Lesson 4.1 – Intro to Animals

Functions Obtain food and oxygen Keep internal conditions stable (homeostasis) Move Reproduce Adaptation: structure/behavior that allows animals to better perform their functions

Classifying Animals Over 1.6 million species, divided into about 35 major groups. Classified based on how closely they are related to other animals Body structure, development, and DNA Divided into vertebrates (with backbone) and invertebrates (without backbone)

Classifying Animals

Classifying Animals

Animals Lesson 4.2 – Body Plans

Organization All animals are multicellular, with different types of tissue (groups of similar cells doing the same function). Organs are made from the same type of tissue to perform a specific function. Groups of organs that work together make organ systems.

Organization

Symmetry Symmetry: balanced display of body parts. Asymmetry: when there is no way to divide the organism to create symmetry. Specialized cells, but no tissue

Symmetry Radial symmetry: many lines can be drawn through a central point to produce mirror images in a circular pattern (sea star and jellyfish). Live in water No heads or specialized sense organs Take in information from all directions

Symmetry Bilateral symmetry: only one line of symmetry down the center to create two identical halves (butterfly, for example). Larger and more complex usually Organ systems, most have heads with sensory organs and brain/nervous tissue Usually quick

Invertebrate Animals What are they?

Invertebrates Animals that do not have a backbone or any bone tissue. Most are limited in size because of support. Ocean-dwelling can grow larger.

Sponges: Phylum Porifera Simplest multicellular animals on Earth. Sessile: they are attached to one spot and do not move. Most in ocean, some freshwater. Body is a collection of cells organized into a body wall. Feed on plankton and tiny organisms in water.

Sponges: Phylum Porifera

Specialized Cells Pore cells- small openings in body, lead to larger canals. The canals open into central space, where small cells with flagella carry water throughout sponge. Some cells act as filters for food and O2. Others digest the materials.

Structure Most sponges have spicules, spines made of hard material that provide shape and support for sponge. Provide protection from other animals. Osculum: expels water that has been filtered.

Reproduction Asexual- budding. Sexual- Male cells released into water, and sometimes female cells are also. Fertilization occurs in the water or inside the cell wall. Fertilized egg becomes larva: immature form of an organism. Larva can swim and attach to ocean floor, where they become sessile.

Invertebrate Animals Cnidarians

Cnidarians: Phylum Cnidaria Found in water Jellyfish, corals, sea anemones, and hydras Eat plankton, fish, and clams Most are sessile, but can pull in food from around them.

Cnidarians All have tentacles– fingerlike extensions that go into the water. Specialized stinging cells for capturing prey and protection from predators. Contains a nematocyst – has a filament inside that is released when prey comes in contact. Wraps around or poisons prey Cnidarians

Cnidarians

Tissue and Body Systems Flexible layers of tissue that, along with cells, make up the body system. Organized around single body opening. Tentacles bring prey into the opening, which leads to a cavity (gut) where digestion takes place. Tissue and Body Systems

Tissue and Body Systems

Tissue and Body Systems Even though they are sessile most their lives, they still move their bodies. Adult jellyfish swim. They sense and respond to prey that tough their tentacles; works like a simple nervous system, a network of nerve cells that form a nerve net.

Reproduction Buds are produced and carried away from the sessile parent in the water – asexual. Male cells are carried to female eggs, resulting in free swimming larva – sexual. Water is essential for cnidarian reproduction.

Life Cycle Jellyfish have several stages. When a larva settles on the ocean floor, it grows into a sessile polyp. The polyp develops buds that are eventually released; they are called medusas. A medusa is an adult jellyfish; mobile.

Body Plan Most have radial symmetry: the body is organized around a central point, the mouth that open to the gut. Allows them to capture food from all directions. Forces them to move by pushing down against the water to propel forward.

Invertebrate Animals Worms

Body Plan Most worms have bilateral symmetry: one half looks just like the other half. Have a forward end where the mouth is (its head) and a rear end for expelling wastes.

Worm body systems Some are simple, some are very complex. Tube-shaped body with a digestive tract. Take in oxygen through their skin, so must live in moist environments or water.

Segmented Worms – Annelida Bodies are broken into segments. Earthworms have organs that make up systems; digestive system leads to the excretory system to remove waste. Burrowing and feeding adds nutrients to the soil it goes through.

Segmented Worms – Annelida Several layers of muscle tissue. Hair-like bristles help anchor them to the soil. Nervous system with a brain and a nerve cord. Circulatory system with several hearts that pump blood throughout the body.

Segmented Worms – Annelida Can reproduce sexually or asexually. Earthworms have male and female parts on one worm. Worms exchange male rep. cells to fertilize their female eggs, which then hatch into larvae.

