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Lecture 11

BIOL 111 Lecture Notes - Lecture 11: Blood Sugar, Ecolo, Cuticle


Department
Biology
Course Code
BIOL 111
Professor
Heather Roffey
Lecture
11

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BIOL 111 – Organismal Biology
LECTURE 11 – INTRODUCTIONS TO ANIMALS; SPONGES
Animal Characteristics
1. eukaryotic
“true” nucleus
DNA is linear as opposed to circular
membrane-bound organelles (e.g. mitochondria, Golgi apparatus, endoplasmic
reticulum)
in the domain Eukarya
2. heterotrophic
“different feeding”
use organic materials as energy and carbon sources
bring food in by ingestion (as opposed to phagocytosis or absorption)
filter feeders – aquatic, usually sessile organisms
predators – kill another animal to eat it
herbivores – eat plants or algae
parasites – feed off of living organisms
detritivores – dirt-eaters (e.g. earthworm, sea cucumber)
3. no cell wall
how do animals support themselves? (see next section)
4. motile at a some life stage
5. multicellular
disadvantages:
olots of cell division
oenergetically costly
olonger time to maturity
advantages:
omore specialization
omore diverse functions
ocells can remain small even in large organisms
omaterials can diffuse throughout whole cell more quickly
6. have tissue
tissue – groups of structurally similar cells that function together
tissues can functions together as organs to complete more complex tasks
nervous – conducts impulses (e.g. tissue that makes up the human brain and nerves)
epithelial used for covering and protection (e.g. tissue that lines human digestive
tract)
connective living cells in a non-living matrix (blood is connective blood cells
(living) flow through plasma (non-living matrix))
muscular – contract and lengthen to control movement and support
a given organ may be comprised of some or all of these tissue types (e.g. human
stomach contains all four)
7. life cycle is mostly diploid
animals’ life cycles are much simpler
fertilization – two haploid cells join to make diploid
meiosis – diploid cell divides to haploid
NONE OF THESE CHARACTERISTICS ARE UNIQUE TO ANIMALS!
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BIOL 111 – Organismal Biology
Types of Structural Support
1. hydrostatic skeleton
fluid-filled cavity acted on by muscles
e.g. earthworms, jellyfish
2. exoskeleton
external skeleton
non-living covering, but produced by living
made of proteins or calcium carbonate (in some aquatic animals)
does not grow with animal
ecdysozoans – molting animals – they must shed their exoskeleton to grow
e.g. green dragonfly
3. endoskeleton
internal support
in vertebrates, endoskeleton is made of living tissue (i.e. bones)
in some invertebrates, endoskeleton is non-living (i.e. CaCO3)
Kingdom Animalia
has about 35 major groups (phyla)
about 1.7 million species have already been classified, but there is an estimate 10 million
species
97% of animals are invertebrates
all animals are monophylogenetic – they all come from one common ancestor
common ancestor probably a colonial choanoflagellate
oindependent cells that live on a stalk
owere marine
oeach cell has a “collar cell” and flagellum
choano” = collar
used flagella to help feed
first animals were marine and appeared 1.2 BYA to 700 MYA
animal diversification
ooccurred at the Cambrian explosion
543-488 MYA
rapid diversification
most present day phyla and more
many new phyla formed
Sponges (Porifera)
there are about 8000 species
most sponges are marine
size ranges from 2mm to 2 m
sponges are sessile as adults but motile as larvae
sponge morphology is high variable
sponges are filter feeder
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BIOL 111 – Organismal Biology
othey acquire nutrients and energy by filtering particles from water
Sponge Anatomy and Feeding
porifera = “pore bearer”
ostia (or incurrent pores) absorb water and food (i.e. phytoplankton, cyanobacteria,
unicellular green algae, diatoms, etc.)
spongocoel – internal cavity
ocoel” = cavity
osculum (or excurrent pore) – expels water and wastes
wall of the sponge is made of 4 types of cells embedded in a jelly matrix, called mesohyl
(this is not considered real tissue/organ)
oonly phylum of animals that does no have tissues (cells do not work together)
choanocytes are cells that line the wall of the spongocoel, and beat their flagella to create
a water current, which brings water in through the ostia. Flagella then catch nutrients
amoebocytes (appear and move like amoeba) are motile cells inside the mesohyl, which
receive the nutrients from the choanocytes and distribute them throughout the organism.
They also produce eggs and sperm
epidermal cells make up the external wall of the sponge
pore cells make up the ostia and osculum
spicules are non-living structures in the mesohyl that provide support and skeleton. They
can be made of silicon dioxide (SiO2 = glass) (i.e. glass sponges) or calcium carbonate
(CaCO3 = limestone) (i.e. calcareous sponges)
some sponge, instead of spicules have a more flexible skeleton of spongin, which is a
protein (e.g. bath sponges)
when choanocytes bring in food, the food gets trapped in the collar cells and travel to the
main cell body by mucous and engulfed by phagocytosis. Then an amoebocyte comes over
and takes the food. Digestion then occurs intracellularly in the amoebocytes.
osponges are the only animals that undergo intracellular digestion
Sponge Reproduction
sponges reproduce asexually (by fragmentation or buds), or sexually by releasing
gametes into the water
asexual reproduction
ofragmentation
not self-induced if sponge is divided by a wave or predator,
each segment will become a new organism
obudding
clone of parent grows off of parent and then falls off
sexual reproduction
ohermaphroditic
does not imply self fertilization
sperm and eggs develop inside single cells
broadcast sperm – sperm is sent out
a sponge filters in different sperm through its ostia, its egg is
fertilized and develops in the mesohyl
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