Transcript sponges and nidarians ch 26

Bellwork
Plant or Animal?
• What is an animal?
• Backbone? Cell Wall? One Celled?
Chapter 26
Sponges and
Cnidarians
What is an animal?
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Heterotrophs
Multicellular
Eukaryotic
Do not have cell walls
Kingdom Animalia
Invertebrates
• Do not have a backbone
or vertebral column
• Size – from microscopic
dust mite to giant squid
(59 feet; almost a ton)
• Include over 95% of all
animal species
Invertebrates
• http://animals.nationalgeographic.com/anima
ls/invertebrates/giant-squid/
Vertebrates
• Represent the other 5 %
• Have a backbone or vertebral
column
• Include fishes, amphibians, reptiles,
birds, and mammals
How Animals Survive
• Feeding, respiration, circulation,
excretion, response, movement,
reproduction
• Have many different ways to carry out
these functions
• Maintain homeostasis – temperature, blood
sugar, heart rate, respiratory rate, etc…,
• Feedback loops involve feedback
inhibition – in which the product or
result of a process stops or limits the
process
Feeding
• Most do not absorb, but must eat or
ingest it
• Herbivores, Carnivores, Detritivores,
Filter feeders, Symbiotic Relationships
Respiration
• Whether on land or in the water, all
animals respire – take in Oxygen and
give off Carbon dioxide
• Some by diffusion
• Some complex circulatory system
organs and tissues
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Circulation
• Some rely on diffusion to transport
oxygen, nutrients, and waste
products… Works because they are
only a few cell layers thick
• Larger animals rely on circulatory
tissues, organs and systems to
circulate oxygen, nutrients, and
wastes
Excretion
• Ammonia primary waste product of
metabolism that contains Nitrogen
• Is poisonous
• Must eliminate ammonia or change it
to a less toxic substance to be removed
from the body
• Removing wastes maintains homeostasis
Response
• Responds to events in environment
using nerve cells
Sexual Reproduction
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By producing haploid gametes (egg and sperm.)
Helps create genetic diversity
Involves Crossing over
Improves species abilities to evolve when the
environment changes.
Asexual Reproduction
• Many invertebrates
reproduce asexually
• Offspring are
genetically identical to
parent
• Increases numbers
rapidly
Complex Animals
• Generally, the more complex, the more
highly evolved
• High levels of cell specialization
• High levels of internal body organization
• Bilateral symmetry
• A front end or head with sense organs
• A body cavity
Bilateral Symmetry
• Only one imaginary plane can divide the body into
two equal halves.
• They have left and right sides
• Front and back ends- Anterior/Posterior
• Upper and lower sidesDorsal/Ventral
Cephalization
• In animals with bilateral
symmetry
• Sense organs and nerve
cells at the front end of
the body
• Respond to the
environment more quickly
and in more complex ways
Radial Symmetry
• Every animal has body symmetry except for sponges =
Asymmetrical
• Radial Symmetry – have body parts that repeat around
the center of the body. Think of a bicycle tire in which any
number of imaginary planes can be drawn through the
center, each dividing the body into equal halves
Sponges
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Sponges
Simplest animals, least evolved
540 million years old
Most ancient animals
Most live in oceans
From arctic regions to tropical waters
Phylum – Porifera – meaning pore
bearers
Form and Function
• No mouth or gut
• No tissues or organ systems
• A few specialized cells
Body Plan
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Asymmetrical
No front or back end
Large cylindrical water pump
Choanocytes – use flagella to move a
steady current of water through the
sponge
• Water enters through pores and leaves
through the osculum – large hole at
top
Sponges
• Sponge with Dye
• World of Sponges (Show at end of ppt.)
• Freshwater Sponges (Show at end of ppt.)
