Zoology Lecture Review: Science of Zoology, Animal Classification, and Architectural Patterns

Comprehensive Question and Answer flashcard deck covering Lectures 1 through 3 on Zoology, including fundamental theories, genetics, taxonomy, cladistics, grades of organization, symmetry, body planes, embryonic germ layers, and body cavity arrangements.

What is zoology and what Greek root words form its name?

Zoology is the scientific study of animal life. Its name is derived from the Greek words Zoo (meaning animal) and -logy (meaning study).

What two major scientific theories guide the study of zoology?

1. Evolution by natural selection
2. Mendelian inheritance

Approximately how many years ago did animals originate on the tree of life?

More than $600$ million years ago.

What are the five main characteristics of an animal defined in the lecture?

1. Has cells with a nucleus
2. Has cells that lack rigid cell walls
3. Has a body that lacks hyphae
4. Eats other organisms
5. Usually contains thousands of species of bacteria and archaea in its body

What is a microbiome and what is its primary role in animals?

A microbiome consists of the many species of bacteria and archaea living in an animal, especially in the gut. It helps with digestion and can be critical for survival (e.g., in cattle, termites, and corals).

Which two English naturalists independently conceived the theory of evolution, and what were their lifespans?

Charles Darwin ($1809$ to $1882$) and Alfred Wallace ($1823$ to $1913$).

What are the five separate theories that make up the theory of evolution?

1. Perpetual Change
2. Common Descent
3. Multiplication of Species
4. Gradualism
5. Natural Selection

What is perpetual change and what serves as evidence for it?

Perpetual change states that the living world is not constant or simply cycling back to the same conditions. Evidence comes directly from the fossil record.

What is common descent and what evidence supports it?

Common descent states that all life descends from a common ancestor. Evidence includes the homology of structures and conserved DNA.

What five conditions/requirements are required for natural selection to occur?

1. Variation among organisms
2. Some variation is heritable
3. Different variants do not produce the same number of offspring
4. Variants more likely to survive and reproduce leave more offspring
5. Their traits become more common in the population

How did peppered moths demonstrate natural selection during and after the Industrial Revolution?

Before the Industrial Revolution, light moths were much more common. During the Industrial Revolution, dark moths became much more common. After environmental cleanup, light moths became more common again due to shifting survival advantages.

What three inheritance laws were formulated by Gregor Mendel during his garden pea experiments?

1. Law of Dominance
2. Law of Segregation
3. Law of Independent Assortment

How are taxonomy and systematics defined using formulaic relationships?

Taxonomy = Classification + Nomenclature Systematics = Taxonomy + Phylogeny

How did Aristotle ($384$ to $322\text{ BC}$) classify animals?

He classified animals according to whether they had blood or no blood.

What are the seven mandatory taxonomic ranks established by Carolus Linnaeus, listed in order of decreasing inclusiveness?

Kingdom $→$ Phylum $→$ Class $→$ Order $→$ Family $→$ Genus $→$ Species

What are the key formatting rules for writing binomial nomenclature?

Every species receives a two-word Latinized name printed in italics (or underlined if handwritten). The first word is the Genus name and is capitalized; the second word is the species/specific epithet and is not capitalized.

Who developed the principles of phylogenetic systematics (cladistics) in the $1960\text{s}$?

Willi Hennig ($1913$ to $1976$), a German entomologist. His system is also called Hennigian systematics.

What four advantages of phylogenetic systematics are listed in the lecture notes?

1. Stable (only one actual evolutionary history)
2. Informative (shows how closely related organisms are)
3. Flexible (contains many nested levels beyond KPCOFGS)
4. Predictive (morphological or molecular traits help place new taxa)

What is the difference between an ancestral character and a derived character?

An ancestral character is the original condition present in the most recent common ancestor (MRCA). A derived character state arose during the evolution of a group and differs from the ancestral condition.

How is an outgroup used to infer character states in a phylogenetic tree?

