COMPARING INVERTEBRATES Chapter 29

Taxonomy The system we use today to name and classify all organisms was developed by Carl Linnaeus. The system we use today to name and classify all organisms was developed by Carl Linnaeus. It is known as the system of binomial nomenclature because every organism has a two part name. It is known as the system of binomial nomenclature because every organism has a two part name. –Ex: Pantera leo –Ex: Homo sapiens In addition, Linneaeus classified every organism into a hierarchy of taxa, or levels of organization. In addition, Linneaeus classified every organism into a hierarchy of taxa, or levels of organization.

Taxonomy--Classification King King Philip Philip Came Came Over Over For For Great Great Spaghetti Spaghetti Kingdom Kingdom Phylum Phylum Class Class Order Order Family Family Genus Genus Species Species

Example Classification Domain Domain Kingdom Kingdom Phylum Phylum Class Class Order Order Family Family Genus Genus Species Species Eukarya Eukarya Animalia Animalia Chordata Chordata Mammalia Mammalia Primate Primate Hominid Hominid Homo Homo sapiens sapiens

Taxonomy All life can be organized into three domains: Bacteria, Archaea, and Eukarya. All life can be organized into three domains: Bacteria, Archaea, and Eukarya.

Bacteria Single celled prokaryotes Single celled prokaryotes Aerobes/anaerobes Aerobes/anaerobes Decomposers Decomposers Pathogens Pathogens some are photosynthetic some are photosynthetic Have no introns Have no introns Includes viruses Includes viruses

Archaea Single celled Single celled Prokaryotes Prokaryotes Extremophiles Extremophiles –Methanogens –Halophiles –Thermophiles

EUKARYA All have nucleus and internal organelles All have nucleus and internal organelles Includes animal and plant cells Includes animal and plant cells Consists of 4 kingdoms Consists of 4 kingdoms KINGDOMS KINGDOMS –Protista –Fungi –Plantae –Animalia

Kingdom: Protista

Kingdom: Fungi

Kingdom: Plantae Multicellular Multicellular Nonmotile Nonmotile Autotrophic (photosynthetic) Autotrophic (photosynthetic) Have cell walls Have cell walls Store sugars as starch Store sugars as starch Alternation of generations Alternation of generations Some have vascular tissue Some have vascular tissue

Kingdom: Animalia Multicelluar Multicelluar Heterotrophic Heterotrophic Eukaryotic Eukaryotic No cell walls No cell walls Most are motile Most are motile Most reproduce sexually and are diploid Most reproduce sexually and are diploid

Two General Groups of Animals Invertebrates Invertebrates –No backbone –Great size range –Sea stars, worms, jellyfish, insects –95% of all animal species Vertebrates Vertebrates –Backbone –Fish, amphibians, reptiles, birds, mammals

What Animals Do To Survive Homeostasis: stable internal environment Homeostasis: stable internal environment Feedback inhibition: the product or result of a process stops or limits the process Feedback inhibition: the product or result of a process stops or limits the process

Evolutionary Trends A. Specialized Cells, Tissues, and Organs As larger and more complex animals evolved, specialized cells joined together to form tissues, organs, and organ systems that work together to carry out complex functions. As larger and more complex animals evolved, specialized cells joined together to form tissues, organs, and organ systems that work together to carry out complex functions.

Evolutionary Trends B. Body Symmetry Radial symmetry – parts are arranged in a circle around a central point Radial symmetry – parts are arranged in a circle around a central point Bilateral symmetry – parts are mirror images of each other (left and right sides) Bilateral symmetry – parts are mirror images of each other (left and right sides) Asymmetrical – no definite shape Asymmetrical – no definite shape

Asymmetrical—Porifera

Evolutionary Trends Whereas primitive animals exhibit radial symmetry, sophisticated animals exhibit bilateral symmetry. Whereas primitive animals exhibit radial symmetry, sophisticated animals exhibit bilateral symmetry.

Evolutionary Trends C. Cephalization Along with bilateral symmetry came the development of cephalization, which is the concentration of sense organs and nerve cells in the front (anterior part) of the body. Along with bilateral symmetry came the development of cephalization, which is the concentration of sense organs and nerve cells in the front (anterior part) of the body. The digestive, excretory, and reproductive structures are located at the back (posterior) end. The digestive, excretory, and reproductive structures are located at the back (posterior) end. Invertebrates with cephalization can respond to the environment in more sophisticated ways than can simpler invertebrates. Invertebrates with cephalization can respond to the environment in more sophisticated ways than can simpler invertebrates.

