Introduction to Systematics

Flashcards based on key vocabulary and concepts from the lecture on Systematics.

Systematics

The science that includes traditional taxonomy, the description, nomenclature, and classification of organisms, aiming to reconstruct evolutionary history.

Phylogeny

The evolutionary history and relationships among species.

Taxonomy

A branch of systematic biology that identifies, names, and organizes biodiversity into related categories.

Binomial Nomenclature

A two-part Latin naming system for organisms, established by Carolus Linnaeus, consisting of the genus and specific epithet.

Hierarchical Classification

The grouping of organisms into ranked categories such as Domain, Kingdom, Phylum, etc.

Morphological Characteristics

Physical traits used to describe and classify organisms.

Cladistics

A classification method that groups organisms based on shared common ancestors.

Homology

Traits in two or more taxa inherited from a common ancestor, resulting in structural similarity.

Analogy

Traits that have similar functions in different species but do not arise from a common ancestor.

Monophyletic Group

A group of taxa where each taxon is more related to each other than to any outside taxa.

Paraphyletic Group

A group that includes a common ancestor but not all its descendants.

Polyphyletic Group

A group that does not include the most recent common ancestor of all members.

Character States

Different forms or variations of a character used in the classification of organisms.

Reproductive Isolation

Biological factors that prevent members of two species from interbreeding and producing fertile offspring.

Prezygotic Barriers

Factors that prevent fertilization from occurring between species.

Postzygotic Barriers

Factors that prevent a hybrid zygote from developing into a viable, fertile adult.

Allopatric Speciation

The formation of new species due to geographical isolation.

Sympatric Speciation

The evolution of new species from a single ancestral species while inhabiting the same geographic region.

Phylogenetic Tree

A branching diagram that illustrates evolutionary relationships among species.

Eukarya

One of the three domains that contain organisms with complex cells, including plants, animals, fungi, and protists.

Prokaryotes

Single-celled organisms that lack a nucleus; includes domains Archaea and Bacteria.

Coelomate

Organisms that possess a true body cavity lined with mesoderm.

Pseudocoelomate

Organisms with a body cavity partially lined with mesoderm.

Acoelomate

Organisms that lack a body cavity between the gut and body wall.

Evolutionary Taxonomy

Taxonomy system that retains aspects of Linnaean taxonomy but emphasizes evolutionary relationships.

Convergent Evolution

The independent evolution of similar features in different lineages due to similar environmental pressures.

Dichotomous Key

A tool that allows the identification of organisms using a series of choices that lead to the correct name.

Ecology

The study of how organisms interact with their environment.

Speciation

The process through which new species arise.

Transitional Fossils

Fossils that exhibit traits common to both an ancestral group and its derived descendant group.

Macroevolution

Evolutionary changes that occur at or above the level of species.

Microevolution

Small-scale evolutionary changes, typically observed over shorter time spans.

What are major animal phyla?

Major animal phyla are the primary groups of animals categorized based on shared characteristics and evolutionary relationships.

What is the Phylum Porifera?

Phylum Porifera consists of sponges, which are simple animals characterized by a porous body and lack of true tissues.

What does Phylum Cnidaria include?

Phylum Cnidaria includes jellyfish, corals, and sea anemones, known for their stinging cells called cnidocytes.

What is a key characteristic of Phylum Mollusca?

Phylum Mollusca includes animals such as snails and octopuses, characterized by a soft body, often protected by a hard shell.

What defines Phylum Arthropoda?

Phylum Arthropoda includes insects, arachnids, and crustaceans, defined by having an exoskeleton, segmented body, and jointed appendages.

What is unique about Phylum Chordata?

Phylum Chordata includes animals with a notochord, a dorsal hollow nerve cord, pharyngeal slits, and a post-anal tail.

What is the Phylum Echinodermata?

Phylum Echinodermata includes marine animals such as starfish and sea urchins, characterized by radial symmetry and a water vascular system.

What distinguishes Phylum Annelida?

Phylum Annelida includes segmented worms like earthworms and leeches, characterized by their segmented bodies and a true coelom.

What are the key features of Phylum Nematoda?

Phylum Nematoda includes roundworms, characterized by their unsegmented bodies and a tough outer cuticle.

What is a common example of Phylum Platyhelminthes?

Phylum Platyhelminthes includes flatworms, such as planarians and tapeworms, known for their flat bodies and bilateral symmetry.

What defines Phylum Rotifera?

Phylum Rotifera includes microscopic animals called rotifers, known for their ciliated corona and ability to survive extreme conditions.

What does a phylogenetic tree of animals represent?

A phylogenetic tree of animals represents the evolutionary relationships among different animal species, illustrating how they are related through common ancestors.

What is the significance of branching in a phylogenetic tree?

The branching in a phylogenetic tree indicates the divergence of species from common ancestors, showing evolutionary pathways and relationships among groups.

What are nodes in the context of a phylogenetic tree?

Nodes in a phylogenetic tree represent points of divergence, where an ancestral species splits into two or more descendant species.

What does a clade indicate in a phylogenetic tree?

A clade in a phylogenetic tree indicates a group of organisms that includes a common ancestor and all its descendants, reflecting evolutionary lineage.

How is morphological data used in constructing a phylogenetic tree of animals?

Morphological data, such as physical traits and structures, is used to identify similarities and differences that help determine evolutionary relationships in a phylogenetic tree.