Presentation on theme: "Invertebrate Diversity and Characteristics"— Presentation transcript:
1Invertebrate Diversity and Characteristics Selected topics chosen from Chapters 23-24
2Kingdom Animalia Animals are the most physically diverse kingdom of organisms. Animals range in size from 25-meter-long blue whales to microscopic rotifers.Animals are found nearly everywhere on Earth.
3Each animal phylum has a unique body plan. Vertebrates have an internal segmented backbone.An endoskeleton allows vertebrates to grow to large sizes.internalmade of bone or cartilageInvertebrates do not have a backbone.Invertebrates encompass most animal groups.
4Differences in body plans result from differences in the expression of Hox genes. Hox genes tell embryonic cells which body part to become.Mutations in Hox genes led to the vast diversity of animal species.headtailfruit flygeneshumanHOX-B genes
5Animals are grouped using a variety of criteria. 3 criteria are used to categorize animals:body plan symmetrytissue layersdevelopmental patternsgastrovascular cavitymouthmesogleaoral armstentaclesblood vesselsbrainheartsmusclesegmentnerve cordmouthdigestive track
6There are 3 types of body plan symmetry. 1. bilateral symmetry: body divides equally along one planeAnimals with bilateral symmetry can be divided equally along only one plane, which splits an animal into mirror-image sides.2. radial symmetry: body arranged in circle around a central axis (usually the mouth)3. asymmetry: body has no general plan or central axis. It is irregular in shape.Animals with radial symmetry have body parts arranged in a circle around a central axis.
7Bilateral animals have three distinct layers of tissue; radial animals have only two. both animal types have ectoderm (outer layer) and endoderm (inner layer)bilateral animals have mesoderm (middle layer)Animals are divided into two major groups, the protostomes and the deuterostomes.Protostomes form mouth-first, and anus second.Deuterostomes first form the anus and then the mouth.
8A comparison of structure and genetics reveals the evolutionary history of animals. Protostomes and deuterostomes are the two major radiations on the animal phylogenetic tree.PoriferaCnidariaPlatyhelminthesAnnelidaMolluscaNematodaArthropodaEchinodermataChordataRADIALNO TISSUESPROTOSTOMESDUETEROSTOMESjellyfish, coral, anemonesspongesflatwormsSegmentedwormsclams, snails,octopusesroundwormsinsects, spiderscrustaceans,sea urchinssea stars,vertebrateslancelets,
9Sponges have specialized cells but no tissues. Sponges are the most primitive animals on Earth.570 million-year-old fossilsclosely related to group of protistssessilereproduce both sexually and asexuallyfilter feeders
10Cnidarians are the oldest existing animals that have specialized tissues. Cnidarians have two body forms.polypsmedusasIn the polyp formof a coral, the tentaclesand mouth face upward.In the medusa form of a jellyfish, the tentacles andmouth face downward.
11Flatworms are simple bilateral animals. Flatworms have a solid body and incomplete or absent gut.There are three classes of flatworms.Flukes: Parasites that feed on the body fluids of other animals. Larva penetrate through human skin into blood vessels to settle in human intestine. Treatable.Tapeworms: parasites that live in vertebrate guts. Absorb nutrients from digested food by latching sucker like mouth to intestinal wall. Treatable.Planarians: free-living, nonparasitic flatworm. Lives in ocean.
12Mollusks are diverse animals. Mollusks have a complete digestive tract and a mantle.A complete digestive tract has two openings: a mouth and an anus.Mantle is a hard shell to protect animal.
