Note
Studied by 19 people
Biology 12 February 2025 at 13.19.53 PM
Exam Preparation and Discussion
The professor addressed the importance of putting names on exam papers for identification.
Students were encouraged to review their exams and note what they wrote.
Announcements regarding exam review sessions will occur, and students need to email to confirm attendance.
The materials for review include slides and checklists from the lab sessions.
Study Resources
Recommendations for using the BRC (Biology Resource Center) were given, including access to coaches and tutors.
Students were encouraged to take advantage of study skills help available at no cost.
Deuterostomes Overview
Focus on distinguishing between protostomes and deuterostomes.
Characteristics of deuterostomes include:
Multicellular organisms
Triploblastic with ectoderm, mesoderm, and endoderm
Present bilateral symmetry, with exceptions (e.g., evolved starfish exhibit radial symmetry).
True coelom, fully lined by mesoderm.
Specific development patterns, with important details on embryonic cleavage.
Echinoderms Characteristics
All echinoderms are marine and exhibit:
A water vascular system, functioning similarly to a circulatory system.
A hydrostatic skeleton for movement and flexibility.
Radial symmetry evident in adults, transitioning from bilateral symmetry in larval forms.
Key examples discussed include:
Asteroids (sea stars)
Echinoidea (sea urchins, sand dollars)
Crinoidea (sea lilies)
Chordates Overview
Chordates share four characteristics during at least one life stage:
Notochord
Dorsal nerve cord
Pharyngeal gill slits
Post-anal tail
Groups of chordates include:
Urochordates (sea squirts, tunicates)
Cephalochordates (lancelets)
Vertebrates (including mammals, birds, reptiles, and fish).
Vertebrates Characteristics
Vertebrates develop a backbone (vertebral column).
Identified key features between jawless and jawed vertebrates:
Jawless: hagfish and lampreys (characteristics, feeding methods).
Jawed: cartilaginous fish (sharks and rays) and bony fish (characteristics, reproduction methods).
Fish Types and Feeding Adaptations
Distinction between cartilaginous (Chondrichthyes) and bony fish (Osteichthyes):
Chondrichthyes: cartilaginous skeleton, replaceable teeth, internal gills, and paired fins.
Osteichthyes: bony skeleton, overlapping scales, swim bladder for buoyancy, external fertilization.
Reproductive strategies vary among fish:
Oviparous: eggs laid and fertilized externally.
Ovoviviparous: eggs hatch internally but receive no additional nourishment.
Viviparous: live young born, nourished via placenta-like structures.
Amniotes and Evolution of Terrestrial Life
Amniotes developed the amniotic egg, allowing for life entirely on land without aquatic reproduction links.
Reptiles and mammals transitioned away from aquatic environments due to adaptations in reproduction and breathing.
Summary of Key Characteristics Across Groups
The discussion indicated basic anatomical features to distinguish various classes of vertebrates (e.g., heart structure in crocodilians versus other reptiles).
Emphasized the evolutionary link between fish, amphibians, reptiles, and mammals based on skeletal and respiratory adaptations.
In Phylum Echinodermata, bilateral symmetry is evident primarily in the larval stage. However, adult echinoderms exhibit radial symmetry. This transition from bilateral to radial symmetry is significant in understanding the developmental processes of these organisms.
Oral and Aboral Surface in Echinoderms
Oral Surface: This is the side of the echinoderm that faces downwards and typically contains the mouth. It is where feeding and other vital processes occur.
Aboral Surface: This is the side that faces upwards, away from the substrate. It does not contain the mouth and is usually where the madreporite (a structure involved in the water vascular system) is located.
Understanding the relationship between these surfaces is essential for studying the anatomy and functions of echinoderms.