Evolutionary Biology Key Terms

Questions and Answers

What term describes a change occurring within a lineage?

Cladogenesis

Homology

Anagenesis (correct)

Clade

Which option best describes an apomorphy?

A shared trait among multiple descendants

A primitive character state

A derived or specialized character (correct)

A characteristic serving no evolutionary purpose

What is the purpose of bootstrapping in phylogenetic analysis?

To identify the ancestral state of a clade

To create a complete phylogenetic tree

To evaluate the reliability of a branching pattern (correct)

To determine the evolutionary age of a lineage

Which of the following best describes a clade?

A group including an ancestor and all its descendants Signup and view all the answers

What is an autapomorphy?

A derived character unique to one descendant Signup and view all the answers

Which concept refers to the independent acquisition of similar characteristics from different ancestors?

Homoplasy Signup and view all the answers

What do homologous characters indicate about species?

They share a common ancestor. Signup and view all the answers

Which statement is true regarding derived states?

They represent a modification from the original state. Signup and view all the answers

What is the maximum size of placozoans observed in laboratory culture?

2 mm Signup and view all the answers

Which characteristic is NOT true about placozoans?

They have a basal lamina. Signup and view all the answers

What distinguishes the ventral layer of placozoans?

It has a single flagellum on each columnar cell. Signup and view all the answers

What type of digestion do placozoans utilize?

Extracellular digestion Signup and view all the answers

Which method of reproduction is observed in placozoans?

Both asexual and sexual reproduction Signup and view all the answers

Which aspect of placozoans' cellular structure is unique compared to sponges?

Presence of fibrous cells Signup and view all the answers

Genetic evidence places placozoans at which position in the metazoan lineage?

At the very root of the metazoan tree Signup and view all the answers

What is a notable feature observed in the upper layer of placozoans?

It has numerous shiny spheres for chemical defense. Signup and view all the answers

Which phylum includes a highly diverse group of parasites largely restricted to invertebrate hosts?

Phylum Apicomplexa Signup and view all the answers

What is unique about the mitochondrial cristae in the Rhizaria group?

They are tubular like many other eukaryotes. Signup and view all the answers

Which of the following is NOT a feature of foraminiferans?

They exclusively inhabit terrestrial environments. Signup and view all the answers

Which phylum is characterized by organisms possessing radiating microtubular supports known as axopodia?

Phylum Radiolaria Signup and view all the answers

What role do foraminiferans play in marine sediment?

They contribute to the formation of Globigerina ooze. Signup and view all the answers

Which dinoflagellate is recognized for its potential to produce harmful algal blooms?

Alexandrium Signup and view all the answers

Which statement about the ciliates is accurate?

They consist of about 3,500 described species. Signup and view all the answers

How can the species composition of foraminiferan fossils be utilized?

To date ancient sediments. Signup and view all the answers

What primarily differentiates the placozoan mitochondrial genome from other animal genomes?

It contains numerous intragenic spacers and introns. Signup and view all the answers

Which of the following locomotion methods is NOT characteristic of protozoans?

Waving movement Signup and view all the answers

Which reproductive method involves the exchange of genetic material between two organisms?

Conjugation Signup and view all the answers

What is the primary mode of nutrition for parasitic protozoans?

Absorption Signup and view all the answers

What aspect of placozoan evolution suggests they may be simplified from a more complex ancestor?

Loss of the nervous system Signup and view all the answers

Which of the following is NOT a characteristic of eukaryotic protists?

Predominantly multicellular Signup and view all the answers

What is the primary method of reproduction for most Foraminifera?

Asexual through binary fission Signup and view all the answers

Which group of protists uses pseudopodia for movement and feeding?

Amoeboid protozoans Signup and view all the answers

What role do transcription factors and signaling genes play in the placozoan genome?

Involved in embryonic development Signup and view all the answers

Which characteristic is specific to Rhizaria?

Possess complex, often mineralized shells Signup and view all the answers

Which of the following statements is true about phytoflagellates?

They are primarily autotrophic and photosynthetic. Signup and view all the answers

What defines a eukaryotic organism?

Has a membrane-bound nucleus and organelles Signup and view all the answers

Which of the following is NOT a function of pseudopodia?

Cell division Signup and view all the answers

What is the function of choanocytes in sponges?

Driving water flow and capturing food particles Signup and view all the answers

Which group of protozoans is known to have a symbiotic lifestyle?

Zooflagellates Signup and view all the answers

What is the primary nutrition mode of zooflagellates?

Heterotrophic Signup and view all the answers

Study Notes

Key Terms in Evolutionary Biology

Anagenesis: Change that occurs within a single lineage over time.
Ancestral (Primitive) State: The original character state from which current members of a clade have evolved; also known as the plesiomorphic state.
Apomorphy: A derived or specialized character that distinguishes a species.
Autapomorphy: A unique derived character found in only one descendant of an ancestor, limiting its utility for inferring relationships.
Bayesian Inference: A statistical method to assess the likelihood of a phylogenetic hypothesis being correct.
Bootstrapping: A resampling technique used to test the reliability of phylogenetic tree branches, often involving 500-1,000 simulations to calculate bootstrap values.

Cladistics and Taxonomy

Clade: A group of organisms that includes a common ancestor and all its descendants, defining a monophyletic group.
Cladogenesis: The process by which a single lineage branches into two or more distinct lineages.
Cladogram: A visual representation of branching sequences in evolution based on morphological or molecular changes.
Derived State: A character that has been modified from its ancestral condition; referred to as the apomorphic state.

Evolutionary Relationships

Homologous Characters: Features derived from a common ancestor, used to determine evolutionary relationships among species; basis of homology.
Homoplasy: The independent evolution of similar traits in different lineages, leading to false similarities in homology.

Protist Diversity

Eukaryotic Organisms: Unicellular organisms, including a diverse array of autotrophic and heterotrophic types, classified under various phyla.

Major Groups of Protists

Amoeboid Protozoans: Use pseudopodia for movement and feeding; include free-living and shell-bearing species.
Rhizaria: Characterized by filamentous pseudopodia; include Radiolarians and Foraminifera, mostly found in marine environments.
Flagellated Protozoans: Divided into phytoflagellates (autotrophic) and zooflagellates (heterotrophic), with diverse habitats and reproductive strategies.

Locomotion and Reproduction in Protozoans

Flagella: Long, whip-like structures for swimming; common in flagellates.
Cilia: Short, hair-like appendages that beat in unison for movement; prevalent in ciliates.
Pseudopodia: Temporary extensions for movement and feeding, primarily used by amoeboid protozoans.
Asexual Reproduction: Common methods include binary fission and budding; sexual reproduction occurs via conjugation in ciliates.

Phylum Characteristics

Porifera (Sponges): Simplest multicellular animals; lack true tissues; primarily marine; filter-feeding through water circulation facilitated by specialized cells like choanocytes.

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Description

Test your understanding of key concepts in evolutionary biology such as anagenesis, ancestral state, and apomorphy. This quiz covers fundamental definitions that are critical in studying the evolution of species and their relationships. Perfect for students or enthusiasts looking to deepen their knowledge in this field.