Unit 4 Anatomy Form and Function Comparative Anatomy 2024 PDF

Comparative Anatomy Your first anatomy quiz will be next class. Human Body System Human organ systems will be our topic for the next class. Third - Comparative Anatomical Structures Remember - Form (Structure) Definition: the arrangement of and relations between the parts or elements of some...

Comparative Anatomy Your first anatomy quiz will be next class. Human Body System Human organ systems will be our topic for the next class. Third - Comparative Anatomical Structures Remember - Form (Structure) Definition: the arrangement of and relations between the parts or elements of something complex. All of the parts of living organisms have a specific shape and composition that creates that unique part Example ○ Bones of the skeletal system Many small ribs work together to enclose internal organs Bones are made of calcium/cartilage and are very rigid Remember - Function (Purpose) Definition: an activity or purpose natural to or intended for a person or thing. All of the parts of living organisms have a specific focus to reach a specific outcome so that organism can live Example ○ Skeletal system provide support and protection for the individual The ribs protect the most essential internal organs The calcium/cartilage and rigidity provide the best support and protection when compared with muscles or other soft tissue Homologous Structures What is common here, form or function? Turn and talk (explain your answer). Homologous Structures A classical example of homologous structures is the pentadactyl limb in a variety of different animals Mammals, birds, amphibians and reptiles all share a similar arrangement of bones in their appendages based on a five-digit limb Despite possessing similar bone arrangements, animal limbs may be highly dissimilar according to the mode of locomotion: Human hands are adapted for tool manipulation (power vs precision grip) Bird and bat wings are adapted for flying Horse hooves are adapted for galloping Whale & dolphin fins are adapted for swimming Homologous Structures The clue to common descent and a close evolutionary relationship is common structure, not common function. A bird’s wing and a horse’s front limb have different functions but similar structures. They are homologous structures. Find the function on the previous slide’s diagram. Analogous Structures Convergent evolution is the independent evolution of similar features in species with distinct lineages. It may occur when different species occupy the same habitat and are thus subjected to the same selection pressures The shared conditions cause common adaptations to be selected in different species, resulting in structural similarity The clue to common descent is common structure, not common function. We’ll talk more about this when we study Evolution. Body parts that share common function, but not structure, are called analogous structures. They have a very distant evolutionary relationship. Vestigial Structures Vestigial structures are remnants of structures that may have had important functions in an ancestral species, but no longer perform the function for which they evolved in some of the modern descendants. Changes to the environment have rendered these organs redundant and so over time they have lost their functionality These structures are called vestigial organs and demonstrate the evolutionary divergence of a species from a past activity Vestigial Structures Many species of living whales have a vestigial pelvis and leg bones; evidence that they descended from four-legged land-based ancestors. The pelvis and leg bones do not assist modern whales in walking as they did in whales’ ancestors. Thus, the pelvis and leg bones are vestigial – they no longer serve the function for which they evolved – walking. Vestigial Structures Ostriches’ wings are vestigial… they no longer serve the function for which wings evolved–flying. Ostriches’ wings have evolved new functions. They help the birds to: Maintain balance Mate Threaten enemies. Comparative Anatomy Activity The practice activity is on this link What are vertebrates and invertebrates and what are the differences between a Vertebrate and an Invertebrate? Go to this link and read to find out. Invertebrate feeding and digestion ⚫ Invertebrates can either have intracellular or extracellular digestion: ⚫ Intracellular meaning that food is digested within each individual cell of the organism. ⚫ Examples: Sponges ⚫ Extracellular means that digestion occurs inside a digestive tract or cavity, then absorbed into the body. ⚫ Examples: mollusks, worms, arthropods, echinoderms  Invertebrate Digestive Systems Section 29-2 Intestine Gizzard Crop Mouth/anus Pharynx Gastrovascular cavity Mouth Anus Annelid Gastrovascular cavity Cnidarian Pharynx Crop Anus Pharynx Mouth Rectum Mouth/anus Stomach and Intestine Flatworm digestive glands Arthropod  Vertebrate Digestive Systems ⚫ The digestive systems of many vertebrates have organs that are well adapted for different feeding habits. ⚫ Carnivores, such as sharks have short digestive tracts that produce fast-acting digestive enzymes. ⚫ Herbivores have long intestines that have large colonies of bacteria that help in digesting the cellulose fibers in plant tissues.  