- Name and compare the ten major phyla in terms of major animal characters, unique characters, rough number of species, importance to humans or environment, typical feeding modes, body size and habitat
download the table here, and complete what you can for class 2.
- Diagram and describe three types of symmetry seen in animals, and the characteristics with which they correlate
Fig. 3.3, 3.4 from B2
[include labeling of major axes]
- asymmetrical organisms have amorphous forms that cannot be equally bisected. Sponges only, although colonial forms look asymmetrical, individuals within colony have symmetry.
- radially symmetrical organisms can be divided in MULTIPLE planes about at least one axis. However, in nature, it is rarely "any plane"; these organisms have no "head”; sense organs are distributed around the perimeter; typical of organisms that are sessile, planktonic, or very slow-moving; design makes sense in this context as they cannot control from which direction information (predators, food) will be coming
- bilaterally symmetrical organisms can only be divided in one plane (Right/Left sides); such organisms have a "head" which is specialized for sensing the environment, with sense organs and a 'brain' (concentration of nervous tissue and connections); typical of organisms with directed movement through environment. (Diagram body planes here!)
- Name, diagram and discuss the basic types of coeloms/internal spaces
[B2 Fig 3.5]
- Acoelomate: no internal space
- Psuedocoeolomate: fluid-filled space lined one side (usually outside) by mesoderm. Most common in smaller animals.
- Coelomate: fluid-filled space lined completely by mesoderm
Five potential functions of internal spaces include
- mechanical barrier between endoderm and ectoderm
- allows for development and expansion of new structures
- serves as a storage chamber for body products (e.g. gametes)
- provides a circulation medium
- serves as a hydrostatic skeleton
- Describe what makes an animal, and list at least five characters that make animals unique
- Animals are multicellular heterotrophs that feed by ingestion.
- animals lack cell walls instead, cells are held together by ECM and junctions (below)
- an extra-cellular matrix of proteins and glycoproteins (e.g. collagen)
- special intracellular junctions (septate and tight: Handout, R&B 6.1)
- animals pass through a blastula stage during development
- most animals have muscle and nerve cells for sensation and coordinated movement
- molecular and morphological evidence suggests they probably evolved from colonial protists called choanoflagellates
- Hox genes determine development of major body axes
- Diagram and define the stages of the animal life cycle and their potential evolutionary origins
B2 Fig 3.35
Development typically proceeds through several stages:
- fertilization and formation of the zygote
- mitotic division to form a hollow ball of cells (the blastula)
- infolding of one side of the blastula to form the gastrula. Taxa in which this opening becomes the mouth are called protostomes; Taxa in which this opening becomes the anus are called deuterostomes.
- differentiation into tissue layers (see below)
- some groups develop directly into adults, while others first form larvae, then undergo a major change in body form (metamorphosis) to become the adult.
Blastula and gastrula forms are thought to mimic early stages of multicellular evolution in animals (Handout)
- Diagram the three embryonic tissue layers seen in animals, and explain what tissues, organs and/or systems they become in the animal
Embryonic tissue layers give rise to specific tissues.
- ectoderm becomes the epidermis and, where present, the nervous system
- endoderm becomes the digestive tract
- mesoderm, where present, forms most of the major internal organs, plus muscles and endoskeleton
B2 Fig 4.8
- Define and describe the term Bauplane
A particular way of building an organism; a conserved body plan. (German for "blueprint"). Includes:
- Development
- Level of integration
- Approaches to functional problems
- Correlated with symmetry
-Determines how the organism interacts with other species and the environment
-Implies that "some aspects of embryonic and/or adult morphology are more free to vary than are others"
-May be controlled developmentally by Hox genes (A-P, D-V axes)
- Describe the limits to diffusion through tissue, and how this affects animal form
- metabolic demand of tissue is based on volume, but exchange of materials (oxygen, nutrients, wastes, CO2) is based on surface area
- as given shape is made larger, volume grows at 3/2 the rate of surface area (L cubed vs L squared)
- effective depth of diffusion through tissue is about 0.5 mm, so any organism thicker than 1mm will have metabolic starvation in interior unless something is done
- solutions include:
- staying small
- infolding, e.g. gastrula like form or lungs/circulatory system
- expand in only one or two dimensions (e.g. worms, flatworms) so all tissue still within 1mm
- non living material in center (e.g. cnidarians)
- "cold blooded" animals have lower metabolic rate, so can get away with a bit more thickness
Handout: R&B 4.4, 4.5 and 4.7
- List and describe four levels of integration seen in animals
Levels of organization include:
- cellular: where different cell types are specialized to particular functions
- tissue: where cells of one or several types work together for common function, and are bound together with specialized junctions and basal lamina
- organ: where different tissues are bound together in a structure for one purpose
- organ system: where multiple organs coordinate for a particular function
Handout R&B 4.15
- List and describe five feeding guilds seen in animals and give an example of each.
