Ch17_Animals. Animals Multicellular eukaryotes. What is an animal? Animal development. Main differences with plants Main differences with fungi

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1 Animals Multicellular eukaryotes Domain Domain Kingdoms Main differences with plants Main differences with fungi What is an animal? Domain Nutritional mode: Heterotrophic (Ingestive) Level of organization: Multicellular Cells without cell wall Cells organized in tissues, organs, and organ systems Nervous tissue and muscle tissue, are unique to animals Bodies are held together by structural proteins such as collagen Motile (They move!) at least in part of their life cycle Animal development Most animals: Are diploid (2N) Reproduce sexually Proceed through a series of typically similar developmental stages A larva (pl. larvae) is a juvenile, young stage in the development of animals (examples: fish, tadpoles, most aquatic animals)

body structure and embryologic development More

different from all other animals because, sponges

Radial symmetry refers to animals that are identical

Bilateral symmetry exists where there is only one way

(3) The presence or not of a Body cavity, called

tract from the outer body wall (4) Most animals have

2 What is used to classify animals? Biologists categorize animals by: General features of body structure and embryologic development More recently, using genetic data (1) (1) Sponges are different from all other animals because, sponges lack true tissues and organs (2) (2) Body symmetry. Radial symmetry refers to animals that are identical all around a central axis, where the mouth is located. Bilateral symmetry exists where there is only one way to split the animal into equal halves. What is used to classify animals? (3) The presence or not of a Body cavity, called coelom, a fluid-filled space separating the digestive tract from the outer body wall (4) Most animals have three germ layers (group of cells, formed during animal embryogenesis)

Some facts about animals Aquatic Mostly Aquatic, Some parasites Really adapted to land (but not all of them are

Animals in the ocean do not require mechanisms to deal with rapid or extreme changes in the environment Stable

animal diversity on Earth 95% of all animal species are invertebrates (animals without a backbone) Phylum Chordata:

plan: No true tissues with a few cellular types No symmetry: Asymmetric Adults are sessile (permanently attached)

3 Some facts about animals Aquatic Mostly Aquatic, Some parasites Really adapted to land (but not all of them are terrestrial!) Most animals are aquatic! Why is living in the ocean better? Animals in the ocean do not require mechanisms to deal with rapid or extreme changes in the environment Stable properties No risks of dehydration Ion contents in sea similar to cytoplasm: osmotic balance Insects: 65% of the animal diversity on Earth 95% of all animal species are invertebrates (animals without a backbone) Phylum Chordata: Includes the vertebrates (Fish, Amphibians, Reptiles, Birds, Mammals) (1) Sponges (Phylum Porifera) Simplest body plan: No true tissues with a few cellular types No symmetry: Asymmetric Adults are sessile (permanently attached) Feeding by filtering water Asexual reproduction by fragmentation or budding is very common Sexual reproduction: external fertilization and a free-swimming larval stage

(2) Cnidaria (jelly fishes, sea anemones,

Radial symmetry Parts of the body radiate

3) They have tentacles with stinging cells

(attached) Incomplete digestive system Only a

fragmentation or budding Sexual reproduction

Stinging cells Cnidarians are carnivores that

4 (2) Cnidaria (jelly fishes, sea anemones, corals) 1) Evolution to true tissues with different functions Nervous tissue Reproductive tissue Digestive tissue 2) Radial symmetry Parts of the body radiate from the center, where the mouth is located 3) They have tentacles with stinging cells Two basic forms: Medusa (motile) Polyp (attached) Incomplete digestive system Only a mouth/anus surrounded by tentacles Reproduction Some show alternation of generations like in some plants (sexual/asexual) Asexual reproduction produces jellyfishes or polyps (motile), by fragmentation or budding Sexual reproduction produces polyps (sessile) Medusa Polyp Stinging cells Cnidarians are carnivores that use tentacles, armed with cnidocytes ( stinging cells ), to capture prey Informal classification Sea anemones Jellyfish Corals

(3) Comb jellies (Phylum Ctenophora) Ch 7 Radial symmetry like in

A radially arranged rows of ciliated plates for swimming 2.

Adhesive cells for food capture and the NO stinging cells 4.

$long cilia fused at the base Continuous beating refracts light,$ Platyhelmithes) The first and simplest bilateral animals First group

bilaterally Better to swim or crawl in one direction!

behaviors are possible Sexual reproduction becomes dominant, though

5 (3) Comb jellies (Phylum Ctenophora) Ch 7 Radial symmetry like in cnidarians, but comb jellies have 1. A radially arranged rows of ciliated plates for swimming 2. Tentacles not in whorls around the mouth, 3. Adhesive cells for food capture and the NO stinging cells 4. An aboral (top) sense organ Swim with eight rows of ciliary combs long cilia fused at the base Continuous beating refracts light, creating a prism-like multicolor effect (4) Flatworms (Phylum Platyhelmithes) The first and simplest bilateral animals First group to show a central nervous system, that appeared connected with bilaterally Better to swim or crawl in one direction! Allow animals to be more active when hunting More sophisticated behaviors are possible Sexual reproduction becomes dominant, though some (e.g. planarian) reproduce asexually by fragmentation Some are free-living, many are parasites with two different types of hosts Parasitic flatworms are Flukes and Tapeworms

Schistosomiasis: (fluke) diarrhea, liver damage, anemia, lowering of the body s resistance (2 nd most important

in the human host. The fertilized eggs exit the host in feces.

