Intro to Animals/Fish and Amphibians
Ch. 24/27-28
Chapter 24 Introduction to Animals
Section 1: Animal Characteristics
Section 2: Animal Body Plans
Section 3: Sponges and Cnidarians
24.1 Animal Characteristics
General Animal Features
Introduction to AnimalsChapter 24
The ancestral animals at the beginning of the evolutionary tree are eukaryotic and multicellular.
They developed adaptations in structure that enabled them to function in numerous habitats.
Invertebrates- (Exoskeletons) Hard or tough outer coverings that provide a framework of support
Protect soft body tissues, Provide protection from predators
24.1 Animal Characteristics
Vertebrates- (Endoskeletons) Protect internal organs, Provide support for the body
Provide an internal brace for muscles to pull against
Movement: The evolution of nerve and muscle tissues enables animals to move in ways that are more complex and faster than organisms in other kingdoms.
24.1 Animal Characteristics
Fertilization occurs when the sperm penetrates the egg to form a fertilized egg cell called the zygote.
Internal fertilization- the egg and sperm unite inside the animals body
….humans External fertilization- the egg and sperm unite outside the animals body….fish
24.1 Animal Characteristics
What are the first few phases of early development in most animals. Please provide a visual for full credit.
The zygote undergoes mitosis and a series of cell divisions to form new cells.
24.1 Animal Characteristics
The cells continue to divide, forming a fluid-filled ball of cells called the blastula.
The blastula continues to undergo cell division as some cells move inward to form a gastrula.
24.1 Animal Characteristics
Introduction to AnimalsChapter 24
Introduction to Animals
Tissue Development
Endoderm inner layer of cells in the gastrula
Ectodermouter layer of cells in the gastrula
Mesoderm layer of cells between the endoderm
and ectoderm
24.1 Animal CharacteristicsChapter 24
Introduction to Animals
24.1 Animal CharacteristicsChapter 24
24.2 Animal Body Plans
Introduction to Animals
Evolution of Animal Body Plans
Anatomical features in animals’ body plans mark the branching points on the evolutionary tree.
Relationships on this tree are inferred by studying similarities in embryological development and shared anatomical features.
Chapter 24
Introduction to Animals
Symmetry Similarity or balance among body structures of
organisms Asymmetry Radial symmetry Bilateral symmetry
24.2 Animal Body PlansChapter 24
Introduction to Animals
Body Cavities
Coelomates
Have a fluid-filled cavity with tissue formed from mesodermthat lines and encloses the organs in the coelom
24.2 Animal Body PlansChapter 24
Introduction to Animals
Body Cavities
Pseudocoelomates
Have a fluid-filled body cavity that develops between the mesoderm andthe endoderm rather than developing entirely within the mesoderm
24.2 Animal Body PlansChapter 24
Introduction to Animals
Body Cavities
Acoelomates
Have solid bodies without a fluid-filled body cavity between the gut and the body wall
24.2 Animal Body PlansChapter 24
The mouth develops from the first opening in the gastrula.
Introduction to Animals
Development in Coelomate Animals Protostomes
Deuterostomes The anus develops from the first opening in
the gastrula.
24.2 Animal Body PlansChapter 24
Introduction to Animals
Segmentation
Segmented animals can be “put together” from a succession of similar parts.
Can survive damage to one segment
Movement is more effective
24.2 Animal Body PlansChapter 24
Introduction to Animals
24.2 Animal Body PlansChapter 24
Chapter 28 Fishes and Amphibians
Section 1: Fishes
Section 2: Diversity of Today’s Fishes
Section 3: Amphibians
Vertebrates have a vertebral column and specialized cells that develop from the nerve cord.
The vertebral column, or spinal column, is the hallmark feature of vertebrates.
A vertebral column can start as a notochord made of cartilage that protects the dorsal nerve cord then develop into bone.
Chapter 28 Fishes and Amphibians
Lamprey dissection
Scientists have grouped fishes into three classes based on their body structure.
Jawless Fishes (support system is cartilage) Hagfish feed on soft-bodied invertebrates and
dead or dying fish on the sea floor. Lampreys are parasites that feed by attaching themselves to other fishes.Agnatha
Diversity of Today’s Fishes
All cartilaginous fishes have skeletons made of cartilage.