Flatworms - Simplest bodies Some move with cilia instead of muscles. Absorb nutrients through skin. Many are parasites, such as the tapeworm, that live off of their host organism.

Roundworms - They have muscles to moves; Nervous system and digestive system. Found almost everywhere on Earth; great decomposers on land and in water.

Annelida – Earthworms Dissection Notes Invertebrate Animals Annelida – Earthworms Dissection Notes

Dissection Terms Anterior: refers to the direction of the head Posterior: refers to the direction of the tail Dorsal: refers to the upper surface (back side) Ventral: refers to the under surface (stomach)

Earthworm Taxonomy K: Animalia P: Annelida C: Oligochaeta O: Haplotaxina F: Lumbricidae G: Lumbricus s: terrestris Common name: earthworm

Earthworm Information Bilateral symmetry Has a coelem: hollow space inside the body cavity Setae (hair-like bristles) Cephalization: has a head/brain Complete digestive system Closed circulatory system: all circulating fluid is enclosed in aortic arches (hearts) and blood vessels.

External Anatomy The anterior end begins with the mouth; the posterior end ends with the anus. The mouth is also called the prostomium. The clitellum is a larger, lighter, and smooth segment found in between the two ends. Used mainly for reproduction.

External Anatomy The dorsal surface is the side facing up when the worm moves; it is slightly darker and more rounded than the ventral surface. The dorsal vessel is a dark, long line that can be seen on the dorsal surface. Main function: transport blood through the body.

External Anatomy On the ventral surface, the annelid may feel rough. This is due to setae, paired hair-like structures. Main function: aid in locomotion These is a thin layer covering the epidermis of the worm, called the cuticle.

Internal Anatomy The dorsal blood vessel can be seen internally underneath the skin. Digestive tract: begins with mouth, goes into the pharynx, and then into the esophagus. From here, food goes into the crop and the gizzard before traveling through the intestines to the rear end (anus) of the worm. The nervous system: the cerebral ganglia/brain can be found near the mouth and attaches to the nerve cord.

Internal Anatomy The circulatory system: contains 5 aortic arches (hearts) that are connected to the dorsal vessel and ventral vessel. The reproductive system: Seminal vesicle: male part; two small circular structures found toward the front end of the worm. Seminal receptacle: female part; slightly larger than vesicle and found toward the rear end of the worm. Clitellum: structure used in reproduction to protect eggs; appears larger and smoother than the rest of the worm.

Invertebrate Animals Mollusks (mollusca)

Mollusks All have soft bodies, and many have hard shells to protect them. Oysters, clams, snails, mussels, octopi, squids, and slugs, etc. Land, freshwater, and saltwater Most have well developed body systems.

Mollusks

Mollusks Reproduce sexually All mollusks have a muscular foot and a mantle- a layer of folded skin that protects its internal organs.

Bivalves Shells that are made of two matching halves. When closed, the shell completed covers the body. No distinct head, but they have a mouth and sensory organs. Clams, oysters, mussels

Bivalves Filter-feeders: filter food from surrounding water. Moves by pushing its foot in and out of the shell; can burrow into the sand using foot.

Bivalves Takes in oxygen through gills- organs that filter dissolved oxygen from water. Made of many folds of tissue to create a larger surface area, allowing for higher oxygen intake. Gills also filter food from water.

Gastropods Most diverse group Land: snails and slugs Water: conches, whelks, periwinkles Most have spiral shaped shell.

Gastropods Head is at end of foot; has eyes and tentacles. Most have a radula: shreds their food Some eat animals, most eat plants/algae. Land = lungs; water = gills

Cephalopods Live in saltwater: octopi, squid, chambered nautiluses Most well-developed body system: Brain Nerves Pair of eyes near mouth Foot has tentacles for prey Mantle moves water through the siphon for movement Gills Three hearts

Cephalopods

Cephalopods

Cephalopods No protective shell, except nautilus – separate chambers mostly filled with gas to help float. Some change color, some release ink to confuse predators, move freely.

Adaptations This is a very diverse group that has adapted to survive in different types of environments. The foot Bivalve: simple structure moving in and out of shell. Gastropods: muscles in food allow organisms to glide over the surface to get food. Cephalopods: foot has tentacles to pull food into mouth and help in movement.

Clam – Mollusca Dissection Notes Invertebrate Animals Clam – Mollusca Dissection Notes

Dissection Terms Anterior: refers to the direction of the head Posterior: refers to the direction of the tail Dorsal: refers to the upper surface (back side) Ventral: refers to the under surface (stomach)

Clam Taxonomy K: Animalia P: Mollusca C: Bivalvia O: Unionoida Common name: freshwater clam

Bivalve Facts Bilateral symmetry Complete digestive system Simple nervous system: brain/ganglia and nerve cords Open circulatory system: heart, vessels, open sinuses Respiration: gills (filter feeding) Lack a conspicuous head

External Anatomy External shell with concentric lines to show growth patterns. Umbo: visible hump on the dorsal end of the clam. The oldest growth is farthest from the umbo; the newest growth is nearest to the umbo.

