A Brief Introduction to Animals! Chapter 26 Section 1

Learning Target What characteristics do all animals have in common? What characteristics do all animals have in common? What essential functions do animals carry out? What essential functions do animals carry out?

PhylumExamplesEvolutionary Milestone Poriferaspongesmulticellularity Cnidariajellyfish, hydra, coraltissues Platyhelminthe s flatwormsbilateral symmetry Nematodaroundwormspseudocoelom Molluscaclams, squids, snailscoelom Annalidaearthworms, leechessegmentation Arthropodainsects, spiders, crustaceansjointed appendages Echinodermatastarfishdeuterostomes Chordatavertebratesnotochord

A Brief Overview… Of all the kingdoms, the animal kingdom is the most diverse in appearance Of all the kingdoms, the animal kingdom is the most diverse in appearance Each phylum in the animal kingdom has its own body plan Each phylum in the animal kingdom has its own body plan One major division that we look at is vertebrates and invertebrates One major division that we look at is vertebrates and invertebrates

Animals come in many different forms

What is an Animal?? Animals belong to the kingdom Animalia, are multicellular eukaryotic heterotrophs that do not have cell walls Animals belong to the kingdom Animalia, are multicellular eukaryotic heterotrophs that do not have cell walls Over 95% of all animal species are often grouped into the invertebrate category Over 95% of all animal species are often grouped into the invertebrate category The remaining 5% of animal species are vertebrates The remaining 5% of animal species are vertebrates

What Animals Do to Survive There are 7 essential functions that all animals carry out in order for survival: There are 7 essential functions that all animals carry out in order for survival: Feeding Feeding Respiration Respiration Circulation Circulation Excretion Excretion Response (aka a Nervous System) Response (aka a Nervous System) Movement Movement Reproduction Reproduction

Feeding We already know the relationships but one more time: We already know the relationships but one more time: Herbivores Herbivores Carnivores Carnivores Filter Feeders Filter Feeders Detritivores Detritivores Parasite/Host Parasite/Host

Respiration Aquatic animals breathe oxygen (and expire carbon dioxide) through gills Aquatic animals breathe oxygen (and expire carbon dioxide) through gills Terrestrial animals breathe oxygen (and expire carbon dioxide) through lungs Terrestrial animals breathe oxygen (and expire carbon dioxide) through lungs Thin animals breathe through their skin via a process called diffusion Thin animals breathe through their skin via a process called diffusion

Thin skinned aka diffusion! Aquatic aka gills! Terrestrial aka lungs!

Circulation Small aquatic organisms rely solely on diffusion to transport oxygen, nutrients and waste products amongst their cells Small aquatic organisms rely solely on diffusion to transport oxygen, nutrients and waste products amongst their cells Most have some type of heart & circulatory system to move materials around their body Most have some type of heart & circulatory system to move materials around their body There are two types of circulatory systems: There are two types of circulatory systems: Small organisms: open circulatory system Small organisms: open circulatory system Large organisms: closed circulatory system Large organisms: closed circulatory system

Open Circulatory System Closed Circulatory System

Excretion A primary waste product of cellular metabolism is ammonia, which is a poisonous substance that contains nitrogen A primary waste product of cellular metabolism is ammonia, which is a poisonous substance that contains nitrogen Most animals have an excretory system that either eliminates ammonia quickly or converts it to a less toxic substance that is then removed from the body Most animals have an excretory system that either eliminates ammonia quickly or converts it to a less toxic substance that is then removed from the body

Response (aka a Nervous System) All organisms need nerve cells to survive All organisms need nerve cells to survive The more complex the animals are, the more complex their nervous system becomes The more complex the animals are, the more complex their nervous system becomes

Movement Most animals are motile due to muscle contraction, usually working in combination with a support structure called a skeleton Most animals are motile due to muscle contraction, usually working in combination with a support structure called a skeleton Most move with muscles connected Most move with muscles connected to an endoskeleton or exoskeleton to an endoskeleton or exoskeleton

Movement  Some animals are sessile  This means that they don’t move

WingsLegs Fins

Reproduction Some animals reproduce asexually Some animals reproduce asexually Some animals can switch between asexual and sexual reproduction Some animals can switch between asexual and sexual reproduction Most animals, however, reproduce sexually Most animals, however, reproduce sexually Internal Internal External External Some are even hermaphroditic Some are even hermaphroditic

Trends in Animal Evolution Complex animals tend to have high levels of cell specialization and internal body organization, bilateral body symmetry, a front end or head with sensory organs, and a body cavity Complex animals tend to have high levels of cell specialization and internal body organization, bilateral body symmetry, a front end or head with sensory organs, and a body cavity

Cell Specialization and Levels of Organization As animals have evolved, their cells have become specialized to carry out different functions As animals have evolved, their cells have become specialized to carry out different functions Movement Movement Response Response Large animals need greater body efficiency in body processes than do very small animals Large animals need greater body efficiency in body processes than do very small animals

Body Symmetry With the exception of sponges, all animals exhibit some type of body symmetry With the exception of sponges, all animals exhibit some type of body symmetry There are 2 main kinds of symmetry There are 2 main kinds of symmetry 1. Radial Radial: body parts repeat around the center of the body (like a bicycle wheel) Radial: body parts repeat around the center of the body (like a bicycle wheel)  sea anemones and sea stars  sea anemones and sea stars

Body Symmetry 2. Bilateral Bilateral: only a single imaginary line can divide the body into two equal halves  worms, arthropods and chordates Bilateral: only a single imaginary line can divide the body into two equal halves  worms, arthropods and chordates Bilateral symmetry involved body parts that repeat on sides like mirror images Bilateral symmetry involved body parts that repeat on sides like mirror images

Radial Symmetry Bilateral Symmetry

Anterior Posterior Ventral Dorsal

Anterior Dorsal Ventral Posterior

Cephalization Animals with bilateral symmetry usually exhibit cephalization Animals with bilateral symmetry usually exhibit cephalization Cephalization is the concentration of sense organs and nerve cells at the anterior end of the body Cephalization is the concentration of sense organs and nerve cells at the anterior end of the body

Cephalization As organisms become more complex, there is an increase in cephalization As organisms become more complex, there is an increase in cephalization Nerves gather into ganglia Nerves gather into ganglia Complex animals have a brain Complex animals have a brain

Body Cavity Formation A body cavity is important because it provides a space in which internal organs can be suspended so that are not pressed on by muscles or twisted out of shape by body movements A body cavity is important because it provides a space in which internal organs can be suspended so that are not pressed on by muscles or twisted out of shape by body movements