Biol 305_l2_phylogeny Of Metazoa

Phylogenetics primarily focuses on understanding the evolutionary relationships and history of different kinds of animals through the analysis of genetic characteristics and physical traits.

In biology, a 'kind' refers to a phylum which is a taxonomic rank below kingdom and above class. It represents a group of animals that share a common body plan.

The correct answer highlights the main assumption of the Classical approach and lists commonly used features that are analyzed within this approach. The incorrect answers provide alternative assumptions and features that do not align with the Classical approach in evolutionary biology.

The main trends in the Classical approach to metazoan evolution involve an increase in complexity through the addition and elaboration of features, moving from radial to bilateral symmetry, and from acoelomate to coelomate body plans. Additionally, there is a progression from a simple gastric cavity to a through-gut system, and from diploblastic to triploblastic organization. The evolution also includes the development of cell groups into tissues and then organs, as well as the formation of an open body cavity with segmentation.

Incorrect answers were provided as distractors to test understanding of the definitions and examples provided for acoelomate, psuedocoelomate, and coelomate.

The question asks about the evolutionary advance of tissue organization according to the classical approach. The correct answer points to an image which likely shows a visual representation of the evolutionary advancement of tissue organization. The three incorrect answers provide alternative scenarios that do not align with the classical approach or scientific understanding of tissue organization evolution.

The question is asking to categorize various phylum concepts in a phylogenetic tree based on evolutionary relationships. The incorrect answers provided do not align with the specific classifications mentioned in the question, making them inappropriate choices.

The correct phylogenetic sequence is based on the classical phylogeny theory from Halanych 2004, starting from the simplest organisms to the more complex ones.

Porifera are characterized by their cellular grade of construction, meaning they lack true tissues.

The correct criterion for the sister group of bilateria in Coelenterata is diploblastic tissue grade, which refers to having two primary germ layers during embryonic development.

In classical phylogeny, Platyhelminthes are considered as basal bilateria due to their solid body lacking coelom, which is a defining feature in their classification.

In classical phylogeny, Aschelminthes are considered the sister group to Coelomates based on the criterion that they are Pseudocoelomates, meaning their body cavity is not lined with mesoderm. Acoelomates lack a body cavity altogether, Coelomates have a true body cavity lined with mesoderm, and Protostomes develop their mouth first from the blastopore.

The correct answer focuses on specific biological features related to embryonic development and body cavity formation, which are key criteria for determining the classification of coelomates into Protostomes and Deuterostomes. The incorrect answers provide irrelevant or unrelated criteria that do not contribute to the differentiation of these phylogenetic groups.

In classical phylogeny, one of the main features used to categorize organisms into different groups is the blastopore fate. This refers to whether the blastopore, which is the opening of the central cavity of an embryo in the early stage of development, ultimately becomes the mouth or the anus in the fully developed organism. Deuterostomes-Echinoderms and lophophorates being deuterostomes indicates that their blastopore fate is to become the anus.

In classical phylogeny, the main criterion for the clade Articulata, comprising both Annelida and Athropoda, is segmentation. This refers to the division of the body into repeating segments, a characteristic shared by members of this clade.

The molecular approach to phylogeny focuses on DNA sequences, not morphological, behavioral, or geographical traits.

The correct order is based on the current understanding of the relationships between different taxonomic groups in modern phylogenetics. It is important to consider evolutionary relationships and classification when arranging these groups.

The correct order of the groups in Halanych's modern phylogeny as per the image provided is Arthropoda, Annelida, Chordata, Choanoflagellata, Cnidaria, Echinodermata, Nematoda, Mollusca, Platyhelminthes, Porifera.

Apomorphy refers to a specific concept related to evolutionary traits and character states, distinct from the other incorrect options provided.

Plesiomorphy refers to an ancestral character state that forms the basis for evolutionary novelties. It is not a trait with no evolutionary significance, not necessarily a trait that increases survival chances, and not unique to a particular species.

A symplesiomorphy is a shared ancestral character state, not a unique derived trait, not a trait found in only one descendant group, and not acquired during an organism's lifetime.

A synapomorphy is a specific type of trait that indicates shared ancestry among different groups of organisms, and is not unique to just one group. It is also not a trait that has evolved independently, nor is it a characteristic common to all living organisms.

Monophyletic refers to a group of organisms that captures the most recent common ancestor and all of its descendents, distinguishing it from paraphyletic or polyphyletic groups.

The correct definition of paraphyletic is a group of organisms that includes their most recent common ancestor and some but not all of its descendents. It is important to differentiate between monophyletic, paraphyletic, and polyphyletic groups in understanding evolutionary relationships.

The term 'polyphyletic' specifically refers to a group of organisms that does not include their most recent common ancestor, making it distinct from monophyletic and paraphyletic groups.

In evolutionary biology, a polytomy refers to a branch point on a tree that has more than two immediate descendents. It could represent a lack of knowledge or rapid speciation.