Internal Anatomy

Internal Anatomy Attached to the surface of both shells is the mantle. (2/12) The largest organ right beneath the mantle are the gills. (3/10) Underneath the gills is the visceral mass, which protects the internal organs. (11)

Internal Anatomy Posterior to the visceral mass you can see the rectum, which contains the anus for expelling waste. (5/4) At the anterior and posterior ends, you will also find muscle attachment sites and possible scars. (15/16, 6/7)

Internal Anatomy One of the largest organs internally is the foot. This is a muscle and is generally a darker color. (13/14)

Internal Anatomy

Echinoderms (echinodermata) Invertebrate Animals Echinoderms (echinodermata)

Echinoderms Live in the ocean. Adults have radial symmetry with mouth in the center. Feed off ocean floor. Sea stars, sea urchins, sea cucumbers, sand dollars

Spines and Skeletons They all have spines, some large (urchin) and some small (sea cucumbers). Skeleton is not made of bone – made of stiff, hard plates that lie just below the skin. Some are able to move with flexible skeleton (sea stars), some are not able to move (sand dollars).

Spines and Skeletons

Water Vascular System Water-filled tubes that radiate out from the center of the body. Tiny opening along top of body bring water into the tubes. Each tube has a series of tube feet at its base.

Tube Feet The tube feet have muscles that act like suctions to stick to the ocean floor. Tube feet can also help in finding and eating food: Sea star can surround clam, use tube feet to pull shell apart, and then use its stomach to start digesting the internal mollusk. Ocean Life

Arthropods (arthropoda) Invertebrate Animals Arthropods (arthropoda)

Arthropods Segmented body covered by a hard outer skeleton. Over ¾ of all invertebrates are arthropods. Insects, crustaceans (shrimp), arachnids (spiders). Appeared about 420 million years ago. Land and water dwelling

Exoskeleton and Jointed Parts Exoskeleton: strong outer covering made of chitin that completely covers the body. Has joints- where it is thin and flexible- to allow movement. Normally has three sections: head, thorax, abdomen.

Exoskeleton and Jointed Parts

Exoskeleton and Jointed Parts Legs and other parts, such as antennae. Muscles attach in between segments to help arthropods move. They must shed their exoskeleton as they grow because it doesn’t; called molting

Body Systems Nervous system with brain and sensory organs Digestive system with stomach and intestines Open circulatory system – heart moves blood into the body directly with no blood vessels. Reproduce sexually.

Insects Three body segments, a pair of antennae, and six legs attached to the thorax. Obtain oxygen through spiracles. Many colors and shapes allow them to blend with surroundings. Compound eyes and antennae, wings, etc.

Insects

Insects Many are herbivores with adaptations for the type of plant they eat. Butterflies have tube like mouths to reach nectar. Some insects help plants by acting as pollinators. Some insects harm plants by eating/crushing parts of their bodies.

Insects Some are social insects, like bees and ants, that live in groups to survive. They work together to find food, maintain shelter, and care for offspring. Usually one female, the queen, produces and lays eggs. (reproduce sexually) Bees

Insects Undergo metamorphosis during their life cycle, where their body structure changes dramatically. Complete: Begins as an egg, then larva, then pupa, and then adult. Incomplete/Simple: begin as egg, then hatches into a smaller version of the adult. Also called direct development. Complete vs. Incomplete

Invertebrate Animals Arthropods

Crustaceans Most live in the water – lobster, crab, krill, copepods; some live on land – pill bugs. Three or more pairs of legs and two pair of antennae. Larger crustaceans have gills. Most have circulatory system – heart, no vessels Reproduce sexually; hatch from eggs.

Crustaceans – Eating Habits Some each plants and small animals (lobster/shrimp) Many are scavengers Some are filter feeders (barnacles) Beasts or Beauties?

Arachnids Exoskeleton, jointed limbs, segmented bodies; four pair of legs, no antennae, two body segments. Some are parasites (ticks/mites), others are predators (spiders/scorpions). Predators sting, bite, or inject venom into their prey.

Arachnids Some get oxygen through spiracles. Some spiders have respiratory organs called book lungs.

Spiders Largest group of arachnids. Produce silk to spin webs to capture food. Silk comes out of spinnerets. Spiders

Millipedes Two pair of walking legs on each body segment. Move slowly and eat decaying leaves and plants. Emit foul odor that can harm predators.

Centipedes Move more quickly. One pair of walking legs per body segment. Antennae and jaw-like mouth, as well as pincers on their last segment. They are predators; use jaws/pincers to paralyze prey.