13Annelids have segmented bodies. Segmentation refers to the repeated sections of an annelid’s body.The coelom is a fluid-filled space completely surrounded by muscle.There are three groups of annelids: Earthworms, marine worms, leechesblood vesselsmuscleheartsbrainmouthdigestive tractnerve cordsegment
14Roundworms shed their stiff outer skeleton as they grow. Roundworms are protostomes with bilateral symmetry.Roundworms have a tough outer skeleton called a cuticle made of chitinMany roundworms are parasites.Nearly every plant and animal species are parasitized by roundworms.hookwormspinwormsGuinea wormsHookworms: feed on host’s blood. Contract it by walking barefoot over contaminated soil.Guinea worms: found in connective tissue of host. Occurs when host drinks contaminated water. Wrap worm around stick and turn it once a day. If worm breaks, it will be difficult to extract from body again.The most common symptom of pinworms is an itchy rectal area. Symptoms are worse at night when the female worms are most active and crawl out of the anus to deposit their eggs. Adults live in gut of host.
15Echinoderms have radial symmetry. Echinoderms have a water vascular systema series of water-filled ring canals around central diskcanals store water used for circulation and movementchanges in water pressure extend and retract tube feetEchinoderms have a complete digestive system.Some echinoderms can regenerate limbs or other body parts.Echinoderm means “spiny skin”tube feet
16Arthropods are the most diverse of all animals because they have features that are highly adapted. Arthropods are invertebrates that share several features.exoskeleton (cuticle) made of chitin that will moltjointed appendagessegmented body partsCompound eyeExternal sensory organs (antennae and body hairs
17Crustaceans—live in oceans, freshwater streams, and on land Trilobites—extinct, bottom feeders; oldest fossils date back 540 million years.Insects—most live on land, have six legsChelicerates—specialized daggerlike mouthpartsMyriapods—long bodies and many pairs of legs
18Arthropod exoskeletons serve a variety of functions. Joints are made of stiff and flexible cuticle to allow movement.The exoskeleton is made of many layers of chitin.hard material that protects the bodymust be shed in order to growArthropods have an open circulatory system.Sensory organs such as antennae are made of modified cuticle.Most arthropods have compound eyes.
19Crustaceans evolved as marine arthropods. Crustaceans share several common features.two distinct body sections: cephalothorax and abdomenone pair of appendages per segmenttwo pairs of antennaeexoskeletonCarapace
20Crustacean appendages can take many forms. Crustacean appendages are used for a variety of functions.collecting and manipulating foodattracting femalesprotectionAppendages include claws, antennae, walking legs, swimmerets, and mandibles.Decapods such as lobsters and crabs have ten legsBarnacles are sessile filter feeders wrapped in a hard shell.
21Arachnids include spiders and their relatives. Arachnids are a group of chelicerates that live on land.eight legsfanglike pincers that inject venomsilk glandsAll spiders make silk and produce venom.Arachnids also include mites, ticks, chiggers, and scorpions.horseshoe crabs
22Insects are the dominant terrestrial arthropods that show an amazing range of adaptations. Insects are in nearly every ecological niche.Insects have a body with three parts.headthoraxabdomenabdomenthoraxheadSome insects live independently, others live in social colonies.
23Insects undergo metamorphosis. In incomplete metamorphosis, insects look like miniature adults when they hatch.There are three life stages of incomplete metamorphosis.larvanymphadultnymph stagelarvaeadult
24In complete metamorphosis, the insect changes form entirely. LarvaEggPupaAdultThere are three life stages of incomplete metamorphosis.egglarvapupaadult
25Arthropods and humans interact in many ways by sharing many of the same resources. Many arthropods are herbivores that eat plants that humans depend on.Arthropods cause millions of dollars of crop damage.Insecticides have unwanted side effects.
26Scientists have developed safer insecticide alternatives. arthropod-specific insecticidesintegrated pest management (IPM) reduces pests by managing their ecology. Ex. Use insect traps, physical barriers, or introduce natural predators.genetically modified crops
27Some arthropods can spread human diseases. Vectors are organisms that carry disease from one host to another.Diseases spread by arthropods have serious effects on human populations.Bubonic plague is caused by a bacterium carried by fleas.Yellow fever is caused by a virus carried by mosquitoes.Malaria is caused by a protozoan parasite carried by mosquitoes.West Nile virus is caused by a virus carried by mosquitoes.