Bio 2201 Invertebrates The animal kingdom is divided

Bio 2201 Invertebrates

The animal kingdom is divided into two main groups! 1. Vertebrates (have a backbone) 2. Invertebrates (lack a backbone)

Let’s take a closer look at the 8 invertebrate phyla First, inverts are classified based on four (4) main characteristics: 1. Systems 2. Symmetry 3. Presence / absence of a coelom 4. Method of reproduction

Systems For invertebrates the systems only refer to the digestive system, since no other systems are usually present. There are two options: “one way with two openings” or “two ways with one opening”. This refers to nutrition (food) and waste.

Symmetry -This is how we describe the “body plan” of an animal -Through use of an imaginary line we can divide the animal in half to determine symmetry. There are three (3) types of symmetry: Asymmetrical Radial Bilateral

When an animal has bilateral symmetry the body can be divided into 5 regions: Anterior: head region Posterior: rear region Dorsal: back region Ventral: bottom region Lateral: side region The body symmetry of all animals is related to the necessity of them to move in order to obtain food. This is why most sensory organs are located at the anterior end of the animal (cephalization).

Presence or Absence of a Coelom This refers to an organism's “body cavity” The coelom is filled with fluid and holds the digestive tract, as well as other organs, in place. Not present in invertebrates (inverts) Animals with a coelom are called coelomates. Animals without coeloms are called acoelomates. Some animals have a “partial” or very small coelom called a pseudocoelom.

There are three (3) reasons why body cavities are important: 1. Provide space for organs to be suspended and thus not be hurt by muscle pressure and body movement. 2. Provide space for internal organs to to develop and expand. 3. Contain fluids which may assist in transportation and gas/nutrient exchange.

Method of Reproduction o Each invertebrate will be classified under each one of three (3) options: asexual vs. sexual o internal features vs. external features o hermaphrodites vs. separate sexes Hermaphrodite = an organism that contains both male and female reproductive organs.

There are 8 phyla of invertebrates we will cover in this course. 1. 2. 3. 4. 5. 6. 7. 8. Porifera (sponges) think sponges have pores Cnidarians (coelenterata) Platyhelminthes (flat worms) plat = flat in French Nematode (round worm) Anelida (ring worms) Mollusca Arthropoda Echinoderms

Time for. . . ANOTHER TABLE!!!!

Porifera (Sponges) 1. Asymmetric 2. No coelom 3. No digestion 4. Reproduction: a. Asexual b. External Fertilization c. Hermaphrodites 5. Example - Sponge

ENTRANCE (CHECK) Card: 1. Where do we find Sponges? 2. What is the Symmetry of a sponge? 3. Tell me three (3) things you learned in last class. i. Take a peek at your notes if needed but try without first!

Cnidarians 1. Radial symmetry 2. No coelom 3. Two way one opening digestion 4. Reproduction: - Asexual and sexual reproduction - External fertilization

Platyhelminthes (Flatworms) 1. Bilateral Symmetry 2. No coelom 3. Two way, one opening digestion 4. Reproduction: a. Asexual and sexual b. Internal fertilization c. Hermaphrodites and separate sexes 5. Examples = planaria, tapeworm

Nematoda: roundworms 1. Bilateral symmetry 2. Coelom present 3. One way, two opening digestive system 4. Reproduction a. Sexual b. Internal fertilization c. Separate sexes and a few hermaphrodites 5. Examples hookworm and pinworm

Annelida (ringworms) 1. Bilateral symmetry 2. Coelom present 3. One way two opening digestive system 4. Reproduction a. Sexual b. Internal fertilization c. Hermaphrodites and separate sexes 5. Examples - earthworm, leech

Mollusca

Arthropods Means “jointed foot”. Arthropods have jointed appendages and hard exoskeleton Includes Insects, Crustaceans, and Centipedes They are bilaterally symmetrical organisms, with true coelom. They have two body openings and one way complete digestive system. Food is digested extracellularly. They reproduce sexually with species being either of separate sexes or some being hermaphrodites. Fertilization is internal. Their nervous systems are advanced compared to other invertebrates with more advanced brain, ventral nerve cord and ganglia. Their sensory abilities are also advanced. Many have the ability to hear, taste, smell, touch, and see.

Arthropods Excretory system made of Malpighian tubules and green glands o Malpighian tubules are a tubule network that collects liquid wastes and sends them to the hindgut in the form of nitrogenous wastes. Found in insects. o Green glands collect and excrete urine like kidneys. Found in crustacean like the crayfish

Echinoderms. - Means “spiny-skinned” Includes Starfish, Sea Urchins, and Sea Cucumbers They are radially symmetrical organisms True coelom They have two body openings, a one way complete digestive system, and food is digested extracellularly. They reproduce asexually via regeneration and sexual reproduction is only possible through separate sexes. Fertilization is external.

Can you place each of these animals into the appropriate taxa?

