Classification of Living Organisms

These flashcards summarize key concepts from the lecture on the classification of living organisms, focusing on the systems of classification, evolutionary theories, and the methods used in taxonomy.

What process occurs as life on Earth changes over time?

Evolution.

What did Charles Darwin's theory of evolution emphasize about offspring?

Organisms produce more offspring than can survive.

What is 'taxonomy'?

The branch of biology that classifies organisms and assigns each a universally accepted name.

What is 'binomial nomenclature'?

A naming system with two parts used to assign scientific names.

What is the biggest classification group in Linnaeus’s system?

Kingdom.

What is the highest level of classification recently added above kingdoms?

Domain.

According to Linnaeus's system, what are the seven levels of classification?

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

What must organisms in the same species be able to do?

Mate and produce fertile offspring.

What is a phylogenetic tree?

A family tree showing the evolutionary relationships among groups of organisms.

Define homologous structures.

Structures in different species that are similar due to common ancestry.

What are analogous structures?

Structures that are similar in function but not in structure, not derived from a common ancestor.

What are vestigial structures?

Structures that are reduced in size and seem to be left over from a previous ancestor.

What does morphology refer to?

The structure and form of organisms.

What are biochemical similarities used for in classification?

To show relationships between organisms based on chemical compounds and proteins.

How do genetic similarities help understand relationships between organisms?

Same genes or similar DNA can indicate a common ancestry.

What does embryological similarity provide evidence of?

Phylogenetic relationships among different species.

What are shared derived characters?

Features shared by a group of organisms that provide evidence of common ancestry.

What is a clade?

A group of organisms that includes an ancestor and all its descendants.

What is a cladogram?

A diagram that shows evolutionary relationships among organisms.

What structures compose the cell walls in Eubacteria?

Peptidoglycans.

What kingdom do Methanogens and Thermophiles belong to?

Kingdom Archaebacteria.

What are the four kingdoms found in the domain Eukarya?

Protista, Plantae, Fungi, and Animalia.

What is an example of a heterotroph in the Kingdom Fungi?

Mushrooms.

What type of cell structure do plants possess?

Cell walls made of cellulose.

What is a physical barrier that can keep species apart?

Mating is impossible under natural conditions.

What are behavioral barriers in species classification?

Certain behaviors must be exhibited for mating.

What do scientists use to classify organisms?

A dichotomous key.

What does the phylogeny of an organism represent?

Its evolutionary history.

Why is it important not to use common names for organisms?

Common names can be confusing and misleading.

What is one key rule in binomial nomenclature regarding scientific names?

The genus name is capitalized and the species name is not.

What characterizes species in the same genus?

They share closely related traits.

Why do scientists classify fungi separately from plants?

Fungi have cell walls made of chitin and do not have chloroplasts.

How can genetic similarities explain unexpected relationships?

Different-looking organisms might have similar genes, revealing a common ancestry.

What evolutionary evidence can fossils provide?

Fossils show that present organisms are similar to extinct ones.

How does the classification of organisms continually evolve?

As new discoveries and technologies emerge.