesize).

What specific biochemical similarity between animals/humans and fungi was highlighted in the notes?

Enzymes present in human and animal eye tearducts are also found in fungi.

What organism is considered the most recent common ancestor of all animals?

a) Choanoflagellates. It is of plant lineage.

b) Charophytes. It is a protist lineage.

c) Fungi. It is a fungi lineage.

d) Choanoflagellates. It is a protist lineage.

e) Charophytes. It is a fungi lineage.

d) Choanoflagellates. It is a protist lineage.

What organism, shown here under the microscope, is identified as the most recent common ancestor of all fungi? (GIVE BOTH ITS NAME AND ITS CLADOGRAM NAME)

Nuclearia (a nucleariid).

Which group of green algae is recognized as the most recent common ancestor and closest relative of land plants?

Charophytes

Which of the following are considered charophytes.

a) cyanobacteria

b) zygnema

c) nuclearia

d) chara

e) green algae (?)

b and d

Between chlorophytes and charophytes, which is more distantly related to land plants?

Chlorophytes.

According to the cladogram of eukaryotic life, did humans evolve from Protists, Kingdom Animalia, Kingdom Fungi, or none of the above?

Protists (ancestral single-celled protists from which animals arose).

From which did humans evolve?

a) nonancestral multi-celled protists

b) ancestral multi-celled protists

c) ancestral single-celled protists

d) nonancestral single-celled protists

e) nonancestral protists

c

What organism is depicted here?

Choanoflagellates

What would be the recent common ancestor of charophytes and land plants?

a)

b)

c)

d) An ancestral charophyte.

e)

d) An ancestral charophyte.

In standard biological life cycle diagrams, what ploidy do structures above and below the dividing line represent?

All structures above the line are haploid ($1N$), and all structures below the line are diploid ($2N$).

Where does mitosis occur in a diplontic life cycle, and what multicellular organism results?

Mitosis occurs after the zygote forms, resulting only in a multicellular diploid ($2N$) organism (characteristic of animals).

Where does mitosis occur in a haplontic life cycle, and what multicellular organism results?

Mitosis occurs after haploid spores are formed by meiosis, producing only a multicellular haploid ($1N$) organism (found in fungi and most protists).

Where does mitosis occur in a sporic life cycle (alternation of generations), and what multicellular organisms result?

Mitosis occurs twice—after spores are produced and after the zygote forms—resulting in both multicellular haploid (gametophyte) and multicellular diploid (sporophyte) organisms (found in all plants and many algae).