Download Introduction to the Animal Kingdom

Introduction to the
Animal Kingdom
Introduction to the Animal Kingdom
• Animals are multicellular eukaryotic heterotroph
whose cells lack cell walls
• Vertebrates: 5% of animal species with
backbones
• Invertebrates: 95% of animal species WITHOUT
backbones
• Cell specialization – special shape, physical
structure, and chemical composition to perform a
special function in a multicellular organism
(Division of Labor)
In Order to Survive, Animals Must:
• Feed –
– Carnivores – eat other animals
– Herbivores – eat plants
– Omnivores – eat other animals and plants
– Parasites – inside or on other organisms and
do them harm
– Filter feeders – strain food from water
– Detritus feeders – feed on dead organic
matter
In Order to Survive, Animals Must:
• Respire –
– Consume oxygen and give off CO2
– Skin, gills, lungs
In Order to Survive, Animals Must:
• Circulate/Internal Transport –
– Must carry O2, nutrients and waste products
to and from internal cells
– Heart and blood vessels in larger animals
– Smaller animals rely on diffusion
In Order to Survive, Animals Must:
• Excrete –
– Small animals – diffusion
– Larger animals – excretory systems (that can
include complex kidneys)
In Order to Survive, Animals Must:
• Respond –
– Nerve cells – brain
– Gather information from environment
– Varies greatly from phylum to phylum
In Order to Survive, Animals Must:
• Move –
– Sessile – one spot, no movement
– Motile – move, muscles and/or skeletons
In Order to Survive, Animals Must:
• Reproduce –
– Mainly sexual, but invertebrates can also
reproduce asexually
– Live birth or eggs
– Direct Metamorphosis – young look like adult
– Indirect Metamorphosis – young →
metamorphosis → adult
Direct Metamorphosis
– Direct – young look like adult
Indirect Metamorphosis
• Indirect – young → metamorphosis → adult
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 sense organs, and a body cavity.
Cell Specialization
• Cell → tissue → organ → organ system →
organism
– Ex. Stomach cell → stomach tissue →
digestive system (mouth, stomach, intestines,
etc) → all organ systems put together
Early Development
• Zygote (fertilized egg) undergoes divisions to
form blastula, or a hollow ball of cells
• Blastula flattens on one side and folds into itself
forming a single opening called a blastopore
• Blastopore leads into center tube running the
length of the developing embryo. This tube
becomes the digestive track
– Protostome – mouth formed first from blastopore
(most invertebrates)
– Deuterostome – anus formed first from blastopore
(echinoderms and all vertebrates)
Early Development
(continued)
• Cells then differentiate into three layers,
called germ layers
– Endoderm – innermost germ layer – forms
linings of digestive track and respiratory
system
– Mesoderm – middle germ layer – forms
muscles, circulatory, reproductive, and
excretory systems
– Ectoderm – outermost germ layer – forms
sense organs, nerves, and outer layer of skin
Early Development
(continued)
Body Symmetry
• Asymmetrical – no symmetry (sponges)
• Radial symmetry – body parts repeat around
center of body (simple animals – sea anemone
and starfish)
• Bilateral symmetry – body can be divided into
two equal halves – left and right sides
–
–
–
–
Anterior – front end
Posterior – back end
Dorsal – upper side
Ventral – lower side
Body Symmetry
Bilateral Symmetry
Radial Symmetry
Posterior end
Dorsal side
Anterior end
Plane of
symmetry
Planes of
symmetry
Cephalization
• Complex animals concentrate sense
organs and nerve cells in the anterior end
of the body, this is called cephalization
– Ganglia – small clusters of nerve cells (simple
animals)
– Brain – clusters of ganglia (more complex
animals)
Introduction to Invertebrates