1. Zooplankton in the Sea
Zooplankton are Animal-like organisms that float and drift on the ocean surface
Plankton means “wanderers”
Vary in size
from jellyfish to microorganisms
Most are microorganisms
Foundation of the marine food web
Important source of food for many other organisms
“Spring Blooms” – an increase in zooplankton population
Due to increase in phytoplankton – food for zooplankton

2. 2 Types of Zooplankton: Temporary Plankton (These are animals)
Embryos or larvae of marine organisms:
Fish, crabs, sponges, lobster, clams, and other invertebrates
Spend early part of their life cycle floating and drifting near the surface of the ocean
When they mature, they settle to the bottom, where they develop into adults
Permanent Plankton
Remain in the plankton population throughout their entire life cycle
The copepod is the most numerous and
Tiny shrimp-like animal that feeds on diatoms
In turn, it’s food for other larger zooplankton, small fish and whales
Copepods are an important link in many marine food chains

3. Protozoans An amazing group of animal-like protists
Carry out all necessary life functions within a single cell
Ingestion and digestion
Can capture food
Example - With a ring of cilia around mouth
Ingest food through an oral grove (“mouth”)
Food vacuoles take care of intercellular digestion
Respiration
Aerobic respiration
Transport
Passive diffusion of O2 and CO2
Food vacuoles transport nutrients inside cell
Water balance and excretion
Maintain homeostasis (stable internal conditions) with contractile vacuoles
Sensitivity
Response to external stimuli
Reproduction
Asexually through binary fission or budding
Sexually through conjugation

4. So far, you have learned about:
Prokaryotes – Bacteria
Algae and Plants
Protista
What’s next?

5. Animals
We’ll begin this survey with creatures that are structurally simple, progressing toward those that are complex

6. What is an animal?
Multicellular organism
Consumes food
Able to move

7. Exploring Animals…. Animals are the most diverse of living things
All animals are multicellular heterotorphs
Almost all are (99%) invertebrates, lacking a backbone.
No Cell Walls
Cells of all animals, except sponges, are organized into structural and functional units called tissue.
Active Movement, due to flexibility of cells, and evolution of nerve and muscle tissues.
Sexual Reproduction
Embryonic Development

9. Simple Animals – No Body Cavity
We will start with the simplest of the animal kingdom
sponges, jellyfish, and simple worms
These animals lack a body cavity called a coelom, and are thus called acoelomates
Major organization of the animal body first evolved in these animals

10. Animals…

11. Acoelomate animal: a marine flatworm
Acoelomate animal: a marine flatworm. Some the earliest invertebrates to evolve, marine flatworms posses internal organs by lack a true cavity called a coelom.

12. The Classification of Animals
The kingdom Animalia is divided into two subkingdoms:
Parazoa (sponges)
Eumetazoa (everything else)

13. Parazoa: Sponges
Sponges, Phylum Porifera, are multicellular heterotrophs.
Asymmetrical, lacks a definite symmetry
NO tissue or organs
phylum Porifera, sponges
The simplest animals, the Parazoa, lack both difined tissues and organs.

14. Parazoa: Sponges
phylum Porifera, there are around 5000 species, 150 are freshwater
Abundant at all depths in the sea
Adults are anchored to a submerged object, called sessile.
Multicellular, but there is little coordination among cells
Sponges can reproduce asexually (by budding or from fragments) or sexually.
Exists as aggregates of cells with minimal intercellular coordination

15. Phylum Porifera Sponges range in size and shape.
Up to 2 meters in diameter!
Encrusting, boring, finger, tube or vase shaped.

16. Neighbors
Many organisms, including crabs, nudibranchs, mites, bryozoans, and fish live as commensals or parasites in sponges.

17. Suspension Feeders
Sponges are heterotrophic and feed by filtering plankton and other small organisms from the water
Passing it out through the large opening (osculum) at one end of the body.

18. Suspension Feeders
Sponges are suspension feeders capturing food particles suspended in the water that passes through their body.

20. Suspension Feeders
The sponges have specialized, flagellated cells called choanocytes
These cells move their flagella to draw in water in through pores bringing in food and oxygen and expelling wastes.

21. Types of Cells
Choanocytes, flagellated collar cells, generate a water current through the sponge and ingest suspended food.

22. Suspension Feeders
Choanocytes take in small particles by phagocytosis.
Protein molecules are taken in by pinocytosis.
Sponges can also absorb nutrients dissolved in the water.

23. Choanoflagellates
Choanoflagellates are solitary or colonial protozoans with a flagellum surrounded by a collar of microvilli.

24. Choanoflagellates
Choanoflagellates resemble sponge feeding cells (choanocytes).
Scientists are studying colony formation and cell-to-cell communication in choanoflagellates in search of clues to the evolution of multicellularity.

25. Sponge Anatomy

26. Skeletal Framework
The skeletal framework of a sponge may be fibrous or rigid.
The fibrous part comes from collagen fibrils in the intercellular matrix.
Spongin
Rigid skeletons consist of needlelike spicules.
Calcareous
Siliceous
Composition and shape the spicules forms the basis of sponge classification.

27. Sponge Anatomy
Many sponges have minute needles of calcium carbonate or silica, or a tough protein called spongin, or both.