week 8a

Question 1

what did animals probably arose from

Answer 1

a protist similar to the choanoflagellates

Question 2

what type of ancestor did animals evolve from

Answer 2

a choanoflagellate-like ancestor

Question 3

what is the closest living relative of animals

Answer 3

choanoflagellates

Question 4

what type of organisms are choanoflagellates

Answer 4

single-celled protists

Question 5

what structures are found on choanoflagellates

Answer 5

a single flagellum surrounded by a collar of cytoplasmic tentacles

Question 6

are all choanflagellates single-celled

Answer 6

no. some are colonial

Question 7

what evolutionary trait is suggested by some colonial choanoflagellates

Answer 7

some cells may have taken on specialized functions

Question 8

what animals cell type do choanoflagellates resemble

Answer 8

sponge choanocytes

Question 9

what are animals in terms of cell type and organization

Answer 9

multicellular eukaryotes

Question 10

do animal cells have cell walls

Answer 10

no, animals lack cell walls

Question 11

how do animals obtain energy

Answer 11

they are heterotrophs (consume other organisms for energy)

Question 12

are animals always motile

Answer 12

they are motile at some time in their lives

Question 13

how do animals reproduce

Answer 13

sexually or asexually

Question 14

what provides structural support in animals

Answer 14

an extensive extracellular matrix

Question 15

what is the function of unique cell junctions in animals

Answer 15

they hold cells in place and faciliate communication among them

Question 16

what are the three types of cell junctions in animals

Answer 16

anchoring junctions, tight junctions, and gap junctions

Question 17

what type of nutrition do all animals use

Answer 17

all animals are heterotrophs - eat other organisms or their products

Question 18

what is suspension feeding

Answer 18

filtering particles from surrounding water

Question 19

what is bulk feeding

Answer 19

eating large pieces of food

Question 20

what is fluid feeding

Answer 20

sucking sap or animal body fluids

Question 21

what types of cells are typically organized into tissues in most animals

Answer 21

muscle and nerve cells

Question 22

what tissue type is unique to animals

Answer 22

muscle tissue

Question 23

why do most animals need to be capable of locomotion

Answer 23

for food acquisition, escaping predators, and finding mates

Question 24

what systems coordinate movement in animsl

Answer 24

specialzied sensory structures and a nervous system

Question 25

how do sessile species like barnacles manage movement

Answer 25

they have moving appendages or a swimming larval stage

Question 26

how do nearly all animals reproduce

Answer 26

sexually

Question 27

what unites during sexual reproduction to form a zygote

Answer 27

a small, mobile sperm and a large egg

Question 28

what type of fertilization is common in terrestrial species

Answer 28

internal fertilization

Question 29

what type of fertilization is common in aquatic species

Answer 29

external fertilization

Question 30

do some animals reproduce asexually

Answer 30

yes

Question 31

what is metamorphosis in animals

Answer 31

a developmental change from a juvenile to an adult form

Question 32

how does metamorphosis benefit animals

Answer 32

it reduces competition and faciliates dispersal

Question 33

when did multicellular animals first emerge

Answer 33

600M+ years ago, at the end of the Proerozoic eon

Question 34

what were the first animals

Answer 34

invertebrates

Question 35

what major event led to a sudden increase in animal diversity

Answer 35

the cambrian explosion (533-525 million years ago)

Question 36

when did the cambriam period occur

Answer 36

543-490 M years ago

Question 37

what was the climate like during the cambrian period

Answer 37

warm and wet with no ice at the poles

Question 38

what defines the cambrian period

Answer 38

the cambrian explosion - a rapid increase in animal diversity

Question 39

by the middle of the cambrian period, which types of animals had appeared

Answer 39

all major types of marine invertebrates, including echinoderms, arthopods, mollusks and chordates

Question 40

what is the burgess shale

Answer 40

a rock bed in the canadian rockies that preserved many cambrian fossils

Question 41

how did the burgess shale preserve soft tissues

Answer 41

an underwater mudslide quickly buried and preserved organisms

Question 42

how did the evolution of shells contribute to the cambrian explosion

Answer 42

it allowed animals to exploit new environments

Question 43

how did oxygen levels influence the cambrian explosion

Answer 43

increased oxygen in teh air and water supported more complex body plans

Question 44

what role did the ozone later play during the cambrian explosion

Answer 44

helped screen out helpful UV radiation

Question 45

what is meant by an "evolutionary arms race" during the cambrian expliosion

Answer 45

predators/prey rapidly evolved new adaptations in response to each otehr

Question 46

what do most biologists agree about the animal kingdom

Answer 46

that it is monophyletic

Question 47

how many recognized animal phyla are there

Answer 47

about 35

Question 48

what key innovations help classify animals in phylogeny

Answer 48

tissue development, body symmetry, body cavities, embryological development patterns and segmentation

Question 49

what does endoderm form

Answer 49

the lining of the gut

Question 50

what does the ectoderm form

Answer 50

the external covering and the nervous system

Question 51

what does the mesoderm form

Answer 51

muscles of the body wall and most structures between the gut and outer covering

Question 52

what body plan has 2 embryonic layers

Answer 52

diplobastic (endoderm and ectoderm)

Question 53

which type of body plan is found in most animals

Answer 53

triploblastic

Question 54

what is radial symmetry

Answer 54

body parts are arranged around a central axis

Question 55

give examples of animals with radial symmetry

Answer 55

cnidarians (hydras, jellyfish, sea anemones)

Question 56

what is bilateral symmetry

Answer 56

the body can be divided into mirror-large halves along a midline

Question 57

what key features often develops with bilateral symmetry

Answer 57

cephalization (development of a head region)

Question 58

what distinguishes Radiata from Bilateria

Answer 58

radiata have radial symmetry and a mouth at one end; Bilateria have bilateral symmetry, cephalization, dorsal/ventral and anterior/posterior sides

Question 59

what terms are associated with bilaterally symmetrical animals

Answer 59

cephalization, dorsal and ventral, anterior and posterior

Question 60

what does it mean for an animal to be acoelomate

Answer 60

it means the animal has no body cavity

Question 61

give an example of an aceolomate animal

Answer 61

flatworms (phylum platyhelminthes)

Question 62

what does "pseudocoelomate" mean

Answer 62

it refers to animals with a "false" body cavity - not completely surrounded by mesoderm

Question 63

what is a pseudocoelom

Answer 63

a body cavity that is only partially lined with mesoderm

Question 64

give an example of a pseudocoelomate animal

Answer 64

roundworms (phylym Nematoda)

Question 65

what is coelomate

Answer 65

an animal that has fluid-filled body cavity (coelom) completely lined by mesoderm

Question 66

what lines the coelom in vertebrates

Answer 66

the periotneum, which is derived from the mesoderm

Question 67

what surrounds the inner organs in coelomates

Answer 67

mesenteries