The flexible skeleton, rows of sharp teeth, a streamlined body, and placoid scales make sharks one of the top predators in the sea.
Skates and rays have flattened bodies that are adapted for living on the ocean floor.
Cartilaginous Fishes
There are two groups of bony fishes: the ray-finned fishes and the lobe-finned fishes.
Thin, spinelike rays support the fins of ray-finned fishes.
Lobe-finned fishes have muscular lobes and joints similar to those of land vertebrates.
Bony Fishes
28.2 Diversity of Today’s Fishes
Fishes and Amphibians
Evolution of Fishes
Chapter 28
Jaws: Anterior gill arches evolved into jaws in ancient fishes.
The development of jaws allowed ancient fishes to prey on a larger range of animals.
Fishes
Paired Fins: A fin is a paddle-shaped structure on a fish or other aquatic animal that is used for balance, steering, and propulsion.
Paired fins reduce the chance of rolling to the side and allow for better steering during swimming.
Fishes
Scales
There are four types of fish scales.
Fishes and Amphibians
Ctenoid scales
Cycloid scales
Placoid scalesGanoid scales
28.1 FishesChapter 28
Gills: Fishes get oxygen when water that enters their mouths flows across their gills, where oxygen from the water diffuses into the blood. (Pressure: Volume relationship!!)
Gills are composed of thin filaments that are covered with highly-folded, plate-like lamellae.
Fishes
Circulation
Vertebrates have a closed circulatory system.
Fishes and Amphibians
In most fishes, the heart consists of two main chambers—the atrium and the ventricle.
28.1 FishesChapter 28
Fishes and AmphibiansChapter 28
Feeding and Digestion
Most fishes swallow their food whole, passing it through a tube called the esophagus to the stomach, where digestion begins.
Fishes and Amphibians
28.1 FishesChapter 28
Explain the importance of the lateral line and the swim bladder. How does each work?
Fishes
The Brain and Senses
Color vision, chemical detection, hearing, and balance are coordinating in the brain.
Fishes and Amphibians
The lateral line system is a special sensor that allows fish to detect even the slightest movements in water.
28.1 FishesChapter 28
Reproduction
The majority of fishes reproduce through external fertilization.
Fishes and Amphibians
Male and female fishes release their gametes near each other in the water in a process called spawning.
28.1 FishesChapter 28
Movement
Fishes are well adapted to swimming in the water.
28.1 Fishes
Fishes and Amphibians
Streamlined shape Paired finsSwim bladder
Fishes move through the water by contracting muscle groups on either side of their bodies.
Chapter 28
What are the four differences between the lamprey and the perch.
Lamprey and Perch
Fishes and Amphibians
28.3 Amphibians: Chapter 28
Characteristics of Amphibians
Most amphibians begin life as aquatic organisms.
Fishes and Amphibians
After metamorphosis, they are equipped to live life on land.
28.3 AmphibiansChapter 28
Tadpole
Frog
Feeding and Digestion
Most frog larvae are herbivores, whereas salamander larvae are carnivores.
Fishes and Amphibians
As adults, their diets are similar as both groups become predators. Intestines must shorten.
The digestive system of an amphibian is very similar to that of a fish.
28.3 AmphibiansChapter 28
Respiration
As larvae, most amphibians exchange gases through their skin and gills.
Fishes and Amphibians
As adults, most breathe through lungs, their thin, moist skin, and cavities in the mouth.
28.3 AmphibiansChapter 28
Fishes and AmphibiansChapter 28
Circulation
Amphibians have a double-loop circulatory system.
Fishes and Amphibians
Amphibians have three-chambered hearts.
28.3 AmphibiansChapter 28
Fishes and AmphibiansChapter 28
Reproduction and Development
In most amphibians, fertilization is external and the shell-less eggs must be laid and fertilized in water.
Fishes and Amphibians
Tadpoles hatch from the egg and undergo metamorphosis from a fishlike animal to an air-breathing one.
28.3 AmphibiansChapter 28
Amphibian Diversity
Scientists classify modern amphibians into three orders.
Fishes and Amphibians
Order Anura includes frogs and toads.
Order Caudata includes salamanders and newts.
Order Gymnophiona includes caecilians. Legless and wormlike!! Page 839.
28.3 AmphibiansChapter 28
Evolution of Amphibians
28.3 Amphibians
Fishes and AmphibiansChapter 28