evolution of animals

Question 1

what are animals

Answer 1

• eukaryotes
• multicellular
• heterotroph
• aerobic

Question 2

what are the characteristics of animals

Answer 2

• able to move
• sexual/asexual reproduction
• cells organized into tissues
• development goes through blastula stage
• no cell wall

Question 3

what does multicellularity require

Answer 3

evolution of cell adherence (attachment) and cell signaling (communication)

Question 4

what are cadherins

Answer 4

proteins involved in cell-to-cell attachment

Question 5

what do sponges have

Answer 5

choanocytes: resemble choanoflagellates (feeding by filtration)

amoebocytes: transport nutrients to other cells, can differentiate into any other cell

Question 6

what life cycle do animals go through

Answer 6

diplontic

Question 7

examples of asexual reproduction in animals

Answer 7

• budding in jellyfish
• fragmentation in sponges/flatworms
• parthenogenesis: females produce offspring from unfertilized eggs

Question 8

what are the types of symmetry in animals

Answer 8

• radial symm
• bilateral symm

Question 9

what are hox genes (homeotic genes)

Answer 9

regulatory genes that control placement of body part
–> control developmental fate of groups of cells

Question 10

what are larva

Answer 10

sexually immature phase that is morphologically distinct from adult

Question 11

what is metamorphosis

Answer 11

developmental transformation that turns animal into juvenile that resembles adult
–> not sexually mature yet

Question 12

what is a blastula

Answer 12

when diploid zygote ungerdoes mitosis

Question 13

what is gastrulation

Answer 13

formation of gastrula through infolding
–> forms embryonic tissues that will develop into adult body parts

Question 14

what are the types of cell division

Answer 14

• spiral cleavage : oblique to body axis
• radial cleavage: parallel to body axis
• determinate cleavage: each cell defines specific part of embryo
• indeterminate cleavage: each cell has potential to produce complete embryo

Question 15

what does the blastula develop into

Answer 15

• protosomes: the mouth
• deuterostomes: anus

Question 16

what are the characteristics of protosome development

Answer 16

• spiral cleavage
• determinate
• mouth develops first

Question 17

what are the characteristics of deuterosome development

Answer 17

• radial cleavage
• indeterminate
• anus forms first

Question 18

what embryonic tissues do animals with radial symmetry have

Answer 18

• ectoderm (outer layer)
• endoderm (inner layer)

dipoblastic

Question 19

what embryonic tissues do animals with bilateral symmetry have

Answer 19

• ectoderm
• mesoderm
• endoderm

tripoblastic

Question 20

what is the coelom

Answer 20

cavity lines by tissues derives from mesoderm between digestive track and outer body layer

Question 21

what are the functions of body cavities

Answer 21

• structural support
• transport and diffusion
• allows for growth of organs

Question 22

what are triploblastic animals with no coelom called

Answer 22

acoelomates
–> more efficient digestion

Question 23

what is embryogensis

Answer 23

infolding of neural plate forms neural tube and structures of nervous system

Question 24

what is the notochord

Answer 24

dorsal, longitudinal, flexible rod along anterior-posterior axis of chordates

Question 25

how does surface/volume ratio of animals affect them

Answer 25

surface area smaller for larger organisms, heat loss is decreased

Question 26

what is homeostasis

Answer 26

steady-state physiological condition of body

Question 27

what is thermoregulation

Answer 27

mechanism for regulating body temp

Question 28

endotherm vs. ectotherm

Answer 28

endotherm: source of heat is internal (metabolism) ectotherm: source of heat is external (sunlight)

Question 29

homeotherm vs. poikilotherm

Answer 29

homeotherm (regulator): attenuates variations of internal environ. when external environ. changes poikilotherm (conformed): variations of internal environment can be tolerated when external environ, fluctuates

Question 30

what is osmoregulation

Answer 30

regulation of animal's water loss

Question 31

what are invertebrates

Answer 31

animals with no backbone (spine) ->95% of species

Question 32

what are ecdysozoa

Answer 32

protostome animal that creates exoskeleton periodically molted

Question 33

what can protostome animals possess either of

Answer 33

lophophore: crown of ciliated tentacles around mouth trochophore: larval stage

Question 34

what do chordates possess

Answer 34

- a notochord - dorsal nerve chord - pharyngeal slits behind mouth (filtration) - post-anal tail

Question 35

what is paedomorphosis

Answer 35

retention in adult of juvenile features of its ancestors

Question 36

what are vertebrates

Answer 36

animals with a spinal cord --> muscle attachment

Question 37

what are cyclostomes

Answer 37

vertebrates with NO jaws --> circular mouth - cartilage skeleton, no collagen

Question 38

what are gnathostomes

Answer 38

vertebrates WITH jaws - modification of 2 skeletal rods --> jaws --> support structures - anterior gill slits (suspension feeding, gas exchange)

Question 39

what are chondrichthyes

Answer 39

cartilaginous fish --> have placoid scales

Question 40

what are the 3 modes of reproduction for chondrichthyes

Answer 40

- oviparous: egg laying, external hatching - ovoviviparous: embryo feeds from egg yolk, hatches into uterus - viviparous: embryo feeds from mother through placenta until birth

Question 41

what are osteichthyes

Answer 41

bony fish --> made of calcium phosphate --> have swim bladder --> mostly oviparous

Question 42

what are tetrapods

Answer 42

four limbs with digits --> new land niches

Question 43

what are the adaptations that lead to the colonization of animals to land

Answer 43

- support of body against gravity - breathing air - hearing in air - resistance against dry environments - vascular system with lungs/organs

Question 44

what are the stages for amphibians

Answer 44

1) aquatic larval stage 2) metamorphosis (loss of tail, formation of legs) 3) terrestrial predator adult

Question 45

what are amniotes

Answer 45

clade of tetrapod vertebrates comprising the reptiles, birds, and mammals

Question 46

what are the 4 embryonic membranes for amniotes

Answer 46

- chorion: outer membrane (gas-exchange) - amnion: surrounds cavity - allantois: surrounds disposal sac (metabolic waste) - yolk sac

Question 47

what do reptiles have

Answer 47

- dry skin with scales - ectothermic (except birds) - improved locomotion

Question 48

what are the characteristics of birds

Answer 48

- feathers became an exaptation no bladder light skull for flying

Question 49

what are characteristics of mammals

Answer 49

- produce milk - endothermy - large forebrain - hair/fat layer under skin (insulation) - kidneys

Question 50

what are characteristics of primates

Answer 50

- thumbs - large brain, short jaw - parental care and social behaviours - hand-eye coordination - overlapping visual fields

Question 51

what are characteristics of humans

Answer 51

- bipedal - language - homo neanderthalensis closest relative species