Where do animals fit into the tree of life?
Opisthokonts
What are animals most closely related to?
fungi
What are opisthokonts?
the two kinds of multicellular heterotrophs
What are some opisthokonts?
animals, fungi
What are the main differences between animals and fungi in terms of eating?
animals: ingest their food, digest inside bodies;
fungi: secrete enzymes, digest food outside of their bodies
What are most animal diseases?
bacterial
What are most plant diseases?
fungal
What does the term opisthokonts mean and to what cells does it refer?
“flagella coming out of rear” (sperm cells)
What are 11 unique characteristics of animals?
ingest food (hetrorophs); multicellular; sexual reproduction, diploid; most are mobile; aerobic; lack cell walls; glycogen (food storage); develop from a zygote (zygote develops into a gastrula); muscular and nervous tissues; HOX genes control body development
What are the steps of animal development?
- egg meets sperm –> zygote
- cleavage –> 8-cell stage
- cleavage –> blastula
- gastrulation
What is a blastula?
hollow ball of cells
What is gastrulation?
invagination of the hollow ball
Why does gastrulation occur?
sets up embryo to have different germ tissues
What is a blastopore?
opening in cell ball obtained from invagination of blastula
When are germ and somatic cells determined?
single cell stage
When is tissue fate determined?
gastrulation stage
Why do animals start life as a single cell?
so we can produce sexulally;
sexular recombination provides benefits
How many genomes are involved in development?
5 (? - at least 3?)
What genomes are involved in development?
zygote's; maternal; paternal; cytoplasmic factors deposited in the egg by the female; mitochondrial DNA
When does an embryo’s own genes (maternal and paternal combination) start to function?
gastrulation
When do cytoplasmic factors deposited in the egg by the female function in development and how do we know this?
control development to blastula stage;
an egg will develop into a blastula without sperm or nucleus
What are the 3 most characteristic processes of development in animals?
differentiation (into tissues, organs);
growth;
morphogenesis
What is morphogenesis?
development of new shapes, forms
When do the 3 most characteristic processes of development in animals take place?
after cleavage wehn the zygote’s own genes become active;
starts with gastrulation and continues through life of animal
What are the 3 tissue layers of animals?
ectoderm;
endoderm;
mesoderm
How does the mesoderm develop?
trhough induction - interaction between 2 cell types to produce a 3rd
What features are made of the ectoderm?
skin, hair, scales, feathers
What features are made of the endoderm?
gut (digestive system)
What features are made of the mesoderm?
bone, cartilage, blood, most internal organs, gonads (but not actual germ ells)
Where are ectoderm cells located?
on the outside
Where are endoderm cells located?
on the inside
What are some differences in development among animals?
direct vs. indirect development;
determinate vs. indeterminate growth
What is the difference between direct and indirect development?
direct: egg to adult;
indirect: egg to larva to adult
What is the difference between determinate and indeterminate growth?
determinate: grow to adult size
indeterminate: keep growing (though rate may slow)
What are some animals that exhibit determinate growth?
mammals, birds
What are some animals that undergo indeterminate growth?
snakes, lobsters, turtles, fish, frogs, salamanders, lizards, crocodiles
What is the hypothesis for the evolution of animals (steps to becoming an animal?
- aggregation of single cells into a colony
- specialization of functions
- infolding to give digestive cavity and potential for tissue layers
What is a colonial protist?
an aggregate of identical cells
How is body symmetry related to lifestyle?
radial symmetry: primarily sessile/floating;
bilateral: mobile
What lifesyle and body symmetry is often accompanied by cephalization?
mobile;
bilateral symmetry
What is the difference between radial and bilateral symmetry?
radial: any plane cut through the centre gives symmetrical halves;
bilateral: only one plane gives symmetrical halves
What is cephalization?
development of a head
What are two major clades of bilateral animals?
protostomes & deuterostomes
What clade of bilateral animals do humans fit in?
deuterostome
What is the difference between protostomes & deuterostomes?
protostome (“1st mouth”): mouth develops from blastopore;
deuterostome (“other mouth”): anus develops from blastopore
What animals are deuterostomes?
echinoderms (starfish…);
chordates (humans…)
What animals are protostomes?
mollusks (snails…);
annelids (earthworms…);
arthropods (scorpions…)
What 3 groups of bilaterial animals did their common ancestor diverge into?