- Dissolved Organic Matter: direct uptake of basic molecules from aqueous medium. Many phyla may be able to do this, but often not known.
- Macroconsumer: herbivores, predators, scavengers. Take pieces of larger organism, mechanically break apart and swallow for digestion.
- Parasite/symbiont: nutrition taken directly from another organism that does the collecting and processing. Instead must be adapted to remain in or on host, transfer nutrients.
- Suspension: Filter feeding like clams (can be energetically costly due to movement of water through seive), exposed sticky surface such as mucus net or scan and trap small particles.
- Deposit: direct ingestion of soil, or select particles from soil that are organic/humus and ingest those.
- List four functions of skeletons, and three types of skeletons seen in animals
Roles of the skeleton include:
- supporting the body and maintaining shape
- transfer of muscle action
- muscle antagonism
- defense and protection
Rigid element skeletons can be internal (endoskeleton) or external (exoskeleton), and muscle antagonism is based on joints (B2 Fig 3.11). These are better for protection but entail more material that may be heavy. Exoskeletons are excellent protection but impede growth, so must be molted.
Most organisms have some form of hydrostatic skeleton, where the incompressibility of fluid allows sets of muscles to antagonize each other. Hydrostats are also often supplemented by fibers wound at a large angle relative to the body axis (Handout, R&B Fig 6-3). Not as good for protection but less cumbersome.
- Diagram and describe segmentation and its potential purposes
True segmentation involves repetition of body regions, along with associated organ systems (muscles, nerves, blood vessels)
- Some organ systems (digestive, reproductive) differ among segments.
- In the evolution of some groups, segments become joined into larger body regions, with internal structures also combined.
Could have evolved due to:
- adaptation for movement
- easy way genetically to build a larger organism: find plan that works and repeat
Developmental mechanism responsible for segmentation differs among groups
- Name and describe 10 functions every animal must do, including the major steps/structures involved
- feeding and digestion
- acquire and capture food
- ingestion
- mechanical breakdown
- chemical breakdown
- absorb nutrients
- absorb water
- defecation
Handout: Callow: Digestive systems
- gas exchange/respiration
- O2 and CO2 exchange; local conditions
- exchange surface
- move fluid across surface
- architecture of system: dedicated system, passive, internal body space (gastrovascular cavity)
- circulation
- move fluid around to all parts of body
- gas exchange
- nutrients
- waste removal
- architecture of system: open, closed, passive, internal body space (gastrovascular cavity)
- excretion/water balance
- eliminate waste: ammonia
- water regulation
- ultrafiltration, resorb good ions, transport
- movement
- type of movement: amoeboid, ciliary/flagellar, hydrostatic, locomotor
- architecture of system
- support and body shape
- architecture: hydrostatic, rigid: endo, exoskeleton
- muscle antagonism, transfer of motion
- growth
- sensation and coordination/nervous system
- sensory organs/receptors: tactile, geo-, proprio-, phono-, baro, chemo-, photo-, thermo-
- architecture: nerve nets, cephalization, main wires, level of integration
- defense against predators and pathogens
- antipredatory: chemical, physical, behavioral
- immune system: physical, cellular
- reproduction
- sexual: repro organs, gametes formation; fertilization type; incubation
- asexual
- growth and development
- zygote and cleavage; coelom formation; mosaic or regulative embryo?
- larva
- metamorphosis
- adult
- different life forms (e.g. medusa, polyps)
- segmentation
- Compare characteristics from Protostomes and Deuterostomes. Which of the ten major phyla are typically placed in each group, and why they are/are not a good fit.
Discussion in class based on
- Handout- Protostome/Deuterostome diagram
- Phylum table
