Post on 18-Dec-2015
Invertebrates
Chapter 29 and 30
Sponges, Cnidarians, Flatworms, Roundworms, mollusks, annelids
Animal Kingdom Characteristics
- multicellular
- eukaryotic
- heterotrophs
- movement
- tissues
Body Plans
- Bilateral Symmetry- equal halves in one direction
Radial Symmetry
• - 360 degrees; equal halves
- Asymmetry- cannot cut in equal halves
Body Development
- Ectoderm- outside body layer- skin and hair
- Endoderm- inside body layer- digestive tract
- Mesoderm-
middle layer- muscles, blood and organs
- Types of Body Cavities:
1. Coelom- true body cavity
- surrounded by mesoderm
-2. Pseudocoelom- false cavity
- between mesoderm and endoderm
3. Acoelomate
No body cavity.
Let’s Review.
What type of symmetry is this?
What type of symmetry?
Symmetry?
- Vertebrates- animals with backbones
- fish, amphibians, reptiles, birds, and mammals
- Invertebrates- animals without backbones
- sponges, cnidarians, mollusks, worms, echinoderms, arthropods
Sponges: Phylum PoriferaAsymmetrical – no symmetryNo tissues or organs (cells work together to perform a specific function2 body layers: endo-, ecto-Sessile – do not moveVariety of shapes and colorsAcoelemate – no body cavity
Digestion of sponges
Sponges are consumers
Feed on bacteria, algae, protozoans (filter feeders)
Sponge digestion continued:
Reproduction
Either sexual or asexual
Asexual- fragmentation- each piece of sponge will grow into a complete new sponge
Sexual- hermaphrodite- produce both eggs and sperm- release into water at different times-sperm from one enters pores of other to fertilize eggs- External fertilization
Reproduction continued
Produces a zygote- free swimming larvae for a short time- attaches to surface- new sponge
Cnidarians- the stingersCoral
Characteristics of Cnidarians
Two Types: Polyp – sessile, tube-like
with tentacles ex. Coarl, sea anemone
Medusa – free swimming, umbrella shaped
Jellyfish
Has tissues – ecto-, endo-Nematocysts – stinging cells on tentaclesRadial symmetryacoelamate
B
How Cnidarians Get O2?
Diffusion
Have nervous tissue.
Reproduction
Asexual- budding- small extensions of body grow and then breaks away from parent
Sexual-some species are hermaphrodites Others, female releases egg and male releases
sperm into water- External fertilization
Jelly fish
Sea anemone
Coral reef
Coral reefs
Structure
See diagram – oldest part is deeper. Newest is toward the top.
Live symbiotically with unicellular yellow brown algae- zooxanthellae
Benefit of Symbiotic Relationship:Coral gets:
food
(coral can also capture food with tentacles)
Algae gets:
Protection and access to sunlight
Coral Bleaching
When coral ejects it’s algae- coral turns white
Coral doesn’t get enough food- dies
Coral bleaching due to:
Diseases
Increased Ultra violet radiation
Sedimentation
Pollution
Increased water temperatures
Direct destruction by humans- anchors, touching while diving
Bleached coral
Flatworms
Acoelomate
Bilateral symmetry
Platyhelminthes – flatworms
Characteristics of flatworms:
Can be parasitic, or free living
1 body opening
Hermaphrodites or asexual reproduction by regeneration: breaking in 2, and each becomes a new organism
Get O2 through skin- diffusion
Tapeworm
Body Two parts: Scolex – head Proglottids – body
sections
Attach to inside of intestinesParasiteEx. Beef tapeworm: become infected by eating raw beef.
Getting Beef tapeworm:
Blood fluke - causes Schitomiasis
Planeria
Eyespots- light
Pharynx- extends like a straw, releases enzymes- breaks down food , sucks it up
Sensory pits on side of head, detect food, chemicals, and movement
Ability to regenerate
planeria
29-4 Roundworms
Pseudocoelum
Tube within a tube body
2 body openings
Move in a side to side manner
parasites
Ex. Ascaris - hookworm
Carried through human waste to soilIf ingested eggs enter large intestine – becomes larvaeLarvae bore through blood vesselsBack to the intestine to mate
Ascaris in pig intestine
Trichinella – pork roundworm
Causes Trichinosis
Eating improperly cooked pork
Mollusks and Annelids
Chapter 30
Mollusks
Characteristics Invertebrates Larval stage Marine, freshwater,
terristrial coelomates
Mollusks have 3 parts to body:
Visceral mass – contains organs
Mantle – tissue around visceral mass (secretes a shell)
Foot - locomotion
Other Mollusk characteristics:
Exoskeleton Sometimes called a
valve
Outer skeleton
•Radula
(not in bivalves)
Tongue-like structure
Organ systems of mollusks:
Excretory – get rid of waste:
Open Circulatory System –heart pumps fluid through a series of vessels out into body cavity
Organ Systems of Mollusks
Reproduction – most have separate sexes, external fertilization
Respiration – use gills
30-2 Groups of Mollusks
Bivalves – “two valves”
Valves held together by strong muscles
No radula
Filter feeders
Examples: clams, oysters, scallops
Bivalve Photos
Gastropods
Examples are snails and slugs
Single shell or none
Use radula to scrape food off of rocks etc
Land snails – hermaphrodites, aquatic snails – separate sexes
Herbivores
Gills or lungs?
Cephalopods – “head footed”
Examples: squid, octopusLarge head with tentaclesEyesMarine predators (consumers)Ink sac – for protectionInternal shell – penBrain present – complexSkin can change colorgills
Phylum Annelida
Segmented worms
Examples: earthworms, leeches, sandworms
Segmented body
Coelum
Bilateral symmetry
Abundant in all habitats
Organ Systems in Segmented Worms
Closed circulatory system
Excretory system – nephridia
Breath through skin
Bristles – setae
Reproduction – hermaphrodites
Digestion of Earthworm
Pathway of food: Pharynx – soil enters Esophagus - Crop-storage Gizzard- muscular for
grinding soil Intestines – absorption anus
Groups of Annelids
Marine segmented worms
Leeches