Chapter 32 Flashcards
2 Divisions of animal kingdom
Parazoa
Eumetazoa
Kingdom Animalia 9 general characteristics
Heterotrophy
Multicellularity (Complex bodies)
No cell walls
Active movement (more rapid and complex)
Diversity of form (morphology)
Diversity of habitat
Sexual reproduction (Most do)
Embryonic development
Tissues (many cells working together for same function)
4 Types of eaters
Herbivore - Plant material
Omnivore - Plant and meat/tissue
Carnivore - Other animals (Meat/tissue)
Detritivore - Dead things
Lack of cell walls
Lack rigid cell walls and are flexible. May have extra layer that limits flexibility (Exoskeleton or proteins (collagen)
Extra cellular frame.
Embryonic development
Blastula
Gastrula
Starts with sperm and egg and then the zygote is the 1st 2n cell which performs mitosis rapidly.
Blastula - # of cells clustered together. Can fold in on itself to form a hollow sac. Mouth end and anus end. Which ever forms first helps classify the organism.
Gastrula - Blastula with a hollow sac that has formed.
Tissues
Cells of most animal are organized into structural and functional units called tissues. Tissues used to maintain homeostasis easier.
6 types. Connective tissue (Blood vessels), nervous tissue, epithelial tissue, skeletal muscle, cardiac muscle, and smooth muscle
5 Key innovations in animal evolution
Symmetry
Tissue allowing specialized structures and functions
Body cavity, made possible by 3 germ layers (Endoderm, mesoderm, ectoderm)
Patterns of embryonic development
Segmentation or repeated body units.
Symmetry
Most animals have radial or bilateral symmetry. (Sponges exception)
Radial symmetry (Pie/pizza) - Body parts arranged around central axis. Divided into two equal halves by any plane that passes through the center
Bilateral symmetry (humans, dogs) - Body has right and left halves that are mirror images. Only sagittal plane bisects the animal into two equal halves. Advantages over radial 1 Directional movement, Cephalization (evolution of a definite brain area)
Bilateral symmetry advantages
1 Directional movement
2 Cephalization - evolution of a definite brain area
Evolution of tissues allowed for specialized structures and funtions
Zygotes (fertilized eggs) are totipotent (Potential to form any cell type in body)
Cells specialized during embryo development, process irreversible (except sponges). All animals have distinct and well-defined tissues
Germ layers
Most have 3 germ layers- triploblastic
Ectoderm (body coverings and nervous system)
Mesoderm (skeleton and muscles)
Endoderm (digestive organs and intestines)
Triploblasts have bilateral symmetry.
Cnidarians are diploblastic, only endo and ectoderm.
Sponges lack germ layers
Body cavities
Acoelomates = no body cavity
Pseudocoelomates = body cavity between mesoderm and endoderm
Coelomates = Body cavity entirely within the mesoderm all deuterostomes have coeloms.
Use to be morph based phylogeny
Protostomes are variable
Circulatory systems
Coelomates developed a circulatory system that flows nutrients and removes wastes.
Open circulatory system - blood or similar fluid passes from vessels into sinuses, mixes with body fluids and reenters the vessels. Blood gets back to heart without vessels
Closed circulatory system - blood moves continuously through vessels that are separated from body fluids.
Two different patterns of development for bilaterians
Basic pattern of development - Mitotic cell divisions (cleavages) form a hollow ball of cells called the blastula. Blastula indents to form a two-layer-thick ball with blastopore (opening to outside) and archenteron (primitive body cavity)
Groups of bilaterians
Protostomes - Develop mouth first from or near blastopore. Anus develops either from blastopore or another region of embryo if present. (arthropods, mollusks)
Deuterostomes - Develops the anus first from the blastopore. Mouth develops later from another region of the embryo. (Vertebrates)
Segmentation 2 advantages
1 Allows for redundant organ systems in adults such as occurs in the annelids (earthworms)
2 Allows for more efficient and flexible movement because each segment can move independently.
Segmentation appeared several times in evolution of animals.
Worms, lobsters, fish and humans (backbone and muscles.)
Animal phylogeny
Traditional looked at body plan, morph, life cycle
New are molecular data.
Classification of animals
Multicellular animals are divided into distinct phyla. Animals are divided into two main branches
Parazoa - Sponges monophyletic
Eumetazoa = all other animals.
Eukarya -> Opsithoknotas -> Parazoa and Eumentazoa
Protostome division
Lophotrochozoans - Grow by gradual addition to the body mass. Have spiral cleavage
Ecdysozoans - Animals that molt. Includes arthropods and other phyla
Deuterostome division
Includes chordates and echinoderms (starfish).
Consists of fewer phyla and spp than protostomes. More uniform in many ways
Kingdom Animalia
Metazoa
divided into 2 branches
Parazoa - animals lacking tissues and definite symmetry
Eumetazoa - animals with a definite shape, symmetry, tissues and possibly organs
Phylum Parazoa
Sponges. 26,000 marine and 150 freshwater.
Among the most abundant animals in deep ocean.
Sexual and asexual, fragmentation. Coenocytes- flagellated sperm cells with collar and swim to egg to develop in mother or fertilized egg released and floats to new spot
Porifera characteristics
Sponges, lack symmetry. Various growth forms. Larval sponges free swimming. Adults attached and sessile. Cell types, truly multicellular. 3 functional layers in vase shaped body
3 layers of body wall of Porifera
1Outer epithelium - flattened cells with lots of pores for water movement through flagellated layers. Ostia comes in, osculum exits
2Mesohyl - middle, gelatinous matrix. Spicules needles of (calcium carbonate), Spongin (reinforcing tough protein fibers) both of skeleton.
3Lining of internal cavity. Choanocytes. Collared cells, flagellated to contribute to water circulation. Face of internal cavity. Engulf and digest food from passing water.