The eggs develop in water into ciliated larvae. These larvae infect snails, the intermediate hosts.

invertebrate, Adult parasite vertebrate Tapeworms: Two hosts: two vertebrates.

ends Tough cuticle covers the body Sexual reproduction, with separate sexes Most are free-living, mostly in the

6 Schistosomiasis: (fluke) diarrhea, liver damage, anemia, lowering of the body s resistance (2 nd most important disease caused by parasites after malaria) Adult parasite infects a vertebrate host Blood flukes reproduce sexually in the human host. The fertilized eggs exit the host in feces. Asexual reproduction within a snail results in another type of motile larva, which escapes from the snail host. The eggs develop in water into ciliated larvae. These larvae infect snails, the intermediate hosts. Larval stage infects an invertebrate host Flukeworms: Two hosts: one vertebrate and one invertebrate Larva invertebrate, Adult parasite vertebrate Tapeworms: Two hosts: two vertebrates. Larva herbivore, Adult parasite carnivore (5) Round worms (Phylum Nematoda) Cylindrical in shape, tapered at both ends Tough cuticle covers the body Sexual reproduction, with separate sexes Most are free-living, mostly in the sediments, being important decomposers Some are harmful parasites in plants or vertebrates The amount of damage is often proportional to the number of roundworms Slight infestation: anemia, Heavy infestation: mental or physical retardation

this group Bilaterally symmetrical, body

develops in the adult form Most mollusks

modified foot Filter feeders (fitler the

7 (6) Molluscs (Chitons, Snails, Slugs, Clams, Squids, Octopi) A Soft body, often covered with a shell, composed of one or more plates is characteristic of this group Bilaterally symmetrical, body divided in three main parts: A muscular foot used for movement A visceral mass housing most of the internal organs A mantle, which secretes the shell if present Sexual Reproduction, with separate sexes A larval and free-swimming stage (trocophore) develops in the adult form Most mollusks have all organs systems present, including Circulatory and respiratory system Radula is unique to mollusks: Ribbon of small teeth used to feed Gastropoda Snails, Slugs, Limpets, Abalones Cephalopoda Squids, Octopuses, Nautilus Bivalves Clams, Mussels, Oysters, etc Carnivores with beak-like jaws surrounded by tentacles of their modified foot Filter feeders (fitler the water to get the food) The mantle cavity of a bivalve contains gills that are used for feeding as well as gas exchange

(7) Segmented worms (Phylum Annelida) 1) First animals with real body segmentation Body consists of a series

fluid, the organs are located in the cavity Most annelids have all organs systems present, including

annelids are: Earthworms, which eat their way through soil Polychaetes, marine worms with segmental appendages

Arthropoda (Crustaceans, Insects, Spiders, Scorpions, Centipedes, Millipedes, Ticks, Mites) The diversity and

appendages Insects make 65% of animals on Earth Exoskeleton: external skeleton present in arthropods is made

) Provides protection and Points of attachment for muscles that move appendages Does not grow with the

8 (7) Segmented worms (Phylum Annelida) 1) First animals with real body segmentation Body consists of a series of similar compartments or segments 2) First animals having a real body cavity (coelom), not filled with fluid, the organs are located in the cavity Most annelids have all organs systems present, including Circulatory and respiratory system Sexual reproduction, usually with separate sexes The three main groups of annelids are: Earthworms, which eat their way through soil Polychaetes, marine worms with segmental appendages for movement and gas exchange Leeches, typically free-living carnivores but with some bloodsucking forms (8) Arthropoda (Crustaceans, Insects, Spiders, Scorpions, Centipedes, Millipedes, Ticks, Mites) The diversity and success of arthropods are largely due to 1) their body segmentation 2) hard exoskeleton 3) and jointed appendages Insects make 65% of animals on Earth Exoskeleton: external skeleton present in arthropods is made of chitin (same stuff that makes cell walls in fungi!) Provides protection and Points of attachment for muscles that move appendages Does not grow with the individual and must be replaced as the animal increases its size: molting All arthropods have all organs systems present, including circulatory and respiratory system Sexual reproduction, with separate sexes

