zoo quiz (4/29)

Chordates: protostomes or deuterostomes?

deuterostomes

3 ancestral characteristics of chordates

1. bilateral symmetry

2. cephalization

3. metamerism

2 closest sister groups to chordata

1. echinoderms

2. hemichordates

Notochord structure + function

flexible rod for support and muscle attachment

dorsal nerve cord origin + other details

ectodermal; brain+spinal cord in vertebrates

pharyngeal slits origin + function

ectodermal and endoderm; early: filter feed. fish: gills, tetrapods: pouches

endostyle

mucus and iodine hormones (filter feeding)

thyroid

thyroxine production

2 functions of post-anal tail

1. propulsion

2. balance

urochordata adults have what 2 traits

endostyle and slits

urochordata sessile or mobile

sessile

what are urochordata made of

cellulose

cephalochordata scavengers or filter feeding

filter feeding

structures of cephalochordata

buccal cavity, pharynx, gill slits, endostyle, atriopore

type of circulation in cephalochordate

closed

key vertebrate adaptations

endoskeleton, increased size, exoskeleton (sometimes), mineral storage

segmented muscles in vertebrates

myomeres

vertebrate head features

forebrain, midbrain, hindbrain, cranium

neural crest

skull and structures

placodes

sensory organs

when did vertebrates appear

early cambrian

key traits of gnathostomes

1. jaws

2. paired fins/limbs

evolution of jaws

modified gill arches

skeleton of Chondrichthyes (

cartilage

3 types of reproduction

1. oviparous

2. ovoviviparous

3. viviparous

swim bladder function

buoyancy

operculum function

protect gills, pump water, streamlining

freshwater fish osmoregulation challenge

gain water, lose salt

saltwater fish osmoregulation challenge

lose water, gain salt

ancestors of tetrapods

sarcopterygii

why did amphibians move to land

more resources, new habitats, drying water

challenges of land

gravity/support, temp changes, desiccation, o2 differences

choanae function

internal nostrils for breathing

amphibian circulation

double

amphibian life cycle

aquatic eggs/larvae, terrestrail adults, metamorphosis

respiration type in amphibians

cutaneous

paedomorphosis

adult retains juvenile traits

amphibians are what type of thermoregulators

ectothermic

order gymnophiona

caecilians

order anura

frogs

order caudata

salamanders

why are amphibians declining

habitat loss, sensitive skin, chytrid fungus

heart mammals have

4 chambered

double circulation meaning

blood flows through heart twice per circuit (pulmonary + systemic)

endothermy

internal metabolism that maintains body temp

cost of endothermy

must constantly eat to maintain metabolism

higher metabolism in

small animals

slower metabolism in

large animals

diaphragm

muscle that increases thoracic cavity volume for breathing

why is the diaphragm important

improves ventilation efficiency compared to other amniotes

exocrine glands

secretes through ducts (sweat, mammary)

endocrine glands

release hormones into bloodstream (thyroid)

origin of exocrine glands in mammals

epidermally derived

2 types of sweat glands

1. eccrine

2. apocrine

eccrine gland function

watery sweat, thermoregulation, nervous sweating

apocrine gland function

associated with hair follicles, oily secretions, distribute pheromones

scent glands are used for

reproductive signaling, defense, and territorial marking

what do sebaceous glands produce

sebum (oily/waxy substance)

function of sebum

waterproofing and keeps hair pliable and glossy

where are sebaceous glands found

associated with hair follicles

when do mammary glands lactate

during/after pregnancy (stimulated by prolactin)

what do mammary glands produce

milk

let down reflex

positive feedback loop

suckling

oxytocin release

oxytocin causes

milk release

adaptive benefit of milk

allows feeding of young even when external food is scarce

cost of milk production

high energy

do both sexes have nipples/teats?

yes

origin of hair

epidermal

3 layers of hair

1. medulla

2. cortex (pigment, flexibility)

3. cuticle

what is hair made of

keratin

3 functions of hair

1. insulation

2. sensory (whiskers)

3. protection

other keratinized structures in mammals

nails/claws

horns

baleen

antlers

single jaw bone condition

lower jaw is one dentary bone= stronger bite

what happened to other ancestral jaw bones

became middle ear bones

what is diphyodont dentition

two sets of teeth (baby and adult)

heterodont dentition

4 types of teeth

4 types of teeth and functions

1. incisors (cutting

2. .canines (capturing/defense)

3. premolars (grinding/slicing)

4. molars (grinding/slicing)

bony secondary palate

seperates nasal and oral cavities (allows for breathing while nursing)

why is the secondary palate important

suckling while breathing

frugivore teeth

adapted for soft fruit

insectivore teeth

sharp, pointed teeth for exoskeletons