Biol 1104k Exam 2

Germ Layers

ectoderm, mesoderm, endoderm

Ectoderm

outermost germ layer; produces sense organs, nerves, and outer layer of skin

Mesoderm

middle germ layer; develops into muscles, and much of the circulatory, reproductive, and excretory systems

Endoderm

innermost germ layer; develops into the linings of the digestive tract and much of the respiratory system

Asymmetry

lack of symmetry; cannot be split into equal parts

Radial Symmetry

Symmetry about a central axis.

Bilateral Symmetry

Body plan in which only a single, imaginary line can divide the body into two equal halves.

Coelomate

true body cavity

Acoelomate

No body cavity

Pseudocoelomate

false body cavity

Diploblastic

Having two germ layers.

Triploblastic

3 germ layers

Cephalization

Concentration of sense organs and nerve cells at the anterior end of an animal; having a head and brain

What are the simplest animals?

Porifera (sponges)

Cnidocytes

Special stinging structures on cnidarians that look like small harpoons; used to catch prey

Polyp body form

Cylindar shape with rising tentacles

Medusa body form

umbrella-shaped and free-living

Protostomes

blastopore becomes mouth (mouth first)

Bilateral animals are placed into one of two categories:

Protostomes and Dueterostomes

Duetorostomes

blastopore becomes anus (mouth last)

Radially symmetric animals tend to have how many germ layers?

2 (diploblastic: endoderm and ectoderm)

Bilaterally symmetrical animals tend to have how many germ layers?

3 (triploblastic: endoderm, mesoderm, and ectoderm)

Open circulatory system

A circulatory system that allows the blood to flow out of the blood vessels and into various body cavities so that the cells are in direct contact with the blood

Closed circulatory system

A system in which blood is contained within a network of blood vessels.

incomplete digestive system

A single opening to a pouch-like cavity serves as both mouth and anus

Complete digestive system

Animal has mouth and anus; food travels one way

Animals without circulatory systems rely on what?

Diffusion

Diffusion

Movement of molecules from an area of higher concentration to an area of lower concentration.

Phylum Porifera

Sponges

Phylum Platyhelminthes

flatworms, flukes, tapeworms

Phylum Cnidaria

jellyfish, sea anemones, corals

Phylum Nematoda

roundworms

Phylum Annelida

segmented worms, earthworms, leeches

Phylum Mollusca

mollusks

Phylum Mollusca, Gastropoda

snails and slugs

Phylum Mollusca, Bivalvia

clams and oysters

Phylum Mollusca, Cephalopoda

squid, octopus

Phylum Arthropoda

Insects (arthropods)

Phylum Arthropoda characteristics

Jointed appendages, segmented, exoskeleton, cephalization, open circulatory system

Mantle

Secretes minerals that form the shell; "outer layer"

Gills

Organs that exchange oxygen and carbon dioxide with water

Radula

Tongue-shaped structure used for feeding by snails and slugs

What is the most diverse animal group?

Arthropods

Parts of a segmented body:

Head, thorax, and abdomen

What are the two deuterostome phyla?

Echinodermata and Chordata

Phylum Echinodermata

starfish, sea urchins, sand dollars, and sea cucumbers

Phylum Chordata

Vertebrates: fish, amphibians, reptiles, birds, mammals

Key characteristics of chordates:

1. Notochord

2. Dorsal, hollow nerve cord

3. Pharyngeal slits or clefts

4. Muscular, post-anal tail

What replaces the notochord during development?

Vertebrate

Fins are predecessors to what?

Limbs

Chondrichthyes

cartilaginous fish (sharks, rays)

Swim bladder

a gas-filled sac present in the body of many bony fishes, used to maintain and control buoyancy.

Swim bladders in fish are closely related to which organ in mammals?

The lungs

Adaptations of terrestrial vertebrate:

Respiration, gravity, water loss

Class Amphibia

frogs, toads, salamanders, caecilians

Class Amphibia characteristics

legs, lungs, cutaneous respiration, pulmonary veins, partially divided heart, ectotherms

Which class of animals developed limbs first?

Amphibians

Dual Life

A reference to the metamorphosis that many frogs and salamanders undergo and the unique mix of aquatic and terrestrial phases that are required in their life cycle.

Class Reptilia

turtles, snakes, lizards

Class Reptilia Characteristics

-Tough dry scaly skin

-Internal fertilization

-3 chambered heart in most

-4 chambered heart in some

-Lungs well developed

-Limbs well developed

-Shelled egg

Which group of animals were the first to be independent of water?

Reptiles

Class Aves

Birds

Birds are closely related to:

Theropod dinosaurs (reptiles)

Which group of animals were the first to be endothermic?

Birds

Class Mammalia

mammals

Class Mammalia characteristics

fur/hair

mammary glands

live births (mostly)

types of teeth

4-chambered heart

Placentals

Embryos completely develop inside the female's uterus; long time in uterus

Marsupials

Mammals whose immature offspring complete their development in an external pouch; short time in uterus

Monotremes

Egg laying mammals

Cetaceans

whales, dolphins, porpoises (water mammals)

Circulatory system

A system of pumps and vessels that transport nutrients, dissolved gases, waste, nutrients, and hormones.

Respiration

The process by which cells break down simple food molecules to release the energy they contain.

Transport medium of the circulatory system:

blood

Plasma

Liquid part of blood (55-60% volume)

Erythrocytes

red blood cells

Luekocytes

white blood cells (fight infection)

karyocyte

Cells that form platelets

Platelets

Cells responsible for blood clotting

Hemoglobin

An iron-containing protein in red blood cells that reversibly binds oxygen.

How many molecules are bound by hemoglobin?

4

Erythropoietin

A hormone produced and released by the kidney that stimulates the production of red blood cells by the bone marrow.

synthetic erythropoietin

often used to boost RBC production in patients with suppressed erythropoietic activity

Average life span of red blood cells:

4-6 months

hemolymph

In invertebrates with an open circulatory system, the body fluid that bathes tissues.

Primary benefits of closed circulatory systems:

Higher flow rates and better control of blood flow

Arteries

carry blood away from the heart

Veins

carry blood to the heart