Systematics & Taxonomy Chapter 2

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Questions and Answers

Which characteristic is true for Eukarya that possess a cell wall?

It contains peptidoglycan.

It is composed of cellulose.

It does not contain peptidoglycan. (correct)

It primarily functions for photosynthesis.

What is a defining feature of the Plantae kingdom?

Organisms obtain nutrients through absorption.

Cells lack cell walls.

Organisms are primarily unicellular.

Cells are organized into tissues and carry out photosynthesis. (correct)

What form of genetic material is unique to the Eukarya?

Chloroplast DNA.

Prokaryotic ribosomal RNA.

Distinct mitochondrial DNA.

Unique rRNA sequences. (correct)

Which of the following is NOT a characteristic of the Fungi kingdom?

They undergo photosynthesis for nutrient acquisition. Signup and view all the answers

How do organisms in the Animalia kingdom primarily obtain their nutrients?

Through ingestion. Signup and view all the answers

What is the main focus of systematics?

Study of diversification and relationships of life forms Signup and view all the answers

Which of the following is NOT a stage in taxonomy?

Delta taxonomy Signup and view all the answers

Who defined systematics as the 'scientific study of the kinds and diversity of organisms'?

George Gaylord Simpson Signup and view all the answers

What does phylogenetics study?

The evolutionary relationships among organisms Signup and view all the answers

In which stage of taxonomy are species identified and characterized based on gross morphological features?

Alpha taxonomy Signup and view all the answers

Which term refers to the practice of naming, describing, and identifying organisms?

Taxonomy Signup and view all the answers

What do tree-like diagrams in phylogenetics represent?

Hypotheses of evolutionary relationships Signup and view all the answers

Which prominent figure is recognized for sketching one of the earliest known phylogenetic trees?

Charles Darwin Signup and view all the answers

What is the main characteristic that distinguishes Bacteria from Archaea?

Bacteria contain peptidoglycan in their cell walls. Signup and view all the answers

Which statement correctly describes the rRNA of Bacteria?

It is unique and distinct from both Archaea and Eukarya. Signup and view all the answers

What is a characteristic feature of Archaea cell membranes?

They have branched hydrocarbon chains. Signup and view all the answers

How are Bacteria and Eukarya similar regarding their cell membranes?

Both use ester linkages in their membranes. Signup and view all the answers

What term refers to the evolutionary relationships between organisms?

Phylogeny Signup and view all the answers

Which of the following antibiotics are Bacteria sensitive to?

Traditional antibacterial antibiotics. Signup and view all the answers

What do nodes represent in a phylogenetic tree?

Common ancestors shared by terminal taxa Signup and view all the answers

Which characteristic does NOT belong to Archaea?

They are sensitive to antibiotics affecting Bacteria. Signup and view all the answers

Which of the following is NOT an important requisite of taxa names?

Flexibility Signup and view all the answers

Which statement is true regarding the relationship between systematics and taxonomy?

Systematics is not subject to change over time. Signup and view all the answers

What is the primary focus of taxonomy?

Classification and identification of species Signup and view all the answers

What did Linnaeus contribute to biological classification?

The binomial nomenclature system for naming organisms Signup and view all the answers

How does the depth of a node in a phylogenetic tree relate to the relationship between terminal taxa?

Deeper nodes indicate distantly related taxa. Signup and view all the answers

What is a defining feature of Eukarya compared to Archaea and Bacteria?

Eukarya have eukaryotic cells. Signup and view all the answers

What does the International Code of Zoological Nomenclature regulate?

Rules for animal naming and nomenclature problems Signup and view all the answers

In the context of nomenclature, what does 'stability' refer to?

Names should remain unchanged over time Signup and view all the answers

Study Notes

Systematics

Systematics studies the diversification and relationships of both extinct and extant life forms.
The term derives from 'systema', linked to Linnaeus's 1735 classification work "Systema Naturae."
Modern systematics incorporates molecular biology and computational tools.

Definition and Components

George Gaylord Simpson defines systematics as a scientific study of organism diversity and relationships, focusing on biodiversity.
Two major components of systematics are:
- Taxonomy
- Phylogenetics

Taxonomy

Taxonomy comes from Greek, meaning "arrangement" and "law."
It involves classifying organisms into taxa and governs naming, describing, and preserving specimens.
Developed significantly by Carl Linnaeus in the 18th century for both living and extinct organisms.
Classification relies on three stages:
- Alpha taxonomy focuses on identifying species through morphological features.
- Beta taxonomy arranges species hierarchically from lower to higher categories.
- Gamma taxonomy studies intraspecific differences and evolutionary history.

Phylogenetics

Phylogenetics examines evolutionary relationships among organisms, often depicted using tree diagrams.
Charles Darwin illustrated early phylogenetic trees in 1837 and in "On the Origin of Species" (1859).
Tree components include:
- Terminal taxa connected by branches.
- Branching points (nodes) represent common ancestors.
Relationships are indicated by node depth; closer relatives share shallower nodes.

Taxonomy vs. Systematics

Taxonomy is a crucial subset of systematics, encompassing naming and describing species.
Systematics provides a broader framework for all taxonomic functions and includes evolutionary history.
Systematics interacts directly with environmental factors, unlike taxonomy, which relates indirectly.
Taxonomic classifications may evolve over time, but well-established systematics remain stable.

Nomenclature

Nomenclature, derived from Latin, involves naming taxa to improve communication among biologists.
Binomial nomenclature, established by Linnaeus in 1758, includes a genus and species name for each organism.

Taxon Name Characteristics

Unique: Each name must be distinct.
Universal: Names should be recognized globally.
Stable: Names should remain unchanged over time.
The International Code of Zoological Nomenclature guides animal naming and nomenclature issues.

Types of Nomenclature

Binomial nomenclature involves two names.
Trinomial nomenclature identifies subspecies (e.g., Indian Lion – Panthera leo persica).

The Three Domains of Life

The Three Domain System by Carl Woese classifies life based on ribosomal RNA sequences and membrane lipid structures.
Domains are:
- Bacteria
- Archaea
- Eukarya

Bacteria

Prokaryotic cells, prevalent in daily life.
Includes mycoplasmas, cyanobacteria, Gram-positive, and Gram-negative bacteria.
Unique characteristics include:
- Cell walls containing peptidoglycan.
- Sensitivity to traditional antibacterial antibiotics.

Archaea

Also prokaryotic, but have distinct features compared to Bacteria:
- Membranes composed of branched hydrocarbon chains.
- Lack peptidoglycan in cell walls.
- Varied antibiotic sensitivity.

Eukarya

Consists of eukaryotic cells with varying characteristics:
- Membranes similar to Bacteria, with unique rRNA.
- Not all Eukarya have cell walls, and those that do lack peptidoglycan.
- Eukarya are organized into four kingdoms:
  - Protista: Mostly unicellular eukaryotes like slime molds and algae.
  - Fungi: Unicellular or multicellular organisms with cell walls and absorptive nutrient acquisition, including molds and yeasts.
  - Plantae: Multicellular organisms that photosynthesize, including mosses and flowering plants.
  - Animalia: Multicellular, tissue-organized organisms that ingest nutrients, including sponges and vertebrates.

Conclusion

Understanding systematics and taxonomy is essential for studying biodiversity and the evolutionary relationships among organisms.

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Description

Dive into Chapter 2 of Systematics and Taxonomy, which explores the study of biodiversity and the classification of life forms. This chapter discusses the historical context of systematics, including Linnaeus's contribution to classification. Gain insights into both extinct and extant species and their evolutionary relationships.