Animal Form and Function Chapter 33 Invertebrates Part 1Aim: What are characteristics ofinvertebrates?Do Now: What characteristics are unique toanimals?
You Must Know…• The traits from Figure 7.11 which are used to divide the animals into groups• Examples of unique traits for each phylum discussed• The evolution of systems for gas exchange, respiration, excretion, circulation and nervous control
32.1 Kingdom AnimaliaAnimals have the following characteristics:1. They are multicellular heterotrophs2. Most have muscles and nervous tissue3. Most reproduce sexually, with a flagellated sperm and a large egg uniting to form a DIPLOID zygote.4. The diploid stage dominates its life cycle5. Have Hox genes
• Homeotic genes are genes in animals that determine which parts of the body form what body parts. – Hox genes, a family of genes that play important roles in development • segmentation• Highly conserved – Similar sequence in all animals • Small differences in DNA sequences, lead to large differences in body plan
Invertebrate Terms:• Appendages: Any part of the animal coming from the main body or trunk- arms, legs, antennae, etc.• Asymmetry- no symmetrical• Bilateral symmetry- mirror images when cut from head to anus• Radial symmetry- mirror images when cut through the central axis• Dorsoventrally- running from back to front• Exoskeleton- an external skeleton, shell• Endoskeleton- an internal skeleton• Alimentary canal- tube running from mouth to anus, including all of the organs the food passes through• Digestive system- the alimentary canal plus accessory organs (liver, pancreas)
Invertebrate Terms• Segmented: the division of the body into similar parts• Sessile- is not motile; anchored to a substrate• Filter-feeder- collects particles as water flows through them• Gastrovascular cavity- sac-like digestive structure with one opening that serves as the mouth and anus• Gut openings: 0, 1 (same mouth/anus) or 2 (separate mouth and anus)• Cnidocytes/nematocyst- stinging structure• Cephalization- sense organs at anterior (head) end• Open circulatory system- blood is not contained entirely in vessels
InvertebrateTerms• Metazoa: multicellular• Parazoa: lacking true tissues• Eumetazoa: True tissue• Radiata: Radial Symmetry• Bilateria: Bilateral Symmetry• Deuterostomes: deuterostome development• Protostomes: protostome development:• Acoelomate: no cavity• Coelomate: True body cavity• Pseudocoelomate: body cavity from mesoderm and endoderm
Animal Form and Function Chapter 33 InvertebratesAim: What are characteristics ofinvertebrates?Do Now: What do you know aboutinvertebrates? Give several examples.
Invertebrate Phyla Characteristics• Observe one representative organism from each invertebrate phyla• Write the characteristics that you observe for each invertebrate phyla in the phylogenetic tree• Use the “invertebrate terms” notes in your notebook for help with identifying characteristics for each phyla
Invertebrates• Animals that lack backbones• Domain Eukarya• Kingdom Animalia• Invertebrates are classified under many phyla – There is not “Invertebrate Phylum”• Branch “metazoa”- multicellular• Order of invertebrates is in order of evolution- see a pattern of simple to complex in body plan
1. Subkingdom Parazoa: SpongesSubkingdom Parazoatrue tissues) (lacking (sponges)• aka Phylum PoriferaCharacteristics of Sponges:• Sessile (anchored to a substrate) – But embryo is mobile• Lack symmetry• Lack true tissues- Simple! – NO nerves or muscles (= no organs) – No nervous, digestive, or circulatory system
1. Subkingdom Parazoa: Sponges (lacking true tissues)• Use water currents to obtain food, oxygen and remove wastes (“filter feeders”) – life processes are accomplished via CELLS (as opposed to tissues or organ systems) – Cells must be in contact with environment for exchange of food, gas and wastes• No gut opening – *Intracellular digestion: cells engulf food particles by phagocyotosis; vacuoles fuse with lyosomes for digestion• Body looks like a sac with pores (Porifera) in it – their body contains only 2 layers of cells so they can complete all life functions!!
2. Subkingdom Eumetazoa (animals with true tissues)• Subkingdom Eumetazoa (true tissue) – All animals, except for sponges (Parazoa)A. Phylum Cnidaria (hyrdrozoans, jellies, sea anemone, coral) • Radial symmetry • Few cell layers – Have tissues, but no organs • Central digestive compartment known as the gastrovascular cavity – One opening for mouth and anus » Digestion, distribution of nutrients, elimination of wastes » Food gets digested in the cavity, then diffuses into cells, wasted diffuses out of cells and leaves through the cavity. » Extracellular digestion- food breaks down in cavity, not in cells – Nerve net: Decentralized (little or no sense organs), no brain, stimulus felt in entire organism
Phylum Cnidaria: Polyp (sea anemone) and Medusa (jellyfish) forms
Checkpoint1. Compare and contrast the polyp and medusa forms of cnidarians.
