Biology 9: Classification Systems

Questions and Answers

Give two reasons for having a biological classification system.

1 - For accurate communication between scientists; 2 - It organizes organisms and allows them to be studied in an organized fashion.

Why are Aristotle's and Linnaeus's groupings of living things considered artificial classification systems?

Because they are based on primarily observable characteristics.

List from largest to smallest the seven basic levels in the modern classification hierarchy.

Kingdom, Phylum, Class, Order, Family, Genus, Species.

Describe three general rules for using the modern biological classification system.

1 Each group on one level of the hierarchy may be divided into several groups on the next lower level; 2. Each group has various characteristics that all levels under the group possess; 3. Each level of the hierarchy can be divided into smaller units before reaching the next lower level. Signup and view all the answers

List the six kingdoms of living things and give characteristics of each.

1- Archaebacteria - prokaryotic, unicellular/microscopic, no peptidoglycan in cell walls; 2- Eubacteria - prokaryotic, contain peptidoglycan, unicellular; 3- Protista - autotrophic or heterotrophic, mobile or sessile, unicellular or colonial; 4 - Fungi - all heterotrophic, unicellular or colonial; 5 - Plantae - autotrophic, sessile as adults, formation of tissues; 6- Animalia - heterotrophic, tissue formation, most motile. Signup and view all the answers

What is a domain?

A domain is larger than a kingdom - there are three domains - Archae, Bacteria, and Eukarya. Signup and view all the answers

Give two reasons for having a system of scientific names.

<ol> <li>A common name applies to several different organisms; 2. Confusion if everything has the same common name.</li> </ol> Signup and view all the answers

What are two reasons for using Latin to name organisms?

1- Latin does not change since it is a dead language; 2- Most scientists at the time knew Latin and it is a very descriptive language. Signup and view all the answers

What is the primary division of a species?

Varieties Signup and view all the answers

What is the difference between classifying and identifying an organism?

When scientists identify an organism, they determine to which taxonomic groups it belongs; to classify an organism, a scientist examines it closely and assigns it to a particular group based on characteristics. Signup and view all the answers

What is a dichotomous key?

A series of paired statements or characteristics about the specimen being identified. Signup and view all the answers

Give two commonly accepted parts of the definition of a species.

<ol> <li>Members of a species are structurally similar but do have a degree of variation; 2. Members of a species can interbreed and produce viable and fertile offspring under natural conditions.</li> </ol> Signup and view all the answers

Why are physical characteristics an inadequate basis for grouping members of a species?

An organism's environment can greatly affect its appearance, leading to errors in classification based on physical traits. Signup and view all the answers

List and describe three factors that may lead to speciation.

<ol> <li>Migration - the movement of organisms can lead to separation of traits; 2. Isolation - mechanisms causing groups to be called separate species; 3. Adaptation - inheritable characteristics providing survival advantages.</li> </ol> Signup and view all the answers

Explain how migration, isolation, and adaptation might account for various groups of animals coming into existence after the flood.

As animals on Noah's ark were dispersed, the variability in their gene pool allowed them to interact with the environment. Signup and view all the answers

What is the primary characteristic that would place an organism into a biblical kind?

The ability to reproduce. Signup and view all the answers

Compare evolutionary and an artificial system of classification of living things.

The Evolutionary Classification System is based on biochemical and genetic relationships rather than superficial traits. Signup and view all the answers

Study Notes

Biological Classification System

Promotes accurate communication among scientists.
Organizes organisms for systematic study.

Artificial Classification Systems

Aristotle's and Linnaeus's systems rely on observable characteristics.
Groupings are primarily based on appearance rather than genetic relationships.

Modern Classification Hierarchy

Seven levels: Kingdom, Phylum, Class, Order, Family, Genus, Species.

Rules for Using Biological Classification

Each hierarchical group can be subdivided into smaller groups.
Groups share common characteristics that descend through levels.
Each level can be further divided before transitioning to the next level.

Six Kingdoms of Living Things

Archaebacteria: Prokaryotic, unicellular, lacks peptidoglycan in cell walls.
Eubacteria: Prokaryotic, contains peptidoglycan, unicellular.
Protista: Autotrophic or heterotrophic, can be mobile or sessile, unicellular or colonial.
Fungi: Heterotrophic, unicellular or colonial.
Plantae: Autotrophic, sessile in adulthood, forms tissues.
Animalia: Heterotrophic, tissue formation, primarily motile.

Domain Classification

Three domains: Archae, Bacteria, and Eukarya.
Based on biochemical characteristics of organisms.

Importance of Scientific Naming System

Common names may refer to multiple organisms, causing confusion.
Ensures clarity when communicating about different species.

Use of Latin in Scientific Naming

Latin remains unchanged, providing consistency in naming.
Widely known among scientists and highly descriptive.

Species Definition

Primary division of a species is into varieties.
Members possess structural similarities with inherent variations.
Members can interbreed and produce viable, fertile offspring naturally.

Classifying vs. Identifying Organisms

Identification involves determining taxonomic classification (genus and species).
Classification involves examination and assignment based on characteristics.

Dichotomous Key

A tool consisting of paired statements for identifying specimens.
Only one statement from each pair can be true.

Limitations of Physical Characteristics

Environmental influences can distort appearance and mislead classification.
Physical traits alone may not accurately represent genetic relationships.

Factors Leading to Speciation

Migration can separate organism groups enough to create distinct species.
Isolation mechanisms can result in the development of unique species.
Adaptation refers to inheritable traits that enhance survival.

Post-Flood Animal Diversity

Dispersal from Noah's Ark, combined with genetic variability, leads to new species.
Variations can arise quickly, observable within 5 to 10 generations, challenging evolutionary explanations.

Biblical Kind Definition

The primary characteristic of a biblical kind is the ability to reproduce.

Evolutionary Classification vs. Artificial Systems

Evolutionary classification relies on biochemical and genetic relationships, contrasting with visually based artificial classifications.

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Description

Explore the importance of biological classification systems through flashcards. Learn why accurate communication and organization of organisms are vital in biological studies, as well as the limitations of Aristotle's and Linnaeus's classifications.