Chapter 24 (Sec. 1-2)

Animals

Animals

Multicellular, heterotrophic, eukaryotic organisms with cells that lack cell walls.

Multicellularity

Allows for division of labor, specialization of cells

Heterotrophic organisms

Obtain energy from complex organic compounds

Ingestion

Taking in of organic material

Zygote

A diploid cell, the first cell of the new organism

Invertebrates: Worms

Animals without backbones

• Accounts for more than 95% of all animals

Give an example

Blastocoel

The central cavity of the blastula

Vertebrates: Humans

Animals with backbones (aka chordates)

• Fewer than 5% of all animals

Give an example

Blastopore

Formed when an area of blastula begins to collapse

Homeostasis

A constant steady state

Negative Feedback

Occurs when the result of a process limits its process

• Somethings too hot? Cool down.

• Too cold? warm up

Receptors

Cells that are used as information for the nervous system

Indirect Development

Have an immediate larval stage

Larva

A free-living immature form of the organism

Direct Development

The young animal is born/hatched with the same appearance and way of life

Epithelial Tissue

Tissue used for covering

Muscle Tissue

Tissue used for movement

Nervous Tissue

Tissue used for communication

Connective Tissue

Tissue involving bones, cartilage, tendons, ligaments, etc.

Radial and bilateral symmetry

What are the two types of symmetry

Segmentation: earthworms

When a body is composed of a series of repeating similar units

Give an example

Body Support

Diverse means of support

Exoskeleton

Rigid outer covering that protects the soft tissue of many animals

Respiratory system

Used for gas exchange

• Direct though the covering of the body or gills

Circulatory System

System that moves blood and fluid through body

Asymmetrical: sponges

No symmetry

Give an example

Radial Symmetry: jelly fish

Body parts extended outward from the center like the spokes of a wheel

• Have a top and bottom but no left or right

Give an example

Bilateral Symmetry

Divides the body into left and right

Top, Bottom, front, back

What positions do Dorsal, Ventral, Anterior, Posterior represent?

Fertilization

The union of female and male reproductive cells, egg and sperm, forms a zygote

Sperm

Male gamete

• Small, mobile

Egg

Female gamete

• large, has store of cytoplasm and yolk

Cleavage

Division of the zygote following fertilization

• First stage of development

Gastrulation

Formation of the gastrula, a multilayered embryo

Blastula

Hollow ball of cells

Ectoderm: forms outer layer of skin, hair, nails, nervous system

The outer germ layer of the gastrula

What does it form?

Mesoderm: forms organs, skeleton, muscles, inner layers of skin, circulatory system

The germ layer between ectoderm and endoderm

What does it form?

Endoderm: forms the throat gut, liver, and pancreas

The inner germ layer of the gastrula
What does it form?

Cephalization

The concentration of sense organs and nerve cells at their anterior end

Jawless fish: Hagfish

Chordates with no true jaws or teeth, skeletons made of cartilage
Give an example

Chondrichthyes: Sharks

Chordates with jaws, paired fins that give control of body movement, tail fines give thrust

Give an example

Osteichthyes

Boney fish, have true bones

Amphibians: Frogs

Animals that live on both land and on water

• larvae live in water and adults mostly live on land

Give an example

Reptiles: Snakes

Cold-blooded animals with dry scaly skin, well-developed lings, shelled eggs that don’t develop in water, are ectotherms

Give an example

Birds

Likely evolved from dinosaurs, developed about 150M years ago, feathers, light bones, two scale covered legs, front limbs modified into wings

• Considered to be the first endotherms

Mammals

Animals that produce their own milk, give birth, endothermy, breathe air and a four chambered heart

• First appeared around 220M years ago

Cenozoic Era

Age of the Mammals

Monotremes: Platypus

Mammals that lay eggs, endemic (found only) in Australia and New Guinea

Give an example

Marsupials: kangaroos

Mammals that have pouches where the baby develops

Give an example

Placental Mammals

Have embryos that develop completely inside the mammal