Evolutionary Trends—Cephalization

Evolutionary Trends D. Segmentation Many animals who exhibit bilateral symmetry also have segmented bodies. Many animals who exhibit bilateral symmetry also have segmented bodies. Segments have often become specialized for specific functions. Segments have often become specialized for specific functions. Segmentation allows an animal to increase in size. Segmentation allows an animal to increase in size.

Evolutionary Trends E. Coelom Formation Germ layers formed early in embryonic development: Germ layers formed early in embryonic development: –Ectoderm (outermost layer) –Mesoderm (middle layer) –Endoderm (innermost layer) The coelom is a fluid-filled body cavity that is completely surrounded by mesoderm tissue. The coelom is a fluid-filled body cavity that is completely surrounded by mesoderm tissue. It represents a significant advance in animal evolution because it provides space for elaborate organ systems. It represents a significant advance in animal evolution because it provides space for elaborate organ systems.

Evolutionary Trends—Coelom Formation Types of body cavities: Acoelomates do not have a coelom (body cavity) between their body wall and digestive cavity. Acoelomates do not have a coelom (body cavity) between their body wall and digestive cavity. Pseudocoelomates have body cavities that are partially lined with mesoderm. Pseudocoelomates have body cavities that are partially lined with mesoderm. Most complex animal phyla are coelomates, meaning they have a true coelom that is lined completely with tissues from mesoderm. Most complex animal phyla are coelomates, meaning they have a true coelom that is lined completely with tissues from mesoderm.

Acoelomate Digestive sac (from endoderm) Tissue-filled region (from mesoderm) Body covering (from ectoderm)

Pseudocoelomate Body covering (from ectoderm) Muscle layer (from mesoderm) Digestive tract (from endoderm) Pseudocoelom

Coelomate Body covering (from ectoderm) Tissue layer lining coelom and suspending internal organs (from mesoderm) Coelom Digestive tract (from endoderm)

Coelomate

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Evolutionary Trends F. Embryological Development Blastopore: first opening during the embryonic stages of an organism

Evolutionary Trends F. Embryological Development Protostome – blastopore becomes the mouth, and the anus forms secondarily Protostome – blastopore becomes the mouth, and the anus forms secondarily Deuterostome – blastopore becomes the anus, and the mouth forms secondarily Deuterostome – blastopore becomes the anus, and the mouth forms secondarily

Trends in Animal Development Radial Symmetry Deuterostome Development Coelom Pseudocoelom Protostome Development Radial Symmetry Three Germ Layers; Bilateral Symmetry Tissues Chordates Echinoderms Arthropods Annelids Mollusks Roundworms Flatworms Cnidarians Sponges Single- celled ancestor

Trends in Animal Development From the Primitive No symmetry or radial symmetry No symmetry or radial symmetry No cephalization No cephalization 2 germ layers 2 germ layers Acoelomate Acoelomate No true tissues No true tissues Little specialization Little specialization Sessile Sessile To the Complex Bilateral symmetry Bilateral symmetry Cephalization with sensory apparatus Cephalization with sensory apparatus 3 germ layers 3 germ layers Pseudocoelomate or coelomate Pseudocoelomate or coelomate Tissues, organs, and organ systems Tissues, organs, and organ systems Much specialization Much specialization Motile Motile

Form and Function in Invertebrates Ch. 29-2

Feeding and Digestion The simplest animals break down food primarily through intracellular digestion, but more complex animals use extracellular digestion. The simplest animals break down food primarily through intracellular digestion, but more complex animals use extracellular digestion. In intracellualar digestion food is digested inside the cells. In intracellualar digestion food is digested inside the cells. –The food size must then be smaller than the cells. In extracelluar digestion, food is broken down outside the cells. In extracelluar digestion, food is broken down outside the cells. –The food size is larger than the cells of the organism.

Patterns of Extracelluar Digestion Some animals such as cnidarians and most flatworms ingest food and expel wastes through a single opening. Some animals such as cnidarians and most flatworms ingest food and expel wastes through a single opening. Some cells of the gastrovascular cavity secrete enzymes and absorb digested food. Some cells of the gastrovascular cavity secrete enzymes and absorb digested food. Other cells surround food particles and digest them in vacuoles. Other cells surround food particles and digest them in vacuoles. More complex animals digest food in a tube called the digestive tract, which may have specialized regions such as stomach and intestines. More complex animals digest food in a tube called the digestive tract, which may have specialized regions such as stomach and intestines.