An outgroup is a closely related species/group used for comparison. If both the outgroup and ingroup share a character state, it is considered ancestral.

What do the root, nodes, branches, and tips represent on a phylogenetic tree?

Root = MRCA of all taxa in the tree Node = divergence point from a common ancestor Branch = connects parts of the tree (may indicate evolutionary distance) Tips/Terminals = descendant taxa at the ends

How do monophyletic, paraphyletic, and polyphyletic groups differ?

Monophyletic (clade) = MRCA + ALL descendants Paraphyletic = MRCA + SOME descendants Polyphyletic = Does not contain the MRCA of all members and often includes organisms with separate evolutionary origins

What are sister groups on a phylogenetic tree?

Sister groups are two taxa or clades that are each other's closest relatives, occurring when one ancestral lineage divides into two daughter lineages.

What is the rule for determining which organisms are most closely related on a phylogenetic tree?

Trace their branches backward until you find their most recent common ancestor (MRCA). Taxa sharing a more recent common ancestor are more closely related. Do NOT judge relatedness based on physical proximity at the tips.

What are the five grades of animal organization in order of increasing complexity?

1. Protoplasmic Grade
2. Cellular Grade
3. Cell-Tissue Grade
4. Tissue-Organ Grade
5. Organ-System Grade

What are the $11$ recognized animal organ systems?

1. Skeletal
2. Muscular
3. Integumentary
4. Digestive
5. Respiratory
6. Circulatory
7. Excretory
8. Nervous
9. Endocrine
10. Immune
11. Reproductive

What are the key differences between spherical, radial, and bilateral symmetry?

Spherical symmetry = any plane passing through the center produces mirrored halves. Radial symmetry = two or more planes through the longitudinal axis produce mirrored halves. Bilateral symmetry = only the sagittal axis divides the organism into mirrored right and left halves.

What do the body direction terms anterior, posterior, dorsal, ventral, medial, lateral, distal, and proximal mean?

Anterior = Head end Posterior = Tail end Dorsal = Back/upper side Ventral = Front/belly side Medial = Toward the body's midline Lateral = Toward the sides Distal = Farther from the middle Proximal = Nearer to the midline

Which body planes divide an animal into Dorsal/Ventral, Right/Left, and Anterior/Posterior regions?

Frontal / Coronal Plane = divides Dorsal $↔$ Ventral Sagittal Plane = divides Right $↔$ Left Transverse Plane / Cross Section = divides Anterior $↔$ Posterior

What are the three embryonic germ layers and what do they give rise to?

Endoderm = forms the gut lining Ectoderm = forms the outer layer of cells Mesoderm = the third germ layer that forms between ectoderm and endoderm in triploblastic organisms

What is the difference between diploblastic and triploblastic animals?

Diploblastic animals have two germ layers (ectoderm and endoderm), whereas triploblastic animals have three germ layers (ectoderm, mesoderm, and endoderm).

How does mesoderm formation differ between protostomes and deuterostomes?

In protostomes, mesoderm forms from endodermal cells near the blastopore (allowing acoelomate, pseudocoelomate, or coelomate plans). In deuterostomes, mesoderm develops from cells in the central region of the gut, creating a coelomic cavity (only coelomate plan is possible).

What defines the acoelomate, pseudocoelomate, and coelomate body cavity arrangements?

Acoelomate = No cavity between gut and body wall (blastocoel filled with parenchyma). Pseudocoelomate = Cavity (persistent blastocoel) only partially surrounded by mesoderm. Coelomate = True coelom completely surrounded by mesoderm and lined with peritoneum.

What is metamerism (segmentation) and what advantages does it provide?

Metamerism is the serial repetition of similar body segments (metameres or somites) along the body's longitudinal axis. It allows for greater body mobility, greater structural complexity, and greater functional complexity.

What are four biological advantages associated with larger body size in animals?

1. Buffers animals against environmental fluctuations
2. Provides greater protection from predators
3. Improves offensive abilities
4. Allows more efficient use of metabolic energy