Human Anatomy & Physiology (11th Edition)
11th Edition
ISBN:9780134580999
Author:Elaine N. Marieb, Katja N. Hoehn
Publisher:Elaine N. Marieb, Katja N. Hoehn
Chapter1: The Human Body: An Orientation
Section: Chapter Questions
Problem 1RQ: The correct sequence of levels forming the structural hierarchy is A. (a) organ, organ system,...
Related questions
Concept explainers
Animal Diversity
Nematodes are commonly known as roundworms. They are free-living, very tiny organisms. They have an elongated and tubular body. These organisms have a nervous system and are mostly act as parasites to both animals and plants.
Platyhelminthes
Platyhelminthes are also known as "flatworms" because as they are dorsoventrally flattened from head to tail. They are invertebrate, soft-bodied, acoelomate, unsegmented and have bilateral symmetry.
Question
In both trees, circle the latest common ancestor of Demospongea and Calcarea.
Transcribed Image Text:**Title: Phylogenetic Hypotheses of Porifera**
The image presents two phylogenetic trees illustrating different hypotheses about the evolutionary relationships of the Porifera, commonly known as sponges.
**Hypothesis 1: Porifera is a Monophyletic Group**
- **Monophyletic Group**: In this hypothesis, Porifera is depicted as a single clade, indicating that it forms a distinct, complete lineage branching from a common ancestor.
- **Diagram Structure**:
- **Porifera** branches into several subgroups including:
- **Hexactinellida**: One branch represents the glass sponges.
- **Desmospongiae**: Another branch for the largest class of sponges.
- **Calcarera**: A separate branch for calcareous sponges.
- **Eumetazoa**: Also branches from the main Porifera clade, signifying the divergence of true multicellular organisms.
**Hypothesis 2: Porifera is a Paraphyletic Group**
- **Paraphyletic Group**: In this scenario, Porifera is not a single lineage. Instead, it is a paraphyletic group, meaning it includes some, but not all, descendants of a common ancestor.
- **Diagram Structure**:
- The tree begins with **Hexactinellida**, branching separately from other groups.
- **Calcarera** splits off next, followed by **Eumetazoa** and a final branch for **Desmos.** (Desmospongiae).
**Comparison and Analysis**:
- **Monophyletic vs. Paraphyletic**: The key distinction between these hypotheses lies in whether Porifera itself is considered a complete, cohesive evolutionary group or a collection of lineages not inclusive of all descendants from their last common ancestor.
- **Significance**: Understanding these differences helps scientists study evolutionary biology, diversity, and the historical classification of sponges in relation to other multicellular organisms.
These hypotheses continue to be subjects of research and debate, illustrating varying evolutionary interpretations of the Porifera lineage.
Expert Solution
Step 1
Ancestors
The species which share common charector of two different species or ancestors are the species from which two or more than two new species originate.
Step by step
Solved in 2 steps with 1 images
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, biology and related others by exploring similar questions and additional content below.Recommended textbooks for you
Human Anatomy & Physiology (11th Edition)
Biology
ISBN:
9780134580999
Author:
Elaine N. Marieb, Katja N. Hoehn
Publisher:
PEARSON
Biology 2e
Biology
ISBN:
9781947172517
Author:
Matthew Douglas, Jung Choi, Mary Ann Clark
Publisher:
OpenStax
Anatomy & Physiology
Biology
ISBN:
9781259398629
Author:
McKinley, Michael P., O'loughlin, Valerie Dean, Bidle, Theresa Stouter
Publisher:
Mcgraw Hill Education,
Human Anatomy & Physiology (11th Edition)
Biology
ISBN:
9780134580999
Author:
Elaine N. Marieb, Katja N. Hoehn
Publisher:
PEARSON
Biology 2e
Biology
ISBN:
9781947172517
Author:
Matthew Douglas, Jung Choi, Mary Ann Clark
Publisher:
OpenStax
Anatomy & Physiology
Biology
ISBN:
9781259398629
Author:
McKinley, Michael P., O'loughlin, Valerie Dean, Bidle, Theresa Stouter
Publisher:
Mcgraw Hill Education,
Molecular Biology of the Cell (Sixth Edition)
Biology
ISBN:
9780815344322
Author:
Bruce Alberts, Alexander D. Johnson, Julian Lewis, David Morgan, Martin Raff, Keith Roberts, Peter Walter
Publisher:
W. W. Norton & Company
Laboratory Manual For Human Anatomy & Physiology
Biology
ISBN:
9781260159363
Author:
Martin, Terry R., Prentice-craver, Cynthia
Publisher:
McGraw-Hill Publishing Co.
Inquiry Into Life (16th Edition)
Biology
ISBN:
9781260231700
Author:
Sylvia S. Mader, Michael Windelspecht
Publisher:
McGraw Hill Education