Chapter 5. Microbial Heterotrophs and Invertebrates (Protozoans (Phylum…
Chapter 5. Microbial Heterotrophs and Invertebrates
Large widespread phyla
take up about 50%. shelled amoeba that are mostly microscopic. Plankton or benthic
Posses whip-like flagella or cellular extensions (psuedopodia) extended through shell and used for locomotion
: The white cliffs of Dover are mostly made up of Foraminifera tests and coccolith plates
internal skeleton of silica. Use cytoplasmic filaments to move and catch food.
Posses cilia for locomotion, moving water parallel to shell
Tintinnids are the most abundant. Partially enclosed in vase-shaped structure made of stolen coccoliths cemented together and secreted material.
Ciliated tentacles at one end for food collection (bacteria)
Free-living in colonies that live and move in a network of slime. Usually on Seagrasses and benthic algae. Locomotion is possible but still unknown.
sexual and asexual reproduction
Non-photosynthetic and microscopic organisms part of the kingdom Protista (scrap heap kingdom). Individuals are single-celled. 3 phyla, distinguished by locomotion.
Heterotrophic. Posses cell wall fortified with chitin (derived characteristic of protista, animals and fungi)
Some are parasitic, most are
and absorb nutrients from detritus and other non-living organic material by secreting digestive juices externally.
Primary decomposers on earth along with bacteria. Major decomposer of cellulose and lignin in plant cell walls - which bacteria struggle with.
3 types of symbioses relationships: LICHENS = fungi/photosynthetic organism. MYCOPHYCOBIOSES = Marine fungi/seaweed. MYCORRHIZAS = Fungi/vascular plants (not mangrove plants)
Some also cause disease: MYCOPTHOGENS
4 phyla, distinguished by their sexually reproductive methods and structures (most also asexually reproduce).
Most have body called a mycelium composed of filaments called hyphae (High surface area to volume ratio)
Protozoans lack 2 defining features of animals: contractile muscle and signal conducting neurons. Asexual reproduction is common. Porifera and Placozoan cells can function independently
Simplest animal. Consisting of loosely aggregated cells organised into multi-cellular organism. They lack tissue and organs.
Can live long and grow large, attached to hard substrate
Porus, with channels leading to the cavity or spongocoel, then out the osculum. Choanocytes extract oxygen and nutrients.
3 types, defined by their skeleton and complexity
Only one species =
Found in tropic and sub tropic waters gliding along hard surfaces. Mostly pelagic
Move via cilia on both sides of the animal, no obvious symmetry.
Digestion by externally secreted enzymes
Asexually and possibly sexual reproduction
3 phyla have radial symmetry: Cnidaria, Ctenophora (earlier evolution stage) and Echinodermata. Mouth at the center of the oral side. Have a simple network of nerves, but no brain
Large diverse group - Sea anemones, jellyfish, corals and hydroids
Body wall separated by gelatinous mesoglea. Gut is bag-like (gastrovascular cavity), mouth surrounded in tentacles.
Stinging nematocytes, produced by cnidocyte cells are characteristic for this phylum
2 live stages = attached
of free living
3 classes based of life cycle:
- Both stages present.
- Polyp stage reduced or absent.
- Medusa stage absent.
All marine, mostly planktonic and prey on Zooplankton
Very similar and related to Cnidarians, BUT, have complete digestive system and colloblast cells which are like sticky cnidocytes
Have 8 long cilia called ctenes that provide propulsion. Tentacles catch food.
Marine Acoelomates and Pseudocoelomates
Bilateral symmetry and usually possess specialized sensory organs and anterior brains.
3 groups, depending on internal digestive development:
lack a digestive tract;
have a poorly developed one.
Circulation either absent or poor - rely on body contractions.
High surface to volume ratio.
Usually parasitic and include flukes and tapeworms
1 member free living = Tubellaria
Few planktonic, most benthic and bury into sediment/sand of hard substrate
Cilia on outer surface
- Jawed worms
closely related to Tubellaria. Have no anus and are very small
Live on sea floor feeding on bacteria and algae
Most hermaphroditic. Free living larva absent
- Round worms
Common and wide spread
Some parasitic, most free- living and predatory. Found in sediment at almost all sea levels.
inefficient locomotion by quick bending motions
Benthic & colonial.
Secrete thin calcareous encrustations on rock, seaweed and shells
U-shaped digestive tract and tentacle crown enclosing mouth and anus
True internal body cavity.
Heart enhanced circulation.
2 separate lineages based on digestive tract development.
= Spiral pattern of cleavage, determinate development, unequal sized cells & blastopore becomes mouth.
= radial cleavage, inderterminate development, blastopore becomes anus.
= crown of ciliated feeding tenticles found in 3 phyla - Ectoprocta, Phoronida &Branchipoda
= most abundant and found in all major habitats.
Diverse, but a few defining features: Unsegmented, most have shells and large muscular feet used for locomotion, anchorage and feeding.
An array of specialized sense organs (cephalization)
= snails and slugs.
= elongated, tapering shell.
= Mussels, claims, oysters & scallops.
= Squids, octopuses, cuttlefish & nautiluses. Well developed sense organs, brains and eyes.
Unique propulsion system for locomotion.
Nautiluses only class with an external shell, others have an internal or reduced shell.
= Most live in soft mud or deposit
Found throughout the world
= marine worms - Polychaeta.
Segmented into metameric compartments.
Some carnivores, some are suspension feeders
Often occupy partially berried tubes & common in intertidal areas
= Segmented with hard exoskeleton made of chitin in protein matrix (Protection and serves as muscle attachment - must be moulted)
2 completely marine - Merostomata (Horseshoe crab), Pycnogonida (Sea spider)
Crustacea - 2 Antennae and nauplius larval stage, wide range of habitats. Includes Barnacles, Copepods, Shrimp, Crab and lobsters.
Hemichordata, Echinodermata and Invertebrate Chordata
Chordata have, Post-anal tail, gill slits, notocord, dorsal hollow nerve cord at some point in thier life cycle.