• This movement of water
provides: feeding, respiration,
circulation, and excretion
• Have simple skeleton
• Harder sponges – skeleton
make of spicules – spikeshaped, made of chalk-like
calcium carbonate or glasslike
silica
• Spicules made by archaeocytes
– cells that move around
within the walls of the sponge
• Softer sponges have internal
skeleton made of spongin – flexible
protein fibers
Feeding
• Filter feeders
• Digestion takes place inside cells
• Food particles are trapped and
engulfed by choanocytes
Choanocytes
(a summary)
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Have flagella
Create current
Trap and engulf food particles
Transport partly digested food
particles to archaeocytes
Archaeocytes
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Make spicules
Move around
Complete digestion
Transport digested
particles
Respiration, Circulation,
Excretion
• Carried out by moving water
• Oxygen diffuses into cells
• Carbon dioxide, and Ammonia
diffuse out of the cells
Response
• No nervous system to respond to
changes in the environment
• For protection, some produce toxins
that are unpalatable or poisonous
• Spopnge Economy
• Sponge Harvesting
• 4 New Species of Sponges
Reproduction
• Sexually or Asexually
• Most sponges form egg and sperm by
meiosis
• Eggs fertilized inside the sponges body –
internal fertilization
• Sperm of one sponge are released and
carried by currents inside the body of
another sponge
• Archaeocytes carry the sperm to the egg
• After fertilization, zygote develops
into a larva
• Larva are motile and carried by
currents – until they attach to the sea
floor and begin to grow
Reproduction Asexual
• By budding or producing gemmules
• Budding – part of sponge breaks off,
settles to the sea floor, and begins to
grow
• Gemmules – produced in difficult
environmental conditions
• Gemmules are groups of aechaeocytes
surrounded by spicules
The gemmules are another means of surviving
adverse conditions, and germinate when
conditions improves. They are composed of a
mass of archaeocytes rich in food reserves, and in
fresh-water species possess a hard coat. Marine
gemmules develop external flagella at one pole
and after swimming for a time attach by the
opposite pole and develop
into young sponges.
• Gemmules can survive freezing
temperatures and drought
• When conditions become favorable,
the gemmule will grow into a new
sponge
Ecology of Sponges
• Provide habitats for snails, sea stars,
and shrimps… Commensalism
• Photosynthetic organisms provide food
and oxygen for the sponge, sponge
provides protection… Mutualism
• In deep waters, spicules act like a lens,
and focus sunlight to photosynthetic
organisms – This adaptation allows
sponges to live in a range of habitats
Cnidarians
Cnidarians
• Phylum Cnidaria
• Hydras, jellyfishes, sea anemones,
and corals
• Some live as individuals
• Some live in colonies of dozens or
thousands of connected individuals
• Cnidarians
• Cnidarians
• Cnidarians are soft-bodied, carnivorous, and
have stinging tentacles that surround the
mouth
• Have Radial symmetry and specialized
tissues
• Cnidocysts – stinging cells - along their
tentacles – used for defense and catching
prey
• Cnidocysts have nematocysts – poison filled
stinging structure that contains a tightly
coiled dart p.669
• Nematocysts
• Jellyfish
• Box Jelly
Form and Function
• Specialized tissues for feeding and
movement
Body Plan
• Have a life cycle that includes a polyp
and medusa
• Polyp – cylindrical, mouth points
upward surrounded by tentacles,
sessile
• Medusa – motile, mouth on bottom,
bell shaped body
• Internal space – gastrovascular cavity –
digestive chamber with only one
opening
a) Gastroderm – inner lining where
digestion takes place
b) Mesoglea –middle layer
c) Epidermis – outer layer of cells
Feeding
• Paralyzes prey, pulls it through its
mouth and into its gastrovascular cavity
• Extracellular digestion
• Absorbed by the gastroderm, where
digestion is completed
• Any materials that cannot be digested,
exit the mouth
Circulation, Respiration, and
Excretion
• Nutrients - transported by diffusion
• Respiration – diffusion
• Elimination - diffusion
Response
• Use specialized sensory cells –Nerve Net
• Nerve Net – loosely organized network of cells
that together allow cnidarians to detect
stimuli – touch
• Distributed uniformly
• Statocysts – sensory cells that help
determine the direction of gravity
• Ocelli – eyespot – made of cells that
detect light
Statocyst = Gravity
Movement
• Different cnidarians move in different
ways
• Sea anemones – hydrostatic skeleton
• Consists of a layer of circular muscles
and a layer of longitudinal muscles
that, together with the water in the
gastrovascular cavity, enable the
cnidarian to move
• Body becomes taller
• Muscles and Nerves
• Medusa – jet propulsion – water
comes in to and out of the bell
Reproduction
• Sexual and Asexual
• Polyps – asexually – budding
• Tiny Medusa – is produced asexually –
budding – Large Medusa reproduces
sexually Page 672
• External Fertilization – sexual
reproduction
• Most are either male or female
• Sea Anemone vs Jellyfish
• Lion's Mane Jelly
Ecology of Corals
• Distribution determined by
a) Temperature
b) Water depth
c) Light intensity
Symbiotic Relationship
With Algae
• Algae capture sunlight, recycle
nutrients, and help corals lay down
their Calcium carbonate skeletons.
• Provide as much as 60% of the
energy that corals need
• This allows corals to live in nutrient
poor waters
Human Activity and Corals
• Recreational divers break corals
• Silt and sediments from logging,
mining, and construction smother
corals
• Chemical fertilizers, insecticides, and
industrial pollutants poison corals
• Coral Bleaching – high water
temperatures kill algae - which will
lead to lack of oxygen and nutrients
• circulatory system
• pics cells