Notes 9: Arthropods have more combined species than all other phyla; there are trillions of different insects, but only 7 billion humans. There are 4 reasons that contribute to arthropod success: 1. Exoskeleton 2. Different Body Segments 3. Body Systems 4. Diversity in Nourishment

Exoskeleton of Arthropods - This is composed mainly of chitin - Provides waterproof “armour” - Provides a site for muscle attachment - Sheds periodically so that juveniles may grow into adulthood

Body Segments of Arthropods Allows specialized, distinct regions to be formed A. head - anterior B. thorax - middle C. abdomen - posterior Jointed appendages can attach to these regions and work in sensory reception, eating, moving and reproduction.

Arthropod Body Systems - Digestive - Respiratory - Excretory (green glands and malpighian tubules) - Reproductive - Skeletal - Circulatory( open system) - Nervous system that is well developed with the following features: distinct brain, ventral (belly) nerve cord, sense organs such as eyes, auditory

Diversity in Nourishment of Arthropods a. Most eat plants or plant material a. Others eat animal tissues (such as blood) or full animals http: //shapeoflife. org/video/marine-arthropods-successful-design

The most successful class is class Insecta with 900, 000 known species. • Nearly all are terrestrial with a few freshwater and saltwater forms • Size range is broad from 0. 25 mm for some species of beetles and up to 30 cm for some tropical moths

The success of insects is credited to the following reasons: 1. They are the only invertebrates capable of flying. This allows them to move over great distances to find food, escape predators and spread to new environments. 2. There is tremendous variation in how they are adapted for feeding and reproduction. This allows insects to exist in all kinds of environments and to obtain nourishment from many sources 3. High rate of reproduction and short life cycle. This increases the ability of insects to adapt. 4. Small in size. This means that they do need large areas to live. 5. Adaptations to escape predators

Modified Mouthparts of Insects Sucking Mouthparts o Form a tube that can pierce tissues of plants and animals o i. e. Mosquitoes/Butterflies o Mandibles, maxillae, and parts of the pharynx are fused into a needle like structure Sponging & Lapping Mouthparts o Labium has a modification at its apex o i. e. Fruit and House Flies o Have a pair of soft lobes that serve as food channels o Lap up food or liquefy with salivary secretions

Chewing Mouthparts o Mouthparts adapted for seizing, grasping, & crushing food o Adaptations for herbivores and carnivores o Strong mandibles, toothed plates o Enzymes are secreted from salivary glands that by way of chemical actions can liquefy food to aid in the chewing process

Social Behavior of Bees “Societies” display caste differentiation; there is a clear cut division of labour In such communities, all stages of their life cycles are present (i. e. Larvae, Pupae, and Adults) Activities within these communities are collective, each individual works to benefit the community, they communicate with one another Social Castes of Bees l Queen - single sexually mature female l Drone - sexually mature males that mate with the queen l Workers - Sexually inactive females that care to the colony; they feed young, gather food, and care to the hive

Social Behavior of Bees Castes (form of social stratification - like a hierarchy) are determined by fertilization and by what larvae are fed. Drones develop parthenogenetically - From unfertilized eggs, they are haploid Queens and workers develop from fertilized eggs, they are dipolid (full set of chromosomes) Queens are fed a royal jelly produced by workers. Jelly contains enzymes that allow queen to mature sexually

Vertebrates! (HAVE A BACKBONE) All members of Kingdom Animalia are not in the same phylum. (Notes 8 and Notes 9 explore different phyla) Here we will look at one dominant phylum of Kingdom Animalia: Vertebrates Before dividing the phylum into more specific, Classes, we should note there are three (3) common characteristics of phylum chordata. These three characteristics are distinguishing features.

1. Presence of a notochord - Rod or cartilage running along the dorsal end of the body. - Primitive backbone. - In some verts notochord is only found in embryo.

2. Presence of a Dorsal hollow nerve cord - Nerves branch to all parts of the body

3. Gill Slits found in the pharynx or throat - Sometimes only in the embryo

Vertebrates are a subphylum of Phylum Chordata Only 5% of chordates are not vertebrates They are called Tunicates. (They have no head or brain. See fig. 6. 21 on page 191. )

Common Characteristics of Verts 1. Possess a backbone, which evolves from the notochord, and protects the nerve cord. 1. End of the cord develops into a brain. This process is called, cephalization.

3. Body usually contains a head which contains the brain and most sense organs. 4. A tail is present at some point in development.

5. Contains a jointed endoskeleton. 6. Two pairs of appendages (eg arms & legs).

7. Hearts with 2 to 4 chambers in a closed circulatory system. 8. Use gills or lungs for gas exchange 9. Large coelom that contains major organs 10. Body covered in skin (other structures such as nails, hair, horns, hooves, etc can vary)

Respiratory systems can vary by the way a vertebrate respires, through either the lungs, gills or in rare cases the skin. Some groups will have operculum, which is a protective covering over the gills. Circulatory systems in vertebrates are very similar with one main difference. That is the number of chambers in the heart! (2 being the minimum and 4 being the maximum) Reproductive strategy can be either internal or external. In both fertilization and / or development.

There are 7 main subgroups of vertebrates. 1 is a subphylum and the other 6 are classes. Subphylum Agnatha (jawless fish) Class chondrichthyes (cartilaginous fish) Class osteichthyes (bony fish) Class amphibia Class reptilia Class aves (birds) Class mammalia