Chapter 24 Terms
Section 1
Invertebrates- animals w/o a backbone
exoskeleton – hard, waxy covering on outside of the body that
provides a framework for support
Vertebrates-animals w/a backbone
endoskeleton – support framework housed within the body
Animal Cells vs Plant Cells- plant cells have a cell wall making
them rigid – animal cells do not have a cell wall
Hermaphrodite- produce both sperm and eggs in the same body
Zygote-the cell resulting from the union of a male and female
gamete, until it divides; the fertilized ovum.
Fertilization-union of gametes
Internal Fertilization- Gametes unite inside the body
External Fertilization- Gametes unite outside the body
Blastula-single layer of cells surrounding a fluid-filled space and
is formed early in the development of an animal embryo
Gastrula – structure made up of 2 layers of cells early in the
development of an animal embryo
Endoderm – inner layer of skin digestive organs & digestive tract
Ectoderm – outer layer of skin nervous tissue & skin
Mesoderm – middle layer of skin muscles, circulatory–respiratoryexcretory system
Section 2
Symmetry – refers to a balance in proportions of an object or
organism
Radial symmetry – adaptation that enables the animal to detect &
capture prey coming toward it from any direction
Bilateral symmetry – can be divided down it’s length into similar
right and left halves that form mirror images of one another
Asymmetry – animal that’s irregular in shape
Cephal- combining form meaning head
-itis - combining form inflammation
Anterior – head end
posterior – tail end
Cephalization- tendency to concentrate nervous tissue and sensory
organs at the anterior end
dorsal – backbone side
ventral – belly side
coelom – body cavity completely surrounded by mesoderm
pseudocoelom – fluid filled body cavity partly lined with mesoderm
aceolomate – animals with three cell layers with a digestive tract
but no body cavities
Protostome- animal with a mouth that develops from the opening
of the gastrula -simple animals, earthworms, insects
Deuterostome – animal in which the anus develops from the
opening in the gastrula -complex animals, fishes, birds, humans
Segmentation- the division of bodies or body plans into a series
of semi-repetitive segments
Section 3 Sponges & Cnidarians
Sponges
OsculumCollar CellsSpiculesPoreArcheocyteLarva(e) Filter feederInternal FertilizationNo tissuesAsymmetricalCnidarians
Have tissuesRadial SymmetryCnidocytes- cnidarian stinging cells
Nematocyst- tube, poison, & barbs
Gastrovascular cavityTentaclesMouth/anusNerve netPolypMedusa-