animal diversity + vertebrates Flashcards
what separates animals from plants?
can’t make their own food, no cell wall, cell junctions hold cells in place for communication
suspension feeding
filtering particles from surrounding water
bulkfeeding
eating large food pieces
fluid feeding
sucking fluid out of an animal or sap (think of a spider)
true or false: animals rely on absorptive nutrition
true
what is needed for movement?
muscle and nerve cells organized into tissue
muscle cells are unique to (blank)
animals
why do animals need to move?
find food and run
what systems are needed for movement?
specialized sensory structure + nervous system
sessile species like barnacles have (blank) for moving
appendages or a swimming larval stage
do all animals reproduce sexually
the vast majority of them do
what are the characteristics of the sperm and egg in animals?
the sperm is small and mobile while the egg is large
internal fertilization is common in (blank) species
terrestrial
why is internal fertilization common?
sperm needs a fluid to get to the egg
some animals do reproduce asexually, what are the benefits?
- don’t have to find another mate
- every individual can reproduce
- population increases rapidly
metamorphosis:
developmental phenomena where animal changes from a juvenile to adult
what are the advantages of metamorphasis?
reduces competition and facilitates dispersal (like fruit!)
multicellular animals emerged at the end of what eon?
proterozoic (590 million years ago)
the first animals were what?
invertebrates
what are the explanations of this increase and animal diversity?
- favorable environments, warm temperature, development of ozone layer
- evolution of Hox genes
- An evolutionary “arms race”
why is the development of ozone layer important?
because the sun is strong to scramble DNA and cause cancer without it
what is an evolutionary “arms race”
as organisms evolve, predators make selection pressures which mean the prey evolves (this goes back and forth for millions of years)
what were the first vertebrates?
fish
what was happening while fish were chilling in the ocean?
plants were colonizing the land
what did animals develop for life on land?
lungs, internal fertilization, and amniotic egg
amniotic egg:
develops to keep the embryo safe, a separate membrane holding all the waste
dinosaurs died
65 million years ago
what was the consequence of the dinosaurs going extinct?
explosion of the diversity of mammals
Opisthokonta:
- closest living relatives of animals are choanoflagellates (single-celled protest)
- have a single flagellum surrounded by a collar of tentacle cytoplasm
- choanoflagellates look a lot like sponge choanocytes
what traits are traditionally used to classify animals?
morphological and development features such as
- some kind of body symmetry
- number of germ/developmental layers
- specific features of embryonic development
metazoa
animals
porifera
sponges
porifera have traits such as
- no specialized organs or tissues
- may have distinct cell types
eumetazoa
- more than one type of tissues and organisms, all other animals
eumetazoa is divided by what trait?
symmetry
radial symmetry
can be divided equally by any horizontal plane
radial animals are usually…
circular or tubular in shape, mouth at one end
bilateria are divided by
vertical plane to produce halves
bilateria can have what kind of sides?
dorsal and ventral sides, and also cephalization, anterior and posterior ends
radiata have how many germ layers?
two
cell layers are developed during when?
gastrulation
inner layer:
endoderm
outer layer:
ectoderm
middle:
mesoderm
mesoderm form what?
muscles and other organs
protostomes mean the blastopore turns into the….
mouth
what are other traits of a protostome?
first hole is the mouth AND cleavage determines fate of embryonic cell early
deuterostome means…
the blastopore is an anus
cleavage is indeterminate
each cell produced by early cleavage can develop into a complete embryo
coelom
fluid filled body
pseudocoelomate
coelom only partially lined with mesoderm (rotifers, roundworms)
acoelomate:
lack body cavity, have something else instead
what are the functions of a coelom?
- cushions internal organs
- enables movement and growth of internal organs independent on the body wall
- functions as a hydrostatic skeleton (muscle contractions push fluid from one part of the body to another)
- allows for movement of organisms
- fluid acts as a simple circulation system
coelomate:
completely lined with mesoderm
the body may be divided into regions called (blank)
segments
segmentation occurs in what?
annelids, arthropods, and chordates
what does segmentation allow for?
specialization of body regions
segmented animals have what connecting all the segments?
tissue
hox genes are involved in what?
pattern formation in animal embryos
hox genes come in how many clusters?