Lophotrochozoa (protosome),
Ecdysozoa (protostome),
deuterostomia
What did the ancestral colonial choanoflagellate (protist) diverge into and how do they differ?
parazoa (lack true tissues),
eumetazoa (true animals with true tissues)
Into what did the Eumetazoa diverge into?
radiata & bilateria
Why are sponges so simple?
lack true tissues;
some specialization of cells
To what phylum (and subkingdom) do sponges belong?
parazoa (phylum porifera)
What is the characteristic feature of radiata?
digestive cavity tissues
What phylum does the radiata subkingdom comprise?
phylum cnidaria
What are some examples of animals that belong to the phylum cnidaria (radiata)?
jellyfish, corals, sea anenomes
What are the main divisions (phyla) of Lophotrochozoa?
flatworms, annelids, molluscs
What are flatworms?
parasitic forms including the flukes & tapeworms
What are the 3 types of annelids?
earthworms, polychaetes, leeches
What are the characteristics of earthworms and to what phylum do they belong?
terrestrial, ingest soil, extract microorganisms;
annelids
What are the characteristics of polychaetes and to what phylum do they belong?
marine, predators or filter-feeders;
annelids
What are the characteristics of leeches and to what phylum do they belong?
freshwater, bloodsucking;
annelids
What are some examples of molluscs?
scallop, mussel, clam,
smails, nudibrands,
nautlius, squid
What phylum contains the “smart” invertebrates and what are some examples?
mollucs;
squid, cuttlefish, octopuses
What are the most numerous animals in soil?
microscopic free-living nematodes
What parasite is common in vertebrates, and what are some examples?
parasitic nematodes;
hookworm, trichonosis worm, whipworm, pinworm
What are nematodes (other names)?
roundowrms - C. eligans
What phyla are part of the group ecdysozoa?
nematodes, arthropods
What are the unique characteristics of arthropods?
jointed appendages, exoskeleton (that they shed to grow)
What are the 2 types of arthropods (with examples)?
terrestrial arthropods (insects, spiders, centipedes, scorpions); crustaceans (lobsters, crabs, shrimp, amphipods, isopods, barnacles)
What group of arthropods is most marine?
crustaceans
What phyla are part of the group deuterostomia?
echinoderms, chordates
What are the characterstics of echinoderms?
water vascular system, tube feet;
mobile predators, grazers;
larvae are bilaterally symmetric (though develop radial symmetry as secondary adaptation)
What does the water vascular system of echinoderms allow them to do?
move
How do we know echinoderms develop radial symmetry as a secondary adaptation?
larvae are bilaterally symmetric
What are some examples of echinoderms?
sea stars, sea urchins
What are the 3 types of chordates?
cephalochordates, urochordates, vertebrates
To what phylum and subgroup does the Brachiostoma lancet belong?
phylum chordate;
cephalochordates
What 4 features do all chordates share at some point in development?
postanal tail,
notochord,
dorsal hollow nerve cord,
pharyngeal slits
What unique tissue layer do vertebrates have?
neural crest
To what unique structures of vertebrates do the cells of the neural crest give rise?
some of the bones and cartilage of the skull
How does the neural crest develop?
through induction
What is unique about the neural crest cells?
they migrate (most other tissue layers don’t)
What are agnatha?
early jawless fish;
the most primitive living vertebrates
From what are jaws derived?
gill arches
How is the duplication of HOX genes related to animal evolution?
has seemed to allow jaws to develop
What are chondrichthyes?
cartilaginous fish (jawed)
What are osteichthyes?
bony fish (skeletons)
What are the differences between more primitive bony fish (like the gar) and more advanced (like the perch)?
more advanced: pelvic fin closer to head, pectoral fin more on side of body, anal fin more forward (?)
How did fins evolve into limbs?
basal cartilage in fin became humorous, radius, ulna;
digits are novel structures (not from fin rays)
What are fin rays?
long bony extensions
What organism shows evidence of the evolution of limbs from fins?
