Bio Ch.30-32 Flashcards
What happens in sexual reproduction?
Sperm and eggs unite to form a zygote.
The zygote undergoes cleavage.
Characteristics common to most animals.
- Eukaryotic
- multicellular heterotrophs
- a diverse body plan
- capable of locomotion some time during their life cycle
Advantages of life in the ocean.
- stable temperature
- provides buoyancy
- more readily available food
Disadvantage of life in water
Currents and water movements.
Disadvantages of living in fresh water
Less constant environment, with less food.
Animals must osmoregulate.
Disadvantages of living on land.
Animals must have adaptations that protect them from dying out and temperature changes, also to protect their gametes and embryos.
What is cephalization?
Development of a head, evolved with bilateral symmetry.
What happened during the Cambrian radiation ?
New animal body plans rapidly evolved among class already existing.
Biologist hypothesize that cnidarians and ctenophores are closely related because they share what?
Radial symmetry
This gives rise to the body covering and nervous system.
Ectoderm
Describe the endoderm.
Lines the gut and other digestive organs.
Acoelomate
No body cavity
Pseudocoelomate
Body cavity not completely lined with mesoderm
A body cavity completely line with the mesoderm
Coelom
Name the two major branches of bilateral animals.
Protostomes and deuterostomes
What kind of cleavage do protostomes undergo?
Spiral. ( early cell divisions are diagonal to the polar axis)
-determinate cleavage
What kind of cleavage do deuterostomes undergo?
- Radial cleavage (cell divisions are either parallel or at right angles to the polar axis.
- indeterminate cleavage
Protostomes are divided into which 2 major clades?
Lophotrochozoa and ecydsozoa.
Give examples of Lophotrochozoa.
Flatworms, ribbon worms, mollusks, annelids, Rotifers.
Give examples of ecydsozoa.
(Animals that molt)
-nematodes and arthropods
Phylum Porifera
Consist of sponges, animals characterized by flagellate collar cells.
Phylum Cnidaria
- Characterized by radial symmetry
- Two tissue layers
- Cnidocytes(cells that contain stinging organelles)
Hermaphrodite
Can produce both egg and sperm
True coelom
Fluid-filled body cavity completely lined by a mesoderm
- Enclosed compartment of fluid under pressure.
- A Space in which internal organs can develop.
Coelom
Examples of Lophotrochozoa
Nemerteans, mollusks, annelids, Rotifers
Examples of EcdysoZoa
Roundworms , arthropods
What group do protostomes belong to ?
Monophyletic
This phylum includes, clams, oysters, snails, slugs, large invertebrates etc
Phylum mollusca
Largest group of mollusks
Gastropoda
Major classes of phylum mollusca
Polyplacophora, Gastropoda , bivalvia, Cephalopoda
Example and characteristics of polyplacophora
Chitons
- marine animals with shell
- broad foot used for locomotion
Example and characteristics of Gastropoda
Snails, slugs
- marine, freshwater or terrestrial
- coiled shell
- well developed head with tentacles and eyes
Example and characteristics of bivalvia
- clams, oyster, mussel
- marine or freshwater
- suspension feeders
Example and characteristics of cephalopods
- squids, octopods
- marine , predatory, well developed eyes
Centipedes and millipedes belong to what phylum?
Myriapoda
Lobsters, crabs, shrimp, etc belong to what phylum ?
Crustacea
Insects belong to what phylum ?
Hexapoda
Mollusks are
- Soft bodied
- have an open circulatory system( with an exception of cephalopods)
Nematodes have a
Pseudocoelom
Characteristics of arthproda
Paired jointed appendages
Exoskeleton made of chitin
Molting
Deuterostomes are divided into what two phylums?
Echinoderms and chordates
Example of echinoderm
Sea star, sea urchin , sand dollar
example of chordates
Humans, vertebrates
An acorn worm is
A hemichordate(animals that live buried in sand or mud)
Main classes of Echinoderms
Asteroidea - sea stars
Ophiuroidea - brittle stars
Echinoidea- sea urchin, sand dollar
Holothuroidea- sea cucumbers
Most unique derived characteristics of echinoderm
- Water vascular system
- endoskeleton
- well developed coelom
- tube feet
At some time in its life, a chordate has
- a notochord
- a dorsal, tubular nerve cord
- post anal tail
- an endostyle
Name two main branches of protostomes.
Lophotrochozoa and EcdysoZoa
