36 Questions
What is the likely outcome of the origin of Ubx and abd-A Hox genes in the arthropod body plan?
Increased complexity of body segments
Which group of invertebrates was used to test the hypothesis about the origin of Ubx and abd-A Hox genes?
Onychophorans
What is the difference between arthropods and onychophorans in terms of body segment diversity?
Arthropods have diverse body segments, while onychophorans have identical body segments
What is the function of Ubx and abd-A Hox genes in arthropods?
Influence segmentation
What is the likely ancestral relationship between onychophorans and arthropods?
Onychophorans and arthropods share a common ancestor
What is the significance of studying the evolutionary history of arthropods?
To understand the diversity of species on Earth
What is the primary driver of body segment diversity in arthropods?
Changes in the sequence or regulation of existing Hox genes
What is the significance of studying Hox genes in onychophorans?
To test whether arthropod body plan diversity arose from new Hox genes
What is a characteristic feature of modified appendages in arthropods?
They are paired and jointed
What did Carroll and colleagues find in their study of Hox genes in the onychophoran Acanthokara kaputensis?
The presence of all arthropod Hox genes, including Ubx and abd-A
What is a possible outcome of changes in the sequence or regulation of developmental genes such as Hox genes?
Changes in form and body plan
What is a close relative of arthropods that was studied to understand the evolution of body segment diversity?
Onychophorans
What is the significance of the fossil record of the Cambrian explosion in understanding arthropod evolution?
It reveals the gradual evolution of arthropods from lobopod ancestors.
What is a key feature of early arthropods such as trilobites?
They showed little variation from segment to segment.
What is the likely reason for the great diversification of arthropods?
The evolution of specialized appendages for different functions.
What is the significance of the extinction event 250 million years ago?
It led to the extinction of all trilobite species.
What is a characteristic of lobopods, which are thought to be the ancestors of arthropods?
Most of their body segments were identical to one another.
What is a key innovation that contributed to the success of arthropods?
Their segmented body plan and jointed appendages.
What is a fundamental feature of animal body plans that helps explain why most animals are not a hollow ball of cells?
Gastrulation
What is the main difference between radial symmetry and bilateral symmetry in animals?
Radial symmetry has no front and back ends, while bilateral symmetry has two axes of orientation
What is a characteristic feature of sponges that distinguishes them from other animals?
They lack symmetry altogether
What is the likely outcome of changes in the molecular control of gastrulation over millions of years?
It would remain unchanged for millions of years
What is the significance of studying animal body plans in the context of evolution?
It reveals the diversity of body forms that have evolved independently in different lineages
What is the likely reason for the observed differences in body features between closely related species?
It is due to the loss of body features over the course of evolution
What do animal body plans primarily describe?
Morphological and developmental traits
What is the term 'body plan' meant to imply?
A particular set of integrated morphological and developmental traits
What is the significance of studying animal body plans?
To compare and contrast key animal features
What is a characteristic of the ancestors of the human species?
Adapting to open woodlands and savannas
What is a characteristic of the evolutionary history of biological diversity?
A gradual and steady evolution of species over time
What is the context of the concept of body plans in the study of evolution?
Evo-devo, the interface between evolution and development
What is a characteristic feature of bilateral animals?
The ability to move actively from place to place
What is the significance of the process of gastrulation in animal body plans?
It allows for the formation of true tissues in the body
What is a key difference between radial and bilateral symmetry?
The number of imaginary cuts that divide the animal into mirror-image halves
What is the primary characteristic of animal body plans that have true tissues?
The formation of true tissues through membranous layers
What is the significance of the fossil record in understanding the evolution of bilateral symmetry?
It provides evidence for the origin of bilateral symmetry 550 million years ago
What is the primary characteristic of eumetazoan body plans?
The presence of true tissues
Explore the origin of arthropod body plan through Hox genes, specifically Ultrabithorax and abdominal-A, and how they contributed to the evolution of biological diversity.
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