Lecture 14: Animal Body and Development - BIO153 Diversity of Organisms
KAI NOTES.
What is an Animal?
Three macroscopic kingdoms of Eukarya:
Plantae: Photoautotrophs that fix CO2 using water and sunlight.
Fungi: Chemoheterotropic decomposers digesting food outside their bodies, absorbing nutrients.
Animalia (Metazoa): Chemoheterotropic hunters that internalize food for digestion.
Key Differences Between Animals, Plants, and Fungi
Multicellularity:
Animals, plants, and most fungi are multicellular.
Cell wall presence:
Animals lack a cell wall, while plants have cellulose and fungi have chitin for structural strength.
Structural support:
Animals secrete compounds (like collagen) for support, rather than relying on cell walls.
Life cycle:
Dominated by a multicellular, diploid adult phase; no haploid multicellular form exists.
Digestive Tract in Animals
Key Feature:
Animals possess a digestive tract, serving as a 'bag' for food storage and digestion.
Almost all animals have a digestive tract except for select examples (like sponges).
The formation of the digestive tract is critical in embryonic development.
Development of Animal Embryo
Stages of development:
Zygote: A single cell that undergoes cleavage (successive mitotic divisions without growth).
Blastula: Formed after multiple cleavages, characteristically a single layer of cells surrounding a hollow space (blastocoel).
Gastrulation: The process where part of the blastula's surface folds inward to form the gastrula, leading to differentiation of layers:
Ectoderm: External surface (skin, nervous system).
Endoderm: Internal surfaces (digestive and respiratory tracts).
Mesoderm: Forms later, between ectoderm and endoderm (muscles, skeleton).
Gastrulation Process
Key Terms:
Archenteron: The cavity formed during gastrulation.
Blastopore: The opening into the archenteron, which develops into either a mouth or anus.
Deuterostomes: Animals (like humans) where the blastopore becomes the anus, with a second opening forming the mouth.
Identical Twins Formation
Indeterminate cleavage: Cells in bilateral animals can separate and develop into independent organisms.
Monozygotic twins: Resulting from the splitting of a single embryo.
Dizygotic twins: Result from the fertilization of two separate eggs.
Animal Body Organization
Body plan: The fundamental shape/layout is categorized into three types:
Radial symmetry: Body arranged around a central axis (e.g., jellyfish).
Bilateral symmetry: Body parts arranged around two axes (e.g., humans, dolphins).
No symmetry: e.g., sponges, which can grow into irregular shapes.
Eumetazoa and their Importance
Eumetazoa: All non-sponge animals that possess true tissues.
Basal Eumetazoans: Typically exhibit radial symmetry (e.g., jellyfish).
Bilateria: Animals with bilateral symmetry that comprise three major clades:
Lophotrochozoa: Includes clams, snails, earthworms.
Ecdysozoa: Includes crabs, nematodes, and insects.
Deuterostomia: Includes starfish and chordates (like humans).
Sponges and Choanoflagellates
Sponges: The basal animal group; do not form true tissues, and function as sedentary suspension feeders, drawing water through their pores to filter food.
Choanoflagellates: Closest protist relatives of animals.
Share morphological similarities with sponge cells and provide insights into the origin of animal multicellularity.
Some forms can cluster into colonies, indicating early multicellular behavior.
CHAT NOTES
Here’s a key points summary and mind map based on Justin Sung’s method:
Key Points Summary (BIO153 - Lecture 14: Animal Body & Development)
1. What is an Animal?
Three main Eukaryotic Kingdoms:
Plantae (photoautotrophs, fix CO₂ using sunlight)
Fungi (chemoheterotrophic decomposers, external digestion)
Animalia (chemoheterotrophic hunters, internal digestion)
2. Animal vs. Plants & Fungi
Unique to animals: No cell wall, use collagen for structural support
Plants & fungi: Have cell walls (cellulose in plants, chitin in fungi)
Life cycle mostly diploid, no multicellular haploid phase
3. Digestive Tract & Animal Development
Animals have a digestive tract (except sponges)
Development: Zygote → Cleavage → Blastula → Gastrula
Cleavage: Mitotic divisions without size increase
Blastula: Hollow sphere of cells
Gastrulation: Formation of endoderm, ectoderm, mesoderm
4. Formation of Digestive Tract & Germ Layers
Gastrula forms two openings: Mouth & Anus
Protostomes: Mouth from first opening
Deuterostomes: Anus from first opening (e.g., humans)
Germ layers:
Ectoderm: Skin, nervous system
Endoderm: Digestive/respiratory lining
Mesoderm: Muscles, circulatory system (not in all animals)
5. Animal Symmetry & Body Organization
Radial Symmetry: Central axis (e.g., jellyfish)
Bilateral Symmetry: Left-right division, cephalization (e.g., humans, dolphins)
No Symmetry: Sponges
6. Evolution & Animal Phylogeny
Animals evolved from choanoflagellate protists (~710 MYA)
Sponges: Basal group, lack true tissues
Eumetazoa: All animals with true tissues
Bilateria: Most animals, divided into:
Lophotrochozoa (e.g., snails, worms)
Ecdysozoa (e.g., insects, crabs)
Deuterostomia (e.g., humans, starfish)
Mind Map Structure (Main Topics & Subtopics)
1⃣ What is an Animal?
