General Characteristics
1. multicellular
2. eukaryotic
-- have a nucleus
-- DNA (in the form of chromosomes) inside the nucleus
3. have no cell wall (= protein structural molecule rather than cellulose)
4. aerobic (= must have oxygen)
5. heterotrophic (= ingest food)
6. large (compared to bacteria)
- multicellular - heterothrophic - movable
- no symmetry, radial symmetry, bilateral symmetry
- no body cavity, false body cavity (pseudoceolomate), true body cavity (coelomate)
- gut type
- segmentation
- deuterostomes (blastopore develops into anus), protostomes (blastopore dev. into a mouth)
Movement to land
-- Animals invaded land about 410 mya -- insects and amphibians (after fungi and plants)
• Early animal forms lived in the oceans
1. no problem with dehydration
2. no problem with rapid temperature changes
3. no problem with extreme temperatures (narrower temp. range in the oceans)
• Problems which needed to be overcome- (e.g., amphibians)
1. keeping membranes moist for gas exchange - (must keep skin moist) 2. supporting locomotion without buoyancy of water - (clumsy walkers) 3. transporting water in the body - (circulatory system) 4. conserving water in the body - (live near water) 5. reproduction in a dry environment - (reproduce in water -- not internal) 6. development of the early embryo - (no amniotic sac -- as in higher vertebrates) 7. surviving rapid environmental changes - (dormant, dig down or hide)
Evolutionary time table 1. 600 mya --------------------------------------------------------------------------
Age of invertebrates Age of Algae Cambrian Explosion
(Cambrian Explosion: The Cambrian explosion or Cambrian radiation was the relatively rapid appearance, over a period of many million years, of most major Phyla around , as found in the fossil record.)
2. 500 mya --------------------------------------------------------------------------
First Fishes (jawless) First plant fossils
Age of Fishes First Amphibians & first Insects
3. 400 mya --------------------------------------------------------------------------
Age of amphibians Age of coal forming forests
4. 300 mya --------------------------------------------------------------------------
Amphibians decline
First Reptiles
First Dinosaurs First Mammals Age of gymnosperms
5. 200 mya --------------------------------------------------------------------------
Age of Dinosaurs
First Birds First flowering plants
First Placental Mammals
6. 100 mya -------------------------------------------------------------------------- Age of Angiosperms
7. 66 mya --------------------------------------------------------------------------
Dinosaurs become extinct
Age of Mammals (and Insects) (All modern orders of mammals represented,
including rodent-like Primates)
8. 30 mya --------------------------------------------------------------------------
First monkey-like Primates
9. 15 mya --------------------------------------------------------------------------
First Hominoids (Apes)
10. 4 mya --------------------------------------------------------------------------
First Hominids (Chimpanzee and human evolutionary lines separate)
13. 0.2 mya -------------------------------------------------------------------------- Homosapiens Age of Human civilization Destruction of natural habitats (e.g., tropical rain forest)
by humans accelerates extinctions
Classification
-- Zoologists divide the animal kingdom into about 35 phyla. (Below are 9.) The tree has changed major ways "lately" -- and some characteristics, like "body cavites" are no longer as important.
The Animalia evolutionary tree has changed major ways "lately" -- and some characteristics, like "body cavites" (acoelomates, pseudocoelomates, coelomates) are no longer as important.
Trunk and branches?
--- The trunk of the animal evolutionary tree
--- The “left” branch of the animal evolutionary tree (Protostome animals)
---The “right” branch of the animal evolutionary tree (Deuterostome animals)
• The trunk of the animal evolutionary tree
- evolutionary step : Multicellular -- but no true tissue, and no symmetry
-- previous: unicellular
Phylum Porifera (Sponges)
1. Asymmetry
2. No true tissue (digestion within cells)
3. No body cavity
-- Almost all are sessile
All other animal groups have true tissue and symmetry
- evolutionary step : Radial Symmetry (no head)
-- previous: asymmetry (= no symmetry)
Phylum Cnidaria (Hydras, jellyfishes, SeaAnemones and Corals)
1. Radial symmetry
2. True tissue (Diploblastic)
3. No body cavity
1. Bilateral symmetry
2. True tissue (Triploblastic)
3. No body cavity (Acoelomate) -- Have an incomplete digetsive tract (no anus)
Parasites
def. Parasites: Ecological relationship between two organisms where only one organism benefits, by deriving nourishment from the other, without killing it (at least not immediately) but usually doing harm to it.
def. Parasites: Ecological relationship between two organisms where only one organism benefits, by deriving nourishment from the other, without killing it (at least not immediately) but usually doing harm to it.
Class Horse-shoe crabs (Merostomata) Class Crustaceans (Crustacea) lobsters, crabs, crafish, shrimp Class Arachnids (Arachnida) spiders, scorpions, ticks, mites Class Insects (Insects, or Hexapoda) beetles, butterflies, bees, flies Class Millipeds (Diplopoda) Class Centipeds (Chilopoda)
• The “right” branch of the animal evolutionary tree
Animals. Bozeman.
(Source: Dr. Nilsson's old lecture notes. Permission given in 2001 by McGraw-Hills then sales representative, Don Grainger, to use the picture online on lecture notes.)
Phylum Porifera (Sponges)
Phylum Cnidaria (Hydras, jellyfishes, SeaAnemones and Corals)
Phylum Platyhelminthes (Flatworms -- flukes, tapeworms)
Phylum Nematoda (Roundworms -- e.g., Ascaris, Trichinella)
Phylum Annelida (Segmented Worms -- earthworms, leeches)
Phylum Arthropoda (Arthropods, Jointed-legged animals)
Phylum Echinodermata (Echinoderms -- sea stars, sea urchins, sand dollars, sea cucumbers)
Phylum Chordata ("Vertebrates")