Arachnids Live on land Have 4 pairs of walking legs

antennae Millipedes and Centipedes Millipedes eat

per body segment Centipedes are terrestrial

legs per body segment Crustaceans Are nearly all

appendages, two pairs of antennae Insects Insects

Have 3 pairs of walking legs, one pair of antennae

cucumbers, Brittle stars) 1) Pentaradial symmetry in

side present Body parts radiate from the center

Endoskeleton, hard plates just below the skin 3)

system and tube feet for locomotion A network of

9 Arachnids Live on land Have 4 pairs of walking legs and a specialized pair of feeding appendages, no antennae Millipedes and Centipedes Millipedes eat decaying plant matter Have two pairs of short legs per body segment Centipedes are terrestrial carnivores with poison claws Have one pair of short legs per body segment Crustaceans Are nearly all aquatic Have multiple pairs of specialized appendages, two pairs of antennae Insects Insects live on land, freshwater, and the air! Have 3 pairs of walking legs, one pair of antennae (9) Echinoderms (Sea stars, Sea urchins, Sea cucumbers, Brittle stars) 1) Pentaradial symmetry in the adult form No head and tail, or left and right side present Body parts radiate from the center Bilateral symmetry during the larval stage 2) Endoskeleton, hard plates just below the skin 3) Also unique to echinoderms is a water vascular system and tube feet for locomotion A network of hydraulic canals branching into tube feet that function in locomotion, feeding, and gas exchange Sexual reproduction, with separate sexes

(10) Chordata All chordates share during embryology 1) Notochord: flexible rod Gives origin

Pharyngeal slits Gills in aquatic vertebrates.

consists of three groups of invertebrates: Lancelets are bladelike animals without a cranium.

Hagfishes are eel-like forms that have a cranium.

10 (10) Chordata All chordates share during embryology 1) Notochord: flexible rod Gives origin to the backbone 2) Dorsal, hollow nerve cord Central nervous system (brain + spinal cord) 3) Pharyngeal slits Gills in aquatic vertebrates. Parts of the ear, head, and neck in terrestrial ones 4) Post anal tail 1) 2) 4) 3) Chordates consists of three groups of invertebrates: Lancelets are bladelike animals without a cranium. Tunicates, or sea squirts, also lack a cranium. Hagfishes are eel-like forms that have a cranium. All other chordates are vertebrates, which show segmentation in the backbone and muscles hagfish Hagfish slime Lampreys Are fish that Have a cranium and rudimentary vertebrae But lack jaws and paired fins All ectoparasites lamprey

Fish The two main groups are cartilaginous and bony fish Have

Amphibians Includes frogs, toads, salamanders Were the first

live in dry environments) Lungs (not fully functional) and skin

need to back to the water for reproduction Tadpole (larva)

Reptiles Are the first vertebrates to be fully adapted to land

the young Have hair Most develop the embryo inside the mother

amniotic eggs Birds Are very modified reptiles that have in

11 Fish The two main groups are cartilaginous and bony fish Have jaws and paired fins Are the most diverse group of vertebrates Amphibians Includes frogs, toads, salamanders Were the first tetrapods (vertebrates with 4 legs) Wet skin (not adapted to live in dry environments) Lungs (not fully functional) and skin for gas exchange External fertilization Soft shelled eggs Still need to back to the water for reproduction Tadpole (larva) Gills for gas exchange External fertilization Soft shelled eggs Reptiles Are the first vertebrates to be fully adapted to land Mammals Have mammary glands that produce milk, which nourishes the young Have hair Most develop the embryo inside the mother Waterproof skin Internal fertilization Hard shelled and amniotic eggs Birds Are very modified reptiles that have in addition unique adaptations for flying Hollow bones Feathers Forelimbs modified as wings

The Amniotic Egg Is the sac in which the fetus develops in amniotes.

The placenta, which helps in nutrition and gas exchange, includes the Ch.

arteries of the umbilical cord and returns via the umbilical vein In reptiles and birds AMNION (Water-filled membrane,

Skeletons serve as: Protects the animal Provides points of attachment for muscles Exoskeleton: external skeleton present in

12 The Amniotic Egg Is the sac in which the fetus develops in amniotes. It is a tough but thin transparent pair of membranes, which hold a developing embryo until shortly before birth In mammals The placenta, which helps in nutrition and gas exchange, includes the Ch.21 The amniotic sac, that has the amniotic fluid and the embryo Blood from the embryo travels to the placenta through arteries of the umbilical cord and returns via the umbilical vein In reptiles and birds AMNION (Water-filled membrane, protection and moisture) Skeleton Many animals have some type of support system or skeleton. Skeletons serve as: Protects the animal Provides points of attachment for muscles Exoskeleton: external skeleton present in roundworms and arthropods Chitin insects, spiders, scorpions, centipedes, millipedes Add calcium! crustaceans Does not grow with the individual and must be replaced as the animal increases its size Endoskeleton: internal skeleton present in vertebrates and some echinoderms

13 Temperature regulation Homeotherms / Endotherms: Animals that maintain a constant body temperature, generally higher than the environmental temperature Have internal temperature-regulating mechanisms: birds and mammals Able to adapt to any environment But with a very high metabolism (energy use) Ectotherms: Animals cannot regulate the body temperature Regulate their temperature by moving from one place to another: all others

Ch17_Animals. Animals Multicellular eukaryotes. What is an animal? Animal development. Main differences with plants Main differences with fungi

Ch17_Animals. Animals Multicellular eukaryotes. What is an animal? Animal development. Main differences with plants Main differences with fungi Animals Multicellular eukaryotes Domain Domain Kingdoms Main differences with plants Main differences with fungi What is an animal? Domain Nutritional mode: Heterotrophic (Ingestive) Level of organization: