Chapter 18-19 Flashcards Preview

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Flashcards in Chapter 18-19 Deck (76)
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1

what are animals

multicellular, heterotrophic eukaryotes that obtain nutrients by ingestion.

2

animal cells

-distinctive structures and specializations
-lack cell walls
-held together by extracellular structural proteins

3

lineage that gave rise to animals

-diverged from flagellated unikont ancestor about 770 million years ago

4

when did animal diversification accelerate?

535-525 million years ago during the Cambrian period. Cambrian explosion.

5

vertebrates

-only 1 phylum
-animals with a backbone

6

invertebrates

-around 96% of all animals
-animals that lack a backbone

7

Animal body plans vary in

-symmetry
-presence of true tissues
-number of embryonic layers
-presence of a body cavity
-details of their embryonic development

8

eumetazoa clade

"true animals." animals with tissues

9

bilateria clade

branch of eumetazoa. animals with bilateral symmetry
-three main lineages: Lophotrochozoa, Ecdysozoa, Deuterostomia

10

Lophotrochozoa

flatworms, molluscs, annelids

11

Ecdysozoa

nematodes and arthropods
-have external skeletons that must be shed for the animal to grow

12

Deuterostomia

echinoderms and chordates

13

sponges

-are simple animals
-do not have true tissues
-usually lack body symmetry
-are usually marine, although some are found in fresh water.

14

choanocytes

flagellated "collar" cells that make up the inner cell layer in sponges that help to sweep water through the sponge's body.

15

suspension feeders

animals that collect food particles from water passed through some type of food-trapping equipment
-sponges

16

cnidarians

-branch of eumetazoans
-hydras, sea anemones, corals, and jellies
-characterized by raidal symmetry and bodies arising from only 2 tissue layers.

17

polyp

-body form of cnidarians
-hydras and sea anemones have cylindrical body with tentacles projecting rom one end

18

medusa

-body form of cnidarians
-marine jelly
-move freely about in the water

19

cnidocytes

stinging cells of Phylum Cnidaria.
-function in defense and in capturing prey

20

flatworms/phylum platyhelminthes

-belong to lophotrochozoan
-bilateral symmetry and three tissue layers
-three main groups: free-living flatworms, flukes, tapeworms

21

flukes

live as parasites in other animals

22

tape worms

parasitic group of flatworms. inhabit the digestive tracts of vertebrates

23

roundworms/nematodes

-bilateral symmetry
-three tissue layers
-have a fluid-filled body cavity
-a digestive tract with 2 openings

24

molluscs

snails, slugs, oysters, clams, octopuses, and squids
-soft-bodied animals, but most protected by a hard shell
-a muscular foot, which functions in locomotion,
-a visceral mass containing most of the internal organs,
-a mantle, which may secrete a shell that encloses the visceral mass
-a circulatory system.

25

gastropods

largest group of molluscs
-only molluscs that live on land
-protected by a single, spiral shell into which the animal can retreat when threatened

26

bivalves

group of molluscs
-clams, oysters, mussels, and scallops
-shells divided into two halves that are hinged together
-most suspension feeders

27

cephalopods

group of molluscs
-adapted to lifestyle of fast, agile predators

28

segmentation

the subdivision of the body along the length into a series of repeated parts

29

annelids

segmented worms
-clades errantians and sedentarians
-segmentation, the subdivision of the body along its length into -a series of repeated parts,
-a nervous system, and
-a closed circulatory system in which blood remains enclosed in vessels throughout the body.

30

erratians

-clade of annelids
-marine and may have an active, mobile lifestyle