4 clusters of 13 genes
simple change in hox expression may account for what?
variation in arthropod appendage types
vertebrates shift in expression in the embryo governs what?
transition from one type of vertebra to another, short/long necks, descent with modification
what do scientists use to classify animals now?
molecular data
closely related organisms have what?
fewer differences in DNA
what are the advantages of morphological data?
genetic sequences are easy to count and compare
studies often focus on what gene?
the gene for small subunit ribosomal dna
hox genes are…
- found in all animals
duplications of hox genes can cause to evolution of
complex body forms
ecdyszoa are what animals?
nematods and arthropods
what are ecydyszoa named for?
molting
member of ecydszoa do what?
secrete an exoskeleton that must be shed and regrown as the animal increases in size
lophotrochozoa are what kind of animals?
mollusks and annelids
what are lophotrochozoa named for?
feeding tentacles and larva
how does one join the lophotrochozoa
get your molecular data analyzed
what are the distinguishing features of chordates?
vertebrae column, cranium, and endoskeleton of cartilage/bone
common features of chordates may include
multiple clusters of hox genes, diversity of internal organisms
what are the side effects of multiple hox genes?
increasingly complex morphologies
notochord
cartilage skeleton rod supporting a body
jawless eel-like animals characteristics
- lack eyes, jaws, and vertebrae
- skeleton compromised of notochord and cartilaginous skull
-blind with a keen sense of smell
cyclostomata characteristics
- have a notochord
- rudimentary vertebral column
gnathostome characteristics
- jawed vertebraes
- jaws allow for efficient prey capture
- hinged jaws developed from gills
- dorsal hollow nerve cord
chondirchthyes characteristics (all of these are misspelled I am so sorry)
- sharks!
- cartilaginous fish
- can find things using electricity
- oxygen is extracted from using gills
- dual chambered hearts
- teeth not set into jaw
- powerful sense of smell
oviparous
lay eggs
ovoviparous
egg retained in female, no placenta
viviparous
eggs develop in uterus, placenta nourishes young
characteristics of cartaliginous fish
- skeleton of flexible cartilage
- derived character with Chondrichthyes
- denser than water
- maintain buoyancy using fins and large oil filled river
osteichthyans characteristics
- include all vertebrae with bony skeleton
- monophyletic origin
actinopterygii:
ray finned fishes
sarcopterygii
lobe finned fishes
operculum
covers gills
what is the swim bladder for?
buoyancy
actinopterygii characteristics
- includes all bony fish but coelocanths and lung fish
- fins supported by thin, bony flexible rays
sarcopterygii characteristics
- includes tetrapods
- fins supported by skeletal extensions of the pectoral and pelvic areas
- moved by muscles
coelocanth characteristics
- believed to be extinct until 1938
- special joint in skull gives powerful bite
- swim bladder filled with oil rather than gas
lungfish
- live in oxygen poor freshwater
- both gills and lungs can drown if unable to breathe air
- muscular lobe allows land travel
what adaptions do tetrapods have for land?
reproducing, movement, and preventing water loss
which group of fish did animals come from?
lobe finned fishes
vertebral column in tetrapods
strengthened, hips and leg bones braced against backbone
what hox genes specify limb formation?
9-13
what are characteristics of the fishapod
broad skull
eyes on top
lungs
pectoral fins with finger-like bones
the fishapod was tied to land for what?
reproduction
when did the fishapod come onto the scene?
320 million years ago
mutations in hox genes result in..
loss of radula, ulna, and carpals
a simple hox gene mutation can lead to
large changes in limbs
amphibians successfully colonized land, what is the one thing they are tied to water for?
fucking
how do amphibians breathe?
with lungs and skin
how do amphibians lungs work
bucca pumping forces air in
amphibians fertilize their eggs
externally
do amphibians go through metamorphasis?
yes, their larval stage is aquatic
tetrapods developed what that was critical?
development of shelled egg
the amniotic egg did what?
removed the tie from water
most mammals have an embryo…
embedded in the uterine wall
what are other key innovations of mammals
- resisting water loss
- keratin
thoraic breathing
what is thoraic breathing?
negative pressure sucks in air
feathers are modified what
scales
mammals evolved from amniote ancestors
earlier than birds
characteristics of mammals
- mammary glands for milk
external food provisioning
have hair
only vertebraes with special teeth
enlarged skull
additional features of animals
digest plants using bacteria
primates are
tree dwelling species
primates evolved
85 million years ago
primates have
opposable thumbs, large digits with flat nails, complex social behavior, well-developed parental care, binocular vision