Arthropod Annelid Flatworm Cnidarian Mouth/anus Mouth Gastrovascular cavity Pharynx Crop Gizzard Intestine Rectum Anus Stomach and digestive glands

Respiration: Gas exchange of O 2 and CO 2 Two key features of all respiratory systems: Respiratory organs have large surface areas that are in contact with air or water Respiratory organs have large surface areas that are in contact with air or water Have ways to keep the gas exchange surfaces moist to allow diffusion to occur Have ways to keep the gas exchange surfaces moist to allow diffusion to occur

Respiration Mollusk Insect Spider Gill Siphons Movement of water Book lung Airflow Tracheal tubes Spiracles

Circulation In an open circulatory system, blood is only partially contained within a system of blood vessels. In an open circulatory system, blood is only partially contained within a system of blood vessels. Blood vessels Sinuses (spongy cavities) Tissues Heart (s)

Circulation In a closed circulatory system, a heart or a heart-like organ forces blood through vessels that extend throughout the body. In a closed circulatory system, a heart or a heart-like organ forces blood through vessels that extend throughout the body. The blood stays within these blood vessels. The blood stays within these blood vessels. Materials reach body tissues by diffusing across the walls of the blood vessels. Materials reach body tissues by diffusing across the walls of the blood vessels. Blood circulates more efficiently in a closed circulatory system. Blood circulates more efficiently in a closed circulatory system.

Insect: Open Circulatory System Annelid: Closed Circulatory System Heartlike structures Blood vessels Heartlike structure Small vessels in tissues Blood vessels Hearts Heart Sinuses and organs

Excretion The excretory system is responsible for removing waste material and conserving water. The excretory system is responsible for removing waste material and conserving water. Waste product is usually nitrogenous, meaning it contains nitrogen. Waste product is usually nitrogenous, meaning it contains nitrogen. This waste is usually in the form of ammonia (NH 3 ), which is very toxic! This waste is usually in the form of ammonia (NH 3 ), which is very toxic!

Excretion In aquatic invertebrates, ammonia diffuses from their body tissues into the surrounding water In aquatic invertebrates, ammonia diffuses from their body tissues into the surrounding water Terrestrial invertebrates convert: Terrestrial invertebrates convert: ammonia  urea (less toxic) Some insects and arachnids convert: Some insects and arachnids convert: Ammonia  uric acid

Excretion Annelid Arthropod Flatworm Malpighian tubules Digestive tract Nephridia Excretory pore Excretory tubule Flame cell Flame cells Excretory tubules Nephrostome

Response—Nervous System The nervous system gathers information from the environment. The nervous system gathers information from the environment. The simplest nervous system, found in cnidarians, are nerve nets. The simplest nervous system, found in cnidarians, are nerve nets.

Trends in the Evolution of the Nervous System Centralization—nerve cells are more concentrated (ex: ganglia) Centralization—nerve cells are more concentrated (ex: ganglia) Cephalization—high concentration of nerve cells in the anterior region (head/front) Cephalization—high concentration of nerve cells in the anterior region (head/front) Specialization—more developed sensory organs Specialization—more developed sensory organs –To detect light, sound, chemicals, movement, etc.

Ganglia Brain Nerve Cells Arthropod Mollusk Cnidarian Flatworm

Movement & Support Most animals use specialized tissues called muscles to move, breathe, pump blood, and perform other life functions. Most animals use specialized tissues called muscles to move, breathe, pump blood, and perform other life functions. In most animals, muscles work together with some sort of skeletal system that provides firm support. In most animals, muscles work together with some sort of skeletal system that provides firm support. Three main kinds: Hydrostatic skeletons Hydrostatic skeletons Exoskeletons Exoskeletons Endoskeletons Endoskeletons

Movement & Support Hydrostatic skeleton Hydrostatic skeleton –No hard structures –Lacks muscles –Water filled cavity (gastrovascular cavity) Exoskeleton or external skeleton Exoskeleton or external skeleton –Outside the body –Hard body covering made of chitin –Has to be shed (molting) Endoskeleton Endoskeleton –Structural support inside the body –Muscles

Reproduction Sexual reproduction is the production of offspring from the fusion of gametes. Sexual reproduction is the production of offspring from the fusion of gametes. –Maintains genetic diversity because it generates new combinations of genes Asexual reproduction Asexual reproduction –Ex: Fragmentation –Ex: Budding –All offspring are genetically identical to parent (clones) –Allows for organisms to produce offspring faster –Genetic diversity decreases  less able to deal with changes

Reproduction Some organisms are hermaphrodites, meaning that they produce both sperm and egg. Some organisms are hermaphrodites, meaning that they produce both sperm and egg.

Reproduction Fertilization: unification of sperm & egg External fertilization External fertilization –Observed in less complex animals –Eggs are fertilized outside the body –Gametes are released in surroundings –Aquatic environment Internal fertilization Internal fertilization –Observed in more complex animals –Eggs are fertilized inside the female’s body –Require specialized organs