Section 33-3 The Digestive Systems of Vertebrates Esophagus Shark Salamander Lizard Pigeon Cow Stomach Intestine Liver Gallbladder Pancreas Cloaca Crop Gizzard Cecum Rectum Respiration in animals Aquatic invertebrates ⚫ Aquatic animals have natural moist respiratory surfaces, and some respire through diffusion through their skin and others use gills. Terrestrial Invertebrates ⚫ There are many different respiratory specialized organs in terrestrial invertebrates. ⚫ Spiders use parallel book lungs ⚫ Insects use openings called spiracles where air enters the body and passes through a network of tracheal tubes for gas exchange ⚫ Snails have a mantel cavity that is lined with moist tissue and an extensive surface area of blood vessels.  Section 29-2 Invertebrate Respiratory Systems Tracheal Gill tubes Siphons Movement of water Spiracles Mollusk Insect Airflow Book Spider lung Vertebrate respiratory systems ⚫ Chordates have one of two basic structures for respiration: ⚫ Gills – for aquatic chordates ⚫ Example: tunicates, fish and amphibians ⚫ Lungs - for terrestrial chordates ⚫ Examples: adult amphibians, reptiles, birds, and mammals  Aquatic Gills ⚫ Water flows through the mouth then over the gills Sectionwhere 33-3 oxygen is removed ⚫ Carbon dioxide and water are then pumped out through the operculum Vertebrate Lungs Nostrils, mouth, and throat Trachea Lung Air sac Salamander Lizard Primate Pigeon Invertebrate Circulatory systems ⚫ Invertebrate circulatory system can range from a system where cells simply do diffusion to take in oxygen or systems with many hearts and even systems with one heart. Open circulatory systems ⚫ Blood is pumped through a system of vessels BUT is only partially contained in these vessels. Most of the time the blood is pumped through open cavities. ⚫ This system is beneficial to arthropods and mollusks because the blood comes into direct contact organs and tissues. Closed circulatory systems ⚫ A closed system forces blood through vessels that extend throughout the body of the organism. Since the system is “closed” the blood never leaves the vessels. ⚫ This system is beneficial to larger organisms because the blood is kept at a higher pressure which allows for more efficient circulation within the organism.  Section 29-2 Invertebrate Circulatory Systems Heart-like structure Hearts Small vessels in tissues Heart Blood vessels Sinuses and organs Blood Heartlike vessels structures Insect: Annelid: Open Circulatory System Closed Circulatory System Vertebrate circulatory systems ⚫ Chordate circulatory systems range from a single loop system (found in organisms with gills) to double loop systems. Double-Loop Circulatory System Single-Loop Circulatory System FISHES MOST REPTILES CROCODILIANS, BIRDS, AND MAMMALS Aquatic Invertebrate excretion ⚫ Some aquatic invertebrates simply diffuse ammonia out their bodies into the surrounding water where it is diluted and carried away. ⚫ Example: sponges, cnidarians, and some round worms. ⚫ Other aquatic invertebrates swell up with water, dilute the wastes and excrete the wastes through tiny pores in their skin. Terrestrial Invertebrate excretion ⚫ Many terrestrial invertebrates convert ammonia into urea. ⚫ Urea is a simpler nitrogenous compound that is much less toxic than ammonia. ⚫ This urea is eliminated from the body in urine Invertebrate Section 29-2 Excretory Systems Flame cells Flatworm Excretory tubules Nephrostome Excretory pore Flame cell Excretory tubule Nephridia Digestive tract Annelid Malpighian Arthropod tubules Vertebrate Excretion ⚫ Aquatic vertebrates kidneys and rely on gill slits to release excretory wastes into surrounding water for dilution. ⚫ Terrestrial vertebrates rely on the kidneys to filter out the ammonia and change it into urea and send it to be released in urine. Nervous system ⚫ All animals respond to their environment through specialized cells called nerve cells. ⚫ In most animals nerve cells hook together to form the nervous system. ⚫ Nervous systems can range from fairly simple to extremely complex. ⚫ The arrangement of nerve cells from phylum to phylum can be dramatically different.  Section 29-2 Invertebrate Nervous Systems Vertebrate Nervous Systems Arthropod Brain Ganglia Ganglia Brain Flatworm Mollusk