Coelocanth - living primitive bony fish with lobed fins
What characteristics did the Acanthostega (early tetrapod) have?
ancestrally aquatic,
had lungs and limbs
What are amphibians?
semi-terrestrial tetrapods
What do amphibians rely on?
water, especially for reproduction
In amniote reproduction, where is fertilization?
internal
What is the main difference between the reproduction of mammals and the repdoruction of reptiles & birds?
reptiles & birds lay shelled eggs;
mammals retain amniotic egg in bodies
What is special about an amniotic egg?
has membranes around embryo to protect it
How are amniotes adapted to a fully terrestrial life?
waterproof skin,
efficiently ventilated lungs,
amniotic egg/internal fertilization
How do the adaptations of an amniotic egg and interval fertilization make amniotes more adapted to a fully terrestrial life?
released from breeding in aquatic environment
RECOGNIZE FEATURES THAT DISTINGUISH ANIMALS AND THEIR MAJOR GROUPS
(learning outcome)
EXPLAIN WHY, IN AN EVOLUTIONARY SENSE, ANIMALS START LIFE AS A SINGLE CELL
(learning outcome)
INDICATE WHAT GENOMES ARE IN AN EMBRYO AND WHICH OF THESE CONTROL THE DIFFERENT STAGES OF DEVELOPMENT.
(learning outcome)
IDENTIFY THE DIFFERENT STAGES OF DEVELOPMENT
(learning outcome)
LIST THE 3 TISSUE TYPES IN ALMOST ALL ANIMALS AND INDICATE HOW THEY ARISE
(learning outcome)
BE ABLE TO IDENTIFY THE MAJOR GROUPS OF ANIMALS, OF BILATERAL ANIMALS, AND OF VERTEBRATES
(learning outcome)
BRIEFLY EXPLAIN THE SIGNIFICANCE OF NEURAL CREST AND WHY IT CAN BE CONSIDERED A 4TH GERM LAYER
(learning outcome)
BRIEFLY EXPLAIN HOW LIMBS EVOLVED FROM FINS
(learning outcome)
INDICATE THE CHARACTERISTICS OF AMNIOTES THAT ARE ADAPTED TO TERRESTRIAL LIFE
(learning outcome)
What are the major living groups of reptiles?
(?) crocodilians, squamates, tuatara, turtles
What kind of clade is the clade that contains the major living groups of reptiles?
polyphyletic (?)
To which clade do birds (aves) belong?
amniotes
What are some of the key features of birds adapted to flight?
digits fused and reduced in number (firm aerodynamic surface),
feather barbs have interlocking barbs (y?)
have humerus, radius & ulna…, (?)
very efficient respiration system,
high body temperature (?)
What are the shared derived characters of mammals?
hair,
mammary glands,
muscular diaphragm
What is an example of co-opting an existing structure for a new function?
bones of the middle ear of mammals (?)
What two things differ among the 3 living groups of mammals?
how their young are born,
body temperature
What are the 3 living groups of mammals?
montremes,
marsupials,
placental mammals
How are montremes born and at what temperature do they regulate their bodies?
young hatch from eggs;
regulate body temp at 33 deg
How are marsupials born and at what temperature do they regulate their bodies?
give birth to poorly-developed young that crawl into mother’s pouch and finish developing there;
regulate body temp at 35 deg
How are placental mammals born and at what temperature do they regulate their bodies?
young are nurtured within body of mother by placenta, then born live; (?)
regulate body temp at 37 deg
In what order did the shared derived features (?) appear during the evolution of vertebrates?
notochord, brain, head, vertebral column,
jaws & mineralized skeleton, lungs/lung derivatives,
lobed fins, legs, amniotic egg, milk
From what organism did vertebrates evolve?
ancestral deuterostome
RECOGNIZE ADAPTATIONS TO FLIGHT THAT ARE FOUND IN BIRDS
(learning outcome)
DISTINGUISH THE CHARACTERISTICS OF THE THREE GROUPS OF MAMMALS
(learning outcome)
MATCH THE HOMOLOGOUS BONES OF THE REPTILIAN JAW AND OUR MIDDLE EAR
(learning outcome)
LABEL A CLADOGRAPH OF ANIMAL GROUPS WITH THE DERIVED CHARACTERS THAT DEFINE THE NODES, IN ORDER OF APPEARANCE, IN THEIR EVOLUTIONARY HISTORY
(learning outcome)
