animelia. animalia: evolutionary origins animals are heterotrophs all animals are consumers, and...
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Animelia
Animalia: Evolutionary Origins
• Animals are heterotrophs• All animals are consumers, and some are
decomposers• The first animals are thought to be
descendants of protists• Chordates that possess a backbone are
called vertebrates; all other animals are invertebrates
What are the most ancient animals?What are the some recent to have evolved?
Review: The Linnaean System of Biological Classification
Domain……………………….Did
Kingdom……………………..King
Phylum……………………….Philip
Class……………..…………..Come
Order………………………….Over
Family………………………...For
Genus…………………………Great
Species……………………….Soup?
Animals: Embryo Development
• Embryonic cell layers generate all the different types of tissues found in adult bodies
• Protostomes and deuterostomes develop the digestive system in opposite directions
Animals: Symmetrical Bodies
• Most have symmetry• Radial symmetry
– divides like a pie getting identical pieces
• Bilateral symmetry– divides the body
into two halves that mirror each other
Animals: Organ Systems
• Most animals have organ systems
• Organs allow animals to function more efficiently
• Two or more organs working together form an organ system
Animals: Segmentation Enabled Division of Labor among Body Parts• Segmentation allows division of labor among body
parts • Appendages are specialized body parts that arise
from body segments and allow for evolutionary adaptations
Animals: Complexity of Body Cavities
• Body cavities allow an animal’s internal organs to grow freely and function independently
• Most body cavities also provide padding and protection for organs
• There are three types of body cavities found in animals:– Acoelomate– Pseudocoelomate– Coelomate
Shared Derived Traits of all Animals
• Animal cells lack a cell wall and are instead attached to an extracellular matrix
• Velcro-like patches of proteins called cell junctions allow animal cells to attach to each other
The First Invertebrates:Sponges, Jellyfish, and Relatives
Sponges• Acoelomates• Shared derived traits:
– Filter feed– No symmetry – No tissue– have “pores”
Do Sponges have Skeletons?!
All animals from now on have true tissues
Phylum Cnidaria• Cnidarians include
corals, sea anemones, and jellyfish
• Acoelomates
• Shared derived traits:– Radial symmetry– A nerve network– A lack of organs and
organ systems– Cnidocytes, stinging
cells– A mouth but no anus
11,000 species
All animals from now on have bilateral symmetry
The Protostomes
The Protostomes• Protostomes comprise the largest branch of the
evolutionary tree and range in size from microscopic to rotifers to the colossal squid
• Protostomes share the following characteristics– Development of the mouth from the embryonic
blastopore– Cephalization-has a head
Phylum Rotifera• Rotifers are
important aquatic decomposers
• Shared derived traits:– Cuticle– Corona
• Scanning electron micrographs showing morphological variation of bdelloid rotifers and their jaws.
Phylum Platyhelminthes:Flatworms and Flukes
• Flatworms can be free living or parasitic and lack respiratory and circulatory systems
• Acoelomates• Often parasites• Shared derived
traits:• 2 to 3 cells thick• a “mouth” but no
anus!
Tapeworms!
24 feet long tapeworm out of a mans intestine!
Tapeworms!
Liver fluke!
Phylum Nematoda
• Also known as roundworms
• Examples: hookworms, pinworms
• Pseudocoelom• Shared derived traits
– round worms– full digestive tract
(mouth, intestine, anus)
Hookworms!!
All Animals from now on have a True Coelom
• Coelom – A fluid-filled cavity surrounding the digestive
tract and other internal organs
15,000 species
Annelida
Annelids: Segmented Bodies
• Full digestive tract, circulatory system
• Shared derived traits– Segmentation
allows division of labor among body parts
112,000 species
Mollusca
Phylum Mollusca
• The Mollusca is one of the most diverse phylum of animals and includes shellfish, snails, slugs, squid, and octopi
• Shared derived traits:– A muscular foot at the
base of the body– A compact grouping of
internal organs called the visceral mass
– A mantle enclosing the body cavity and the visceral mass
Mollusks Constitute the Largest Marine Phylum
• Bivalves hinged shell• Most gastropods have a spiral shell• Cephalopods thought to be the smartest invertebrates
Phylum Mollusca
Not all Mollusca have shells