Chapter 33 continuedAim: What are characteristics ofeumetazoa?Do now: Describe distinguishingcharacteristics of the following phyla:Porifora and Cnidaria
2. Subkingdom Eumetazoa (animals with true tissues)B. Bilaterally Symmetrical Animals1. Phylum Platyhelminthes (flatworms) • Examples: Planaria, tapeworms, flukes • Flattened bodies with NO segmentation • Cephalization – Ganglia- clusters of nerves near anterior end (head) to detect light • Excretion (removal of waste) by flame bulbs (with flagella) and protonephridia (neph= kidney) • no specialized organs for circulation or gas exchange – Simple diffusion because body is so flat • Gastrovascular cavity with a single opening • aquatic
2. Subkingdom Eumetazoa (animals with true tissues)B. Bilaterally Symmetrical Animals2. Phylum Nematoda (roundworms) – Examples: pinworms, hookworms – Cylindrical body with a tough cuticle – Complete digestive tract (mouth and anus) – No circulatory system • Fluids circulate (diffusion) – Bodies not segmented – Decomposers in the soil
Animal Form and Function Chapter 33 Invertebrates Part 1Aim: What are characteristics of bilateria?Do Now: Describe distinguishing characteristicsof the following phyla: Porifora, Cnidaria,Platyhelminthes, and Nematoda
2. Subkingdom Eumetazoa (animals with true tissues)B. Bilaterally Symmetrical Animals3. Phylum Mollusca – Soft-bodies animals – Examples: slugs, bivalves (clams, etc), snails, squid, and octopuses – Characteristics: 1. Muscular foot for movement 2. Visceral mass containing most of the organs 3. Mantle- secretes a shell
2. Subkingdom Eumetazoa (animals with true tissues)B. Bilaterally Symmetrical Animals3. Phylum Mollusca – *Open circulatory system • The fluid (hemolymph) is not always contained within vessels but sometimes circulates through body sinuses called hemocoel (cavity) – Complete digestive tract (mouth and anus) – Excretion through nephridia (neph=kidney)
Mollusca: Classes• Gastropoda: – snails and slugs• Bivalvia – clams and oysters – Shell in two parts• Cephalopoda – *Cephalization- brain – Closed circulatory system- blood contained in vessels – Squid- shell is reduced and internal – Octopus and squid
Closed vs. Open Circulatory System• Closed: All blood is • Open: Some vessels; contained within organs bathe in vessels hemolymph (blood) – Under pressure – Not under pressure
Checkpoint1. How have bivalves diverged from the basic molluscan body plan?
Animal Form and Function Chapter 33 InvertebratesAim: What are characteristics of invertebrates?Do Now: Describe distinguishing characteristics of thefollowing phyla: Porifora, Cnidaria, Platyhelminthes,Nematoda, and Mollusca
2. Subkingdom Eumetazoa (animals with true tissues)B. Bilaterally Symmetrical Animals3. Phylum Arthropoda (jointed-legged animals) – Ex: lobsters, shrimp, spiders, scorpions, insects, milipedes and centipedes – 1. Segmented with a hard 2. exoskeleton (chitin) and 3. jointed appendages – To grow, they molt or shed their exoskeleton and secrete another one – Well-developed nervous system (sense organs) – open circulatory system- – Various organs for gas exchange: gills, book lungs, tracheal systems
Arthropod Adaptations for Land• Exoskeleton: – Protection – Anchor for muscles – Locomotion – Protection from desiccation (drying out) • Problem or any organisms living on land• Developed sense organs – Simple eye, smell, taste, touch
2. Subkingdom Eumetazoa (animals with true tissues)B. Bilaterally Symmetrical Animals4. Phylum Echinodermata (echinoderms) – Spiny-skinned animals – Examples: sea stars, sea urchins, sand dollars – Larvae have bilateral symmetry; adults have radial symmetry • Closest relative of vertebrate chordates – Have thin skin covering an endoskeleton (calcium carbonate) – Complete digestive tract – Water vascular system (network of internal canals that branch into tube feet used for moving, feeding and gas exchange) – Reproduce sexually or asexually
Echinoderm Adaptations• Spines – Protection• Skin gills – Respiration• Central nerve ring- nervous system• Eyespot at the end of each arm – Light sensitive• NO respiratory system, excretory system or circulatory system – Water vascular system
2. Subkingdom Eumetazoa (animals with true tissues)B. Bilaterally Symmetrical Animals4. Phylum Chordata – Includes two groups of chordates 1. Invertebrate chordates – Lancelets and tunicates 1. Vertebrate chordates – Characterized by vertebrae (backbone) that encloses the spinal cord – Sharks, fish, amphibians, reptiles birds and mammals
Invertebrate ChordataLancelet Tunicate• Few cm long and narrow • Sessile- live on ocean• Water floor• Retain chordate • Bilaterally symmetrical characteristics as an larva adult
Checkpoint1. Describe how sea star tube feet attach to substrates.
March Through the Kingdoms• Fill out the chart for the plant groups and the invertebrate phyla• Classify the list of organisms• Graphic organizer- use your notes to write distinguishing characteristics of each phyla and class• INVERTEBRATE Quiz TOMORROW
Invertebrate Dichotomous Key• Observe characteristics of each organism• Classify each invertebrate using the dichotomous key• Use the key terms on the back to help with distinguishing the characteristics of each organism• Write the answers in your notebook
Invertebrate Activity1. Classify the organisms2. Use the concept map to check your answers3. Write characteristics (using the worksheet and your notes) next to each organism4. Fill in each branch of the phylogenetic tree (on the back of the animal development picture) with the correct characteristic5. Create a dichotomous key for all of the invertebrate pictures- use vocabulary from the sheet provided