Animal Taxonomy and Classification

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Questions and Answers

What characterizes animals as a group?

Unicellular and eukaryotic

Multicellular and prokaryotic

Unicellular and prokaryotic

Multicellular and eukaryotic (correct)

Who is known as the father of taxonomy?

Carolus Linnaeus (correct)

Aristotle

Jean-Baptiste Lamarck

Charles Darwin

Which of the following best defines systematics?

Study of biological diversity and evolutionary relationships (correct)

Nomenclature of new species

Classification of extinct organisms

Description of living organisms

What is included in the basis of classification for animals?

Body symmetry Signup and view all the answers

What information can be inferred from the classification hierarchy listing for animals?

Organisms are grouped based on shared characteristics Signup and view all the answers

What is the role of the lateral line system in aquatic vertebrates?

Detecting movement, vibration, and pressure gradients Signup and view all the answers

Which is NOT a criterion for animal classification provided in the content?

Ecosystem role Signup and view all the answers

How does the lateral line system transduce signals into electrical impulses?

Via modified epithelial cells Signup and view all the answers

What type of animals have their cells arranged in two embryonic layers?

Diploblastic animals Signup and view all the answers

Which germ layer is NOT formed by triploblastic animals?

Neoderm Signup and view all the answers

What is the primary difference in body cavity development between diploblastic and triploblastic animals?

Triploblastic animals develop a body cavity called coelom. Signup and view all the answers

Which of the following statements regarding mesoglea is correct?

Mesoglea is a layer found between ectoderm and endoderm in diploblastic animals. Signup and view all the answers

Which animal group does NOT possess true organs?

Cnidaria Signup and view all the answers

What is the composition of tissues formed by the endoderm in triploblastic animals?

Internal organs like lungs and liver Signup and view all the answers

Which axis is not considered one of the three primary body axes?

Body length axis Signup and view all the answers

In which category of animals would you find development of a mesoderm?

Platyhelminthes Signup and view all the answers

Study Notes

Introduction

Animal taxonomy involves identifying, naming, and classifying animals.
Carolus Linnaeus (1707-1778) is recognized as the founder of taxonomy.
There are approximately 1.2 million identified animal species, with estimates of 9-10 million total species on Earth.
The importance of classification lies in assigning a systematic position to newly discovered species.

Taxonomy vs. Systematics

Taxonomy focuses on describing, naming, and classifying organisms.
Systematics studies biological diversity and evolutionary relationships between organisms.
Taxonomic groups are now based on hypotheses about evolutionary relationships derived from systematics.

Classification

The classification of animals is hierarchical, with progressively smaller and more specific groups within each level.
For example, a species of nematode, Caenorhabditis elegans, is classified as follows:
- Kingdom: Animalia
- Phylum: Nematoda
- Class: Chromadorea
- Order: Rhabditida
- Family: Rhabditidae
- Genus: Caenorhabditis
- Species: elegans

Body Symmetry

Body symmetry refers to the balance of an organism's body parts.
Three axes are considered:
- Anterior-posterior (head-tail) axis
- Dorsal-ventral (back-belly) axis
- Left-right axis
Cross sections bisecting the anterior-posterior axis are used to categorize symmetry:
- Bilateral symmetry: A single plane divides the body into two mirror images.
- Radial symmetry: Many planes can divide the body equally.
- Asymmetry: No plane can divide the body into equal halves.

Coelom

A coelom is a body cavity present in most animals, located between the intestinal canal and the body wall.
The presence of body cavities plays a role in classification.

Germ Layers

Germ layers are the primary tissues that form during embryonic development.
Diploblastic animals: Have two embryonic layers:
- External ectoderm
- Internal endoderm
- Mesoglea present between ectoderm and endoderm
Triploblastic animals: Have three embryonic layers:
- External ectoderm
- Middle layer of mesoderm
- Internal endoderm
- Mesoglea is absent. Instead, the mesoderm is present between the endoderm and ectoderm.

Lateral Line System

The lateral line system (LLS) is a sensory organ found in aquatic vertebrates.
It detects movement, vibration, and pressure changes in the surrounding water.
Hair cells, modified epithelial cells, respond to displacement caused by motion and transduce these signals into electrical impulses through excitatory synapses.

Basis of Classification

Several key characteristics are used to classify animals:
- Body symmetry
- Nature of coelom
- Patterns of digestive, circulatory, and reproductive systems
- Arrangement of cells in germ layers

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Description

This quiz explores the fundamentals of animal taxonomy, including its significance, methods of classification, and the distinction between taxonomy and systematics. You will learn about the hierarchical structure of classification as exemplified by various species.