Flashcards in EHOF- The Rise of Animal Diversity Deck (84)
What are animals?
-Heterotrophs that ingest their food
-Multicellular eukaryotes with cells that have no cell walls
What two tissues are unique to animals?
Nervous and muscle tissue
What is the digestive tract?
Most with a mouth at one end and an anus at the other- efficient eating machines
What are larvae?
Are sexually immature and their morphology is different from adults; they eventually undergo metamorphosis
What are the early diverging animal groups?
Sponges(Phylum Porifera) and jellyfish and sea anenmones(Phylum Cnidaria)
What are sponges?
-Unlike all mammals sponges like true tissues
-Choanocytes, Flagellated collar cells
-Amoebocytes contribute to digestion and structure
What are hermaphrodites?
Each individual function is both male and female. Sponges are these
What are cnidarians?
-Simple, diploblastic, radial body plan
-Eumetazoans with true tissues
-First since muscles and nerves
What are the basic body plans of cnidarians?
Polyps and medusas
How do cnidarians get food?
They use their tentacles with cnidocytes to capture prey Nematocysts are specialized organelles within cnidocytes that eject a stinging thread
What occurred during the Paleozoic era?
The Cambrian explosion
-The first fossil appearance of many groups of extant animals or their relatives
-The first bilaterians- Animals with bilateral symmetry (head and tail)
What are the three hypotheses for the Ediacaran lifeforms?
1. Predator prey arms race
2.Increased atmospheric oxygen may have favoured more active bilaterians with high metabolic rates
3.Origin of Hox genes which are developmental genes that program animal structure and body plan
What are the two types of symmetry?
What are the different germ layers?
Ectoderm, endoderm and mesoderm
What is the fluid filled body cavity in animals?
The coelom which provides suspension and cushioning for organs and allows organs to grow independent of the body wall
What are the key points from the animals phylogeny?
-All animals share a common ancestor
-Sponges are basal animals
-Eumetazoa is a clade of animals with true tissues
-Most animal phyla belong to the clade Bilateria
-The animals are invertebrates
What are 2 examples of bilterian invertebrates?
Lophotrochozoans which have a lophofore(feeding structure) or go through a larval stage called trochophore larva and ecdysozoans which shed their exoskeletons through a process called ecdysis
What is the Phylum Rotifera?
-Tiny animals that inhabit freshwater, the ocean and damp soil
-Truly multicellular and have specialized organ systems
-Many asexual species
What is the Phylum Mollusca?
-Snails and slugs, oysters and clams, octopi and squid
-They are soft bodied animals but most are protected by a hard shell
What are the three main parts of molluscs?
Muscular foot, visceral mass, and mantle
What are bivalves?
-Molluscs that include many species of clams, oysters, mussels and scallops
-Have a shell divided into 2 halves
-Mantle cavity has gills for gas exchange
What are cephalopods?
-Carnivores with beak like Jaws surrounded by tentacles of the modified foot
-Only molluscs with a closed circulatory system
-Well developed nervous system with a complex brain capable of learning
What is the Phylum Platyhelminthes?
Flatworms That are marine, freshwater and damp terrestrial habitats as well as parasites
What are trematodes?
They can parasitize humans can spend part of their lives in snail hosts
What is special about Phylum Annelida?
Have bodies composed of a series of fuse rings
What are leeches?
Predators of invertebrates and bloodsucking parasites. There are aquatic and terrestrial leeches and he secrete anti-coagulant called hirudin
What are ecdysozoans?
They are covered by a topcoat called a cuticle and the cuticle is shared or melted through a process called ecdysis
What is phylum arthropoda?
-The diversity and success of arthropods is attributed to segmentation, hard exoskeleton enjoined appendages and flights in insects
-Two out of every three known species of animals are arthropods
What are trilobites?
We arthropod show little variation from segment to segment