Plantae, Fungi, Animalia
Internal digestion
2⃣ Animal vs. Plants & Fungi
No cell wall
Mostly diploid lifecycle
3⃣ Digestive Tract & Development
Cleavage → Blastula → Gastrulation
Three germ layers
4⃣ Symmetry & Body Organization
Radial, Bilateral, No symmetry
5⃣ Evolution of Animals
Choanoflagellates → Sponges → Eumetazoa
Bilateria (Lophotrochozoa, Ecdysozoa, Deuterostomia)
Would you like me to create a visual mind map for this? 🚀
Exam Q summary NOTES Co-Pilot
Of course! Here are a few questions that capture key points from the lecture:
1. What distinguishes animals from plants and fungi in terms of structure and nutrient acquisition?
The digestive tract does this. A sac to store and process food.
2. Why is the development of the digestive tract crucial for animals, and how does gastrulation contribute to this process?
Gastrulation is a process that happens after the continuous division of a zygote, making it a cluster of multiple cells called blastula. The cell then bends in classifying the cells into Ectoderm( skin, nervous system ), Endoderm(Liver, respiratory, reproductive), and Mesoderm(Skeleton, muscle, ).
After the gastrulation process occurs on one end of the blastula, it continues to the other end to make the digestive tube and the ends the mouth or anus,
3. What are the three germ layers that develop during gastrulation, and what types of tissues or organs do they give rise to?
Ans in first point above.
4. How does symmetry (radial vs. bilateral) influence the body plan and lifestyle of different animals?
5. What is the significance of sponges in the evolution of animals, and how do their body structures differ from other animal groups?
They have no symmetry and are the earliest of the animalia (metazoa) diverged before the euntazoa which its basal contains mostly radial and the rest bilateral.
6. How do monozygotic and dizygotic twins arise, and what does this tell us about early embryonic development?
It occurs when an indeterminate cleavage occurs splitting the zygote in two, since the cells are not specialized, the zygote develop normally into identical twins
7. What evolutionary relationship exists between choanoflagellates and animals, and what does this suggest about the origin of multicellularity?
Choanoflagellates are protists closest to animals and scientists are looking at them to see where animal multicellularity comes from.
MY NOTES
What is an Animal
Macroscopic kingdoms of Eukarya
Plantae
Fungi
Animalia (Metazoa)
Chemoheterotropic hunters who internalizes their food inside body for digestion
Digestive tract, a primary function to break down complex organic material.
Development of the Animal embryo
Cleavage division
Binary fission without increase in body size
Zygote become blastula
What is Blastula
What is Gastrulation
Folding in of the zygote is gastrulation
2 types of cells
Internal cells, Ectoderm
External cells, Endoderm
Second opening makes the digestive tracts complete, allowing for a mouth (and anus, first opening)
Mesoderm: the third layer of cell
Gastrulation is the beginning of differentiation
•Different cell layers develop into different tissues and organs
• Ectoderm: Skin, hair, nervous systems, jaws, teeth, germ cells, etc.
• Endoderm: Epithelial surfaces of digestive, respiratory, excretory and reproductive tracts, liver, etc.
• Mesoderm: Skeleton, muscle, circulatory systems, etc.
• Not all animals have a mesoderm
ORGANIZATION OF ANIMAL BODY
Body plan:
3 Types
Radial symmetry: As an axis, any part of them cut on its axis will result in similar halves.
Remembering (Step 1)
What is memory retrieval?
The process of recalling information from memory.
List the five kingdoms of life.
Animalia, Plantae, Fungi, Protista, Monera.
Understanding (Step 2)
Explain the process of photosynthesis.
The conversion of light energy into chemical energy in plants.
Summarize the stages of cell division.
Interphase, mitosis, and cytokinesis.
Applying (Step 3)
How would you apply the scientific method to a real-world problem?
Identify a problem, formulate a hypothesis, test through experimentation, analyze data, and draw a conclusion.
Demonstrate how to classify organisms into three domains.
Bacteria, Archaea, and Eukarya based on structural characteristics.
Analyzing (Step 4)
Differentiate between prokaryotic and eukaryotic cells.
Prokaryotic cells lack a nucleus and are generally smaller, while eukaryotic cells have a nucleus and are more complex.
Compare and contrast mitosis and meiosis.
Mitosis leads to two identical cells; meiosis leads to four genetically distinct cells, crucial for reproduction.