A Brief Introduction to A Brief Introduction to Animals!Animals!

Chapter 26Chapter 26

Section 1Section 1

Learning TargetLearning Target

What characteristics do all animals What characteristics do all animals have in common?have in common?

What essential functions do animals What essential functions do animals carry out?carry out?

Phylum Examples Evolutionary Milestone

Porifera sponges multicellularity

Cnidaria jellyfish, hydra, coral tissues

Platyhelminthes

flatworms bilateral symmetry

Nematoda roundworms pseudocoelom

Mollusca clams, squids, snails coelom

Annalida earthworms, leeches segmentation

Arthropoda insects, spiders, crustaceans jointed appendages

Echinodermata starfish deuterostomes

Chordata vertebrates notochord

A Brief Overview…A Brief Overview…

Of all the kingdoms, the animal Of all the kingdoms, the animal kingdom is the most diverse in kingdom is the most diverse in appearanceappearance

Each phylum in the animal kingdom Each phylum in the animal kingdom has its own body planhas its own body plan

One major division that we look at is One major division that we look at is vertebratesvertebrates and and invertebratesinvertebrates

Animals come in many different forms

What is an Animal??What is an Animal??

Animals belong to the kingdom Animals belong to the kingdom Animalia, are multicellular eukaryotic Animalia, are multicellular eukaryotic heterotrophs that do not have cell heterotrophs that do not have cell wallswalls

Over 95% of all animal species are Over 95% of all animal species are often grouped into the invertebrate often grouped into the invertebrate categorycategory

The remaining 5% of animal species The remaining 5% of animal species are vertebratesare vertebrates

What Animals Do to SurviveWhat Animals Do to Survive There are 7 essential functions that all There are 7 essential functions that all

animals carry out in order for survival:animals carry out in order for survival: FeedingFeeding RespirationRespiration CirculationCirculation ExcretionExcretion Response (aka a Nervous System)Response (aka a Nervous System) MovementMovement ReproductionReproduction

FeedingFeeding

We already know the relationships We already know the relationships but but oneone more time: more time: HerbivoresHerbivores CarnivoresCarnivores Filter FeedersFilter Feeders DetritivoresDetritivores Parasite/HostParasite/Host

RespirationRespiration

Aquatic animals breathe oxygen (and Aquatic animals breathe oxygen (and expire carbon dioxide) through gillsexpire carbon dioxide) through gills

Terrestrial animals breathe oxygen Terrestrial animals breathe oxygen (and expire carbon dioxide) through (and expire carbon dioxide) through lungslungs

Thin animals breathe through their Thin animals breathe through their skin via a process called diffusionskin via a process called diffusion

Thin skinned aka diffusion!Aquatic aka gills!

Terrestrial aka lungs!

CirculationCirculation Small aquatic organisms rely solely on Small aquatic organisms rely solely on

diffusion to transport oxygen, nutrients and diffusion to transport oxygen, nutrients and waste products amongst their cellswaste products amongst their cells

Most have some type of heart & circulatory Most have some type of heart & circulatory system to move materials around their system to move materials around their bodybody

There are two types of circulatory systems:There are two types of circulatory systems: Small organisms: open circulatory systemSmall organisms: open circulatory system Large organisms: closed circulatory systemLarge organisms: closed circulatory system

Open Circulatory System

Closed Circulatory System

ExcretionExcretion A primary waste product of cellular A primary waste product of cellular

metabolism is ammonia, which is a metabolism is ammonia, which is a poisonous substance that contains poisonous substance that contains nitrogennitrogen

Most animals have an excretory system Most animals have an excretory system that either eliminates ammonia quickly that either eliminates ammonia quickly or converts it to a less toxic substance or converts it to a less toxic substance that is then removed from the bodythat is then removed from the body

Response (aka a Nervous Response (aka a Nervous System)System)

All organisms need nerve cells to All organisms need nerve cells to survivesurvive

The more complex the animals are, The more complex the animals are, the more complex their nervous the more complex their nervous system becomessystem becomes

MovementMovement

Most animals are motile due to Most animals are motile due to muscle contraction, usually working muscle contraction, usually working in combination with a support in combination with a support structure called a skeletonstructure called a skeleton

Most move with muscles connected Most move with muscles connected

to an endoskeleton or exoskeletonto an endoskeleton or exoskeleton

Movement

Some animals are sessileSome animals are sessile

This means that they don’t moveThis means that they don’t move

Wings Legs

Fins

ReproductionReproduction Some animals reproduce asexuallySome animals reproduce asexually Some animals can switch between Some animals can switch between

asexual and sexual reproductionasexual and sexual reproduction Most animals, however, reproduce Most animals, however, reproduce

sexuallysexually InternalInternal ExternalExternal

Some are even hermaphroditic Some are even hermaphroditic

Trends in Animal EvolutionTrends in Animal Evolution

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

Cell Specialization and Levels of Cell Specialization and Levels of OrganizationOrganization

As animals have evolved, their cells As animals have evolved, their cells have become specialized to carry out have become specialized to carry out different functionsdifferent functions MovementMovement ResponseResponse

Large animals need Large animals need greatergreater body body efficiency in body processes than do efficiency in body processes than do very small animalsvery small animals

Body SymmetryBody Symmetry With the exception of sponges, all With the exception of sponges, all

animals exhibit some type of body animals exhibit some type of body symmetrysymmetry

There are 2 main kinds of symmetryThere are 2 main kinds of symmetry

1. 1. RadialRadial Radial: body parts repeat around the Radial: body parts repeat around the

center of the body (like a bicycle wheel) center of the body (like a bicycle wheel)

sea anemones and sea starssea anemones and sea stars

Body SymmetryBody Symmetry2.2. Bilateral Bilateral Bilateral: only a single imaginary line can Bilateral: only a single imaginary line can

divide the body into two equal halves divide the body into two equal halves worms, arthropods and chordatesworms, arthropods and chordates

Bilateral symmetry involved body parts Bilateral symmetry involved body parts that repeat on sides like mirror imagesthat repeat on sides like mirror images

Radial Symmetry

Bilateral Symmetry

Anterior

Posterior

Ventral

Dorsal

Anterior

Dorsal

Ventral

Posterior

CephalizationCephalization

Animals with bilateral symmetry Animals with bilateral symmetry usually exhibit cephalizationusually exhibit cephalization

Cephalization is the concentration of Cephalization is the concentration of sense organs and nerve cells at the sense organs and nerve cells at the anterior end of the bodyanterior end of the body

CephalizationCephalization

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

Body Cavity FormationBody Cavity Formation

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