animal diversity Flashcards
1
Q
Diplontic life cycle
A
refers to the life cycle of organisms, which is dominated by the diploid stage
2
Q
Asymmetry
A
lack symmetry altogether
EX: sponges
3
Q
Radial symmetry
A
symmetry in which the body is shaped like a pie or barrel (lacking a left side and a right side) and can be divided into mirror-imaged halves by any plane through its central axis
ex: flower pot or sea anemone
4
Q
Oral-aboral axis
A
radially symmetrical cnidarians have multiple planes of symmetry
- with this they only have a single body axis - the oral-aboral axis
- these organisms have their mouth on the ORAL surface & their opposite side is the ABORAL side
5
Q
Bilateral symmetry
A
a central longitudinal plane divides the body into 2 equal but opposite halves
ex: shovel or lobster
6
Q
Cephalization
A
an evolutionary trend toward the concentration of sensory equipment at the anterior (head) end of the body
7
Q
Anterior-Posterior axis
A
anterior: front
posterior: rear
8
Q
Dorsal-Ventral axis
A
dorsal: top
ventral: bottom
9
Q
True Tissue
A
in animals, true tissues are collections of specialized cells isolated from other tissues by membranous layers
- sponges and a few other groups lack true tissues
10
Q
Diploblastic
A
having 2 germ layers
11
Q
Triploblastic
A
possessing 3 germ layers: the endoderm, mesoderm, and ectoderm
- most eumetazoans are triploblastic
12
Q
Endoderm
A
the innermost germ layer, lines the pouch that forms during gastrulation (the archenteron) and gives rise to the lining of the digestive tract (or cavity) and organs such as the liver and lungs of vertebrates
13
Q
Mesoderm
A
which fills much of the space between the ectoderm and endoderm
- in a triploblastic, bilaterally symmetrical, animals
14
Q
Ectoderm
A
the outermost germ layer covering the surface of the embryo, gives rise to the outer covering of the animal and, in some phyla, to the central nervous system
15
Q
Coelom
A
a body cavity lined by tissue derived only from mesoderm
- it’s a space that opens up within the mesoderm (which means all coelomates are triploblasts) that cushions and protects the organs, provides the stiffness in hydrostatic skeletal systems, and has been lost in some lineages (which means not all triploblasts are coelomates).
16
Q
Acoelomate
A
a solid-bodied animal lacking a body cavity between the gut and outer body wall
17
Q
Pseudocoelomate
A
animals with only a hemocoel
18
Q
(Eu)coelomate
A
an animal that has a true coelom (fluid filled body cavity) which surrounds the gut and is lined on both sides by mesoderm
19
Q
Segmentation
A
segments are when a body plan has repeated body sections
- in Annelids, Arthropods and Chordates
20
Q
Protostome
A
in animals, a developmental mode distinguished by the development of the mouth from the blastopore; often also characterized by spiral cleavage and by the body cavity forming when solid masses of mesoderm split
EX: molluscs, annelids
21
Q
Spiral cleavage
A
a type of embryonic development in protosomes in which the planes of cell division that transform the zygote into a ball of cells are diagonal ot the vertical axis of the embryo. As a result, the cells of each tier sit in the grooves between cells of adjacent tiers
22
Q
Determinate development
A
of some animals with protostome development rigidly casts (“determines”) the developmental fate of each embryonic cell very early
- a cell isolated from a snail at the four-cell stage, for example, cannot develop into a whole animal
- instead, after repeated divisions, such a cell will form an inviable embryo that lacks many parts
23
Q
Schizocoely
A
in protostomes, part of the mesoderm separates to form the coelom in a process called schizocoely
24
Q
Deuterostome
A
in animals, a developmental mode distinguished by the development of the anus from the blastopore; often also characterized by radial cleavage and by the body cavity forming as out-pockets of mesodermal tissue
EX: echinoderms, chordates
25
Radial cleavage
a type of embryonic development in deuterostomes in which the planes of cell division that transform the zygote into a ball of cells are either parallel or perpendicular to the vertical axis of the embryo, thereby aligning tiers of cells one above the other
26
Indeterminate development
meaning that each cell produced by early cleavage divisions retains the capacity to develop into a complete embryo
ex: if the cells of a sea urchin embryo are separated at the four-cell stage, each can form a complete larva
- similarly, this in the human zygote that makes identical twins possible
27
Enterocoely
in deuterostome animal embryo develop, the mesoderm pinches off of the digestive tract to form the coelom in a process called enterocoely.
28
Invertebrates
an animal without a backbone (makes up 95% of animal species)
29
Vertebrates
a chordate animal with a backbone, including sharks and rays, ray-finned fishes, coelacanths, lungfishes, amphibians, reptiles, and mammals
30
Mesohyl
a gelatinous region between the 2 layers of cells in a sponge ("middle matter")
- b/c both cell layers are in contact with water, processes such as GAS EXCHANGE and WASTE REMOVAL can occur BY DIFFUSION across the membranes of these cells
31
Choanoderm
a type of cell layer composed of flagallted collar cells, or choanocytes, found in sponges
32
Pincaocytes
one of the flat cells covering the external surface and lining the incurrent and excurrent canals of sponges are part of the epithelium in sponges
- they play a roll in MOVEMENT (contracting and stretching, cell adhesion, signalling, phagocytosis, and polarity
- are filled with mesophyl
33
Choanocytes
a flagellated feeding cell found in sponges
| - also called collar cell, it has a collar-like ring that traps food particles around the base of its flagellum
34
Amoebocytes
an amoeba-like cell that moves by pseudopodia and is found in most animals
- depending on the species, it may digest and distribute food, dispose of wastes, form skeletal fibres (spicules), fight infections, or change into other cell types
35
Spicules
tough sharp skeletal fibres made of calcium carbonate or silica; which can be produced by amoebocyte cells
- found in porifera/sponges
36
Totipotent
they can differentiate into other types of sponge cells, like stem cells
- this gives the sponge body remarkable flexibility, enabling it to adjust its shape in response to changes in its physical environment (such as the direction of water currents)
- basically can transform into any cell type that is needed by the body
37
Pluripotent
describing a cell that can give rise to many, but not all, parts of an organism
38
Multipotent
have the ability to form multiple types of cells
39
Gastrovascular cavity
a central cavity with a single opening in the body of certain animals, including cnidarians and flatworms, that functions in both the digestion and distribution of nutrients
40
Complete gut
digestive tract, which is a group of tissues or organs designed to break down food
41
Epidermis
the OUTMOST layer of cells in an animal of CNIDARIANS; derived from ECTODERM
- have bundles of mircofilaments arranged into contractile fibres
42
Mesoglea
gelatinous layer between the epidermis and gastrodermis
43
Gastrodermis
the INNERMOST layer of cells in an animal of CNIDARIANS
| - have bundles of microfilaments arranged into contractile fibres
44
Polyp
the sessile variant of the cnidarian body plan
- are cylindrical forms that adhere to the substrate by the aboral end of their body (the end opposite the mouth) and extend their tentacles, waiting for prey
EX: hydras and sea anemones
45
Medusa
the floating, flattened, mouth-down version of the cnidarian body plan
- it moves freely in the water by a combination of passive drifting and contractions of its bell-shaped body
EX: free-swimming jellies
46
Cnidocyte
a specialized cell unique to the phylum Cnidaria; contains a capsule-like organelle housing a coiled thread that, when discharged, explodes outward and functions in prey capture or defence
47
Super organism
is a group of synergetical interacting organisms of the same species
48
Gastrozooid
2 types of polyps:
| the first is gastrozooid, which is adapted for capturing prey and feeding
49
Dactrozooid
a tentacular mouthless zooid in certain hydrozoans that performs tactile and protective functions for the colony.
50
Autozooid
a zooid that is able to feed.
51
Gonozooid
are any of the reproductive individuals of Tunicates, Bryozoan, or Hydrozoan colonies that produce gametes.
52
Blastropore
in a gastrula, the opening of the archenteron that typically develops into the anus in deuterostomes and the mouth in protostomes
53
Pentaradial symmetry
for the ECHINODERMS:
- larvae = bilateral symmetry
- adults = pentaradial symmetry (acquired during metamorphosis)
- in pentaradial symmetry, there are exactly 5 planes of symmetry
exception: sea cucumbers
54
Water vascular system
the COELOM of the ECHINODERMS has been modified into this which is unique to echinoderms that branches into extensions called TUBE FEET, which function in LOCOMOTION & FEEDING
- also used for SENSATION and/or GAS EXCHANGE
55
Notochord
a longitudinal, flexible rod made of tightly packed mesoderm cells that runs along the anterior posterior axis of chordate in the dorsal part of the body, for muscle attachment and support
- in humans, only in early development and releases growth factors and goes away (not used for structure)
56
Pharyngeal gill arches/slits
in chordates embryos, one of the slits that form from pharyngeal clefts and communicate to the outside later developing into gill slits in many vertebrates:
- filter-feeding organs
- water goes through and the gills just grab whatever food is available in the water
- in humans it goes away after
57
Post-anal tail
in chordates:
- it is a muscular tail that extends posterior to the anus, contains skeletal elements and muscles helps propel many aquatic species
- have a tail that extends posterior to the anus, although in many species it is greatly reduced during embryonic development
- in humans it goes away
58
Dorsal, hollow nerve cord
in chordates:
- develops from a plate of ectoderm that rolls into a tube located dorsal to the notochord
- unique to chordates
- connects brain with basically all other tissue
- the nerve cord of a chordate embryo develops into the central nervous system: the brain and spinal cord
59
Jaws (jawed vertebrates)
gnathostomes ("jaw mouth") are named for their jaws, hinged structures that, especially with the help of teeth, enable gnathostomes to grip food items firmly and slice them
- clade of the phylum chordata
- 3 groups:
1. Rays & Sharks ("cartilaginous")
2. Ray-finned fishes ("boney" ex: trout, salmon, goldfish etc. any fish really
3. Lobe-finned fishes
a. coelacanth - deep sea animals
b. lungfishes - have lungs & breath like we do
3rd is tetrapods (not really fish)
- amphibians, reptiles (including birds), and mammals
60
Cartilaginous (Fish)
- is a class of the phylum chordata
- Sharks, Rays, and Ratfishes
- skeletal rods (cartilaginous "bones") modified into jaws
- vertebrae filled out to make a complete skeleton:
- still only cartilaginous (softer & flexible)
- provides still structure for bigger muscles and improved swimming
- provides protection to nervous system
- electrical sensation
- lateral line
61
Boney (Fish)
- a class of the phylum chordata
- ray-finned fish
EX: trout, salmon, goldfish, salamanders, etc. (any fish)
- true bones (calcium phosphate-based)
- better protection to nervous system
- can accomodate even bigger, more powerful muscles
- improves swimming even more
- SWIM BLADDER
- a "lung derivative" (air pocket)
- improves buoyancy, & thus swimming ability
- OPERCULUM
- protects gills
- allows breathing without swimming
62
Limbs
an arm or leg of a person or four-legged animal, or a bird's wing.
63
Amnion
encloses a compartment of fluid that bathes the embryo and acts as a hydraulic shock absorber
64
Mammary gland
an exocrine gland that secretes milk to nourish the young
| - mammary glands are characteristics of mammals
65
Continuous growth
lophotrochozoa grow continuously
- juveniles (the life cycle stage after larvae that look similar to adults) gradually get larger until they reach their adult size
66
Lophophore
in some lophotrochozoan animals, including brachiopods, a crown of ciliated tentacles that surround the mouth and function in feeding
67
Trochophore
distinctive larval stage observed in some lophotrochozoan animals, including some annelids and molluscs
68
Free-living
free-living rhabditophorans are important as predators and scavengers in a wide range of freshwater and marine habitats
- the best-known members of this group are freshwater species in the genus Dugesia, commonly called planarians
69
Parasitic
more than half of the known species of rhabditophorans live as parasites in or on other animals
- many have suckers that attach to the internal organs or outer surfaces of the host animal
- in most species, a tough covering helps protect the parasites within the host
- reproductive organs occupy nearly the entire interior of these worms
- 2 important subgroups of parasitic rhabditophorans
- trematodes
- tapeworms
70
Muscular foot
1 of the 3 main parts of a mollusc; a muscular structure usually used for movement/locomotion
71
Visceral mass
1 of the 3 main parts of a mullusc; the part containing most of the internal organs
72
Mantle
1 of the 3 main parts of MOST mollusc; a fold of tissue that drapes over the mullusc's visceral mass and may secrete a shell (exoskeleton)
- it is NOT shed (they just add on as necessary)
73
Mantle cavity
a water-filled chamber that houses the gills, anus, and excretory pores of a mollusc
74
Radula
a straplike organ used by many molluscs during feeding to scrape food
75
Chromatophores
?? are pigment-containing cells, or groups of cells, found in a wide range of animals including amphibians, fish, reptiles, crustaceans and cephalopods. ??
76
Parapodia
(beside feet) a pair of prominent paddle like or ridge like structures
77
Palps
a pair of appendages, that function in sensing, feeding, or reproduction
- food particles suspended in water enter through the incurrent siphon are collected by the gills and passed to the mouth by palps and cilia
78
Cuticle
the exoskeleton of an arthropod, consisting of layers of protein and chitin that are variously modified for different functions
- a tough coat that covers the body of a nematode
- must be shed as animal grows (a process called "ecdysis") AKA molting exoskeleton
79
Exoskeleton
a hard encasement of the surface area of an animal, such as the shell of a mollusc or the cuticle of an arthropod, that provides protection and points of attachment for muscles
80
Step-wise growth
ecdysozoa (ex: nematodes & arthropods) grow by spurts in a stepwise pattern
- they are covered by a cuticle (hardened covering), which prevents continual growth
- in order to grow, these animals must periodically shed this cuticle (molt) & grow rapidly before creating a new one
81
Moulting
a process in ecdysozoans in which the exoskeleton is shed at intervals, allowing growth by the production of a larger exoskeleton
82
Uniramous
It consists of an unbranched series of segments (for anthropod leg).
83
Biramous
dividing to form two branches (for anthropod leg).
84
Chelicera
1 of a pair of clawlike feeding appendages, characteristics of chelicerates
85
Tagma
arthropod segments have also fused together into functional units called tagma. This process of segment fusion, or tagmosis, usually results in an arthropod body that consists of three major sections, a head, thorax, and abdomen
86
Head
of the arthropods, specifically Chelicerates
87
Thorax
of the arthropods, specifically Chelicerates
88
Cephalothorax
head + thorax
89
Abdomen
a lot of gut, typically no appendages off the abdomen
90
Complete metamorphosis
the transformation of a larva into an adult that looks very different, and often functions very differently in its environment, than the larva
91
Incomplete metamorphosis
a type of development in certain insects, such as grasshoppers, in which the young (called nymphs) resemble adults but are smaller and have different body proportions.
- the nymph goes through a series of moults, each time looking more like an adult, until it reaches full size
92
Explain the evidence of shared ancestry between the animals and choanoflagellates.
1. Morphologically, choanoflagellate cells and the collar cells (or choanocytes) of sponges are almost indistinguishable.
2. Similar collar cells have been identified in other animals, including cnidarians, flatworms, and echinoderms-but they have never been observed in non-choanoflagellate protists or in plants or fungi.
3. DNA sequence data indicate that choanoflagellates and animals are sister groups. In addition, genes for signalling and adhesion proteins previously known only from animals have been discovered in choanoflagellates.
page 715 fig 32.3
93
Describe the defining characteristics of animals.
1. Eukaryotic
2. Multicellular
3. Chemoheterotrophic -> an organism that requires organic molecules for both energy and carbon
4. All individuals are diploid; only gametes are haploid
5. No cell walls; use extracellular structural proteins instead
- in particular collagen, the most abundant protein in your body (1/3 of all your protein)
6. Ingest food
94
Illustrate the typical animal life cycle in regards to GASTRULATION.
1. The zygote of an animal undergoes a series of mitotic cell divisions called CLEAVAGE
2. An eight-cell embryo is formed by 3 rounds of cell division
3. In most animals, cleavage produces a multicellular stage called a BLASTULA. The blastula is typically a hollow ball of cells that surround a cavity called the BLASTOCOEL.
4. Most animals also undergo GASTRULATION, a process in which one end of the embryo folds inward, expands, and eventually fills the blastocoel, producing layers of embryonic tissues: the ECTODERM (outer layer) and the ENDODERM (inner layer)
5. The pouch formed by gastrulation, called the ARCHENTERON, opens to the outside via the BLASTROPORE
95
Compare and identify examples of asymmetry, radial symmetry, and bilateral symmetry.
ASYMMETRY -> sponge (lack symmetry altogether)
RADIAL SYMMETRY -> flower pot or sea anemone
- a radial animal, such as a sea anemone (phylum Cnidaria), does not have a left side and a right side
- any imaginary slice through the central axis divides the animal into mirror images
BILATERAL SYMMETRY -> shovel or lobster
- 2 sided symmetry
- a bilateral animal, such as a lobster (phylum Arthopoda), has a left side and a right side
- only 1 imaginary cut divides the animal into mirror-image halves
- such animals have DORSAL (top) side and a VENTRAL (bottom) side, a left side and a right side, and an ANTERIOR (front) end and a POSTERIOR (back) end
96
a. Explain which character is ancestral or derived.
asymmetry is ancestral and radial & bilateral symmetry is derived.
97
b. Describe the advantage of cephalization.
Many animals with a bilaterally symmetrical body plan (such as arthropods and mammals) have sensory equipment concentrated at their anterior end, including a central nervous system ("brain") in the head-an evolutionary trend called CEPHALIZATION (Greek word, head)
- is the development of a control center or brain.
98
Describe what a true tissue is and identify taxa that have them.
in animals, TRUE TISSUES are collections of specialized cells isolated from other tissues by membranous layers
- sponges and a few other groups lack true tissues
Taxa with true tissue:
1. Cnidarians
2. Flatworms
3. Molluscs
4. Annelids
5. Nematods
6. Arthropods
7. Echinoderms
8. Chordates
99
Compare diploblastic and triploblastic embryos and identify example of each.
1. Cnidarians and a few other animal groups that have only these 2 germ layes (endo and ecto) are said to be DIPLOBLASTIC
EX: Cnidarians
2. All bilaterally symmetrical animals have a 3rd germ layer, called the MESODERM
- also said to be TRIPLOBLASTIC
EX: include a broad range of animals, from flatworms to arthropods to vertebrates
100
Describe the different body cavity types and identify examples of each.
all triploblasts (bilateria)
1. COELOM/COELOMATE
- have a true COELOM, a body cavity completely lined by tissue derived from mesoderm
EX: earthworms
2. PSEUDOCOELOMATE/HEMOCOEL
- have a body cavity lined by tissue derived from mesoderm and by tissue derived from endoderm
EX: roundworms
3. ACOELOMATE/COMPACT
- lack a body cavity between the digestive cavity and outer body wall
EX: planarians
101
Compare the general features of protosomes and deuterostomes and identify examples of each.
a. Cleavage pattern
b. Mechanism of coelom formation
c. Fate of the blastopore
all triploblasts (bilateria)
protosome: mouth forms 1st
deuterosome: anus forms 1st
a. Cleavage pattern:
protosomes: begins with spiral, determinate cleavage
deuterosomes: characterized by radial, indeterminate cleavage
b. Coelom formation: (begins in gastrula stage)
protosomes: the coelom forms from splits in the mesoderm
deuterosomes: the coelom forms from mesodermal outpocketings of the archenteron
c. Fate of the blastopore:
protosomes: the mouth forms from the blastopore
deuterosomes: the mouth forms from a secondary opening
EX of PROTOSOMES: molluscs, annelids
EX of DEUTEROSTOMES: echinoderms, chordates
102
Summarise the major events that occurred during the evolution of the animals.
- true tissue
- body symmetry
- blastopore fate
- growth pattern
103
Describe the basic body plans for the PORIFERA phylum
asymmetric body plan
- no nervous system, but individual cells contain much of the machinery of typical animal nerve cells
- adults are sessile (larvae swim)
104
Describe the basic body plans for the CNIDARIA phylum
a sac with a central digestive compartment, the GASTROVASCULAR CAVITY
- a single opening to this cavity functions as both mouth and anus
- 2 variations to this body plan: the sessile POLYP and the motile MEDUSA
- extremely SIMPLE nervous system (no brain, just randomly distributed neural network)
105
Describe the basic body plans for the ECHINODERMATA phylum
deuterostome bilateria (anus 1st)
- LARVAE are BILATERALLY symmetrical; ADULTS are RADIALLY symmetrical
- posses ENDOSKELETON, extensions of which from the exterior spines
- most locomote using TUBE FEET & WATER VASCULAR SYSTEM
106
Describe the basic body plans for the CHORDATA phylum
bilaterally symmetrical
- dorsal, hollow nerve cord
- notochord
- pharyngeal slits
- muscular post-anal tail
107
Describe the basic body plans for the PLATYHELMINTHES phylum
aka flatworms
- although they undergo triploblastic development, they are acoelomates (animals that lack a body cavity)
- bilateral symmetry
- 1 digestive system opening (0 in flatworms)
108
Describe the basic body plans for the BRACHIOPODA phylum
within the lophotrochozoa
- follows the deutersome pattern!
- have ciliated feeding structure
- cilia create water currents & filter out suspended food particles
- sessile; attach firmly to their substrate
- all are dioecious & reproduce sexually
- larvae are ciliated & swim before they go through metamorphosis
109
Describe the basic body plan for the MOLLUSCA phylum
bilaterial, triploblastic, protosome
- foot, visceral mass, mantle
- complete, one-directional digestive tract with specialized regions (2 digestive openings)
- complex internal organs/systems
- OPEN circulatory system
- COMPLETE nervous system
- SENSORY ORGANS like eyes, they also have brains
110
Describe the basic body plan for the ANNELIDS (segmented worms) phylum
bilateral, triploblastic, protosome
| - SEGMENTED body plan (defining characteristic!)
111
Describe the basic body plan for the NEMATODES (roundworms) phylum
bilateral triploblastic, protosome
- exdysozoa: CUTICLE (exoskeleton) must be shed as animal grows (a process called "ecdysis") AKA molting exoskeleton
- problem:
- exoskeleton completely encases the animal (can't add onto shell b/c no room)
- mollusc - type growth impossible
- exoskeleton is abiotic (doesn't grow, rigid & not alive)
- can't just grow like living skin (line annelid worms, for instance)
- COMPLETE digestive tract
112
Describe the basic body plan for the ARTHROPODS phylum
- SEGMENTED body plan
- segments FUSE to form major body parts! ex: distinct head, thorax, and abdomen
- JOINTED appendages (legs and antennae)
- OPEN circulatory system (DON'T have blood vessels)
113
Know the difference between the coelom fluid and hemolymph
Coelomic fluid:
- is the fluid within the coelom or body cavity. It functions as a hydrostatic skeleton. It also serves as a circulatory medium. It helps in locomotion. Mesodermal tissue is the source of coelomic fluid.
Hemolymph:
in invertebrates with an open circulatory system, the body fluid that bathes tissue
- like many molluscs, arthropods have an open circulatory system, in which fluid called hemolymph is propelled by a heart through short arteries and then into spaces called sinuses surrounding the tissues and organs
114
Know the difference between the coelom and the hemocoel
Coelom:
a body cavity lined by tissue derived only from mesoderm
- it's a space that opens up within the mesoderm (which means all coelomates are triploblasts) that cushions and protects the organs, provides the stiffness in hydrostatic skeletal systems, and has been lost in some lineages (which means not all triploblasts are coelomates).
Hemocoel:
- in many triploblastic animals a 2nd body cavity type can form between endoderm and mesoderm that is likely a remanent of the blastocoel
115
What is it mean for PORIFERA/sponges to be hermaphroditic?
meaning that each individual functions as both male and female in sexual reproduction by producing sperm AND eggs
116
What is it mean for PORIFERA/sponges to be sequentially hermaphroditic AND what is the benefit?
they function 1st as one sex and then as the other
BENEFIT: limits possibility of selfing (mating with itself), so if it is forced to mate with other individuals instead of itself it ENHANCES GENETIC DIVERSITY
117
Are cnidarians protosomes or deuterostomes?
neither! because 1 opening and it is BOTH mouth and anus 1st
118
Which phylum is known for by far the biggest super phylum within the bilateria?
lophotrochozoa (includes molluscs) within the bilateria
119
What is the BENEFIT of having a complete digestive tract with 2 openings?
- in flatworms and cnidarians, they have a single opening, so they have to eat their food, digest and ingest it and then open their mouth again and expell whatever they couldn't digest so, ONLY 1 EVENT COULD OCCUR AT A TIME
- BUT, if you have a complete digestive tract (2 openings), these events can occur SIMULTANEOUSLY because they have specialized regions along the digestive tract
- so as they are eating, the crop is crunching ip previous eaten food, later digestive system is digesting and then later ejecting left over food that couldn't be digested so it is more EFFICIENT
120
How are different segments made differently?
"Hox gene magic!"
- all animals have a set of hox genes (wide variety of genes that are very specialized and they overlap each other in their expression timing) and they determine when things grow and where (just because they know which segment their in, they know whether they switch on or not)
- basically, hox genes determine where the brain, sex organs, intestine etc. is/are going to go (they control how the changes occur from one segment to the next) they can be manipulated too to be tricked into growing things in random places
121
How do worms move?
longitudinal & circular muscles plus a hydrostatic skeleton allows for control of shape, direction, and motion
- b/c some segments elongate while other segments constrict by alternating the circular & longitudinal muscle
EX: like balloon animal
122
Which phylum is known for far more species?
Ecdysozoa within the bilateria
| - largely b/c Arthropodia are extremely numerous and diverse (especially insects)
123
How do the Nematodes perform the molting of their exoskeleton (which has to be done on occasion as the animal grows)?
when the animal outgrows its cuticle (exoskeleton), it grows a new cuticle underneath the old one
- then it breaks out of the old one, but while the new cuticle is not hardened yet, the body then stretches out (blows itself out, as big as it can and holds itself that way) until new cuticle hardens then the body can relax itself and there is now extra space to grow and then repeats later!
124
What are Arthropods best known for?
most species in this phylum than any other species on earth combined!
125
How many pairs of wings do ALL insects have?
either 0 or 2 pairs of wings! (some have been modified)
126
What does Metazoan mean?
means animal or (later/after animal)
| - used to be thought that animals were unicellular - protozoans
127
What does autotrophic and chemoheterotrophic mean?
autotropic: capable of making their own food - though photosynthesis
chemoheterotrophic: get their fuel/energy from other organisms
128
Blastula
takes the form of a hollow ball of cells that marks end of cleavage stage
129
Gastrulation
series of cell and tissue movements in which the blastula - stage embryo folds inward producing a 3 layer embryo the gastrula
130
Gastrua
encompasses the formation of 3 layers: ectoderm, mesoderm and endoderm
131
Larvae
sexually immature form of a an animal that is morphogically distinct from the adult usually eats different food and may even have a different habitat than the adult
132
Blastocoel
the fluid-filled cavity that forms in the centre of a blastula
133
Blastopore
in a gastrula the opening of the archenteron that typically develops into the anus in deuterostomes and mouth in protostomes, the indentation that during gastrulation leads to the formation of the archenteron
134
Archenteron
the endoderm lined cavity formed during gastrulation that develops into the digestive tract of an animal
135
For the Echinoderms, what type of symmetry does the larvae have compared to the adults?
well, their larvae are bilaterally symmetrical; adults are radially symmetrical
- this radial symmetry is novel, not evolved from cnidarian radial symmetry
136
What are the 4 defining characteristics of invertebrates (chordates)?
- dorsal, hollow nerve chord
- notochord
- pharyngeal slits
- post-anal tail
137
What do invertebrates & vertebrate chordates have in common?
- dorsal, hollow nerve chord
- notochord
- pharyngeal slits
- post-anal tail
138
What are the defining characteristics of vertebrates?
- dorsal, hollow nerve chord
- notochord
- pharyngeal slits
- post-anal tail
- multiple sets of HOX GENES
- NEURAL CREST CELLS
139
Compare and contrast the previous hypothesis with the current hypothesis for the evolution of Lungfish to Amphibians?
previous:
- lunged fish dragged themselves from pond to pond
- legs eventually evolved
current:
- lunged fish evolved 4 legs and a neck
- THEN they were able to drag themselves from pond to pond
140
Which vertebrates were the 1st to leave the water?
tetrapods (amphibians)
| - vertebrates with 4 true legs
141
For the tetrapods (amphibians) how do they breathe?
no more gills (in most adults); most larvae still need gills (cause they live in the water)
- some breathe through the skin & some have even lost their lungs
142
Why do the amniotes have full adaptation to life on land?
b/c they have waterproof skin
| - & b/c named for the amniotic egg
143
What are the 5 main components of the amniotic egg?
1. amnion - fluid-filled sac containing the embryo
2. yolk sac - food source for embryo
3. allantois - handles waste & gas exchange
4. chorion - helps with gas exchange
5. water-proof shell - in most amniotes
144
What is the perk of the water-proof shell in most amniotes on the amniotic egg?
- can allow air to go in & out but is impermeable (doesn't allow water to pass through)
- which is what prevents the amniotic egg from drying out & why it could be laid in dry air on the ground (doesn't have to be in water)
145
Reptiles are...
ECTOtherms (non-avian)
- low energy demands
- obtain their heat from outside their bodies
146
What is the BENEFIT and DISADVANTAGE of reptiles being ectotherms (low energy demands)?
benefit: they can go without eating as much
downside: they are completely at the whim of the outside temp. & if it is too cold outside their muscles won't work b/c they can't warm themselves
147
Birds (part of reptiles) are...
ENDOthems
- like us, eat a lot of food in order to generate body heat, through metabolism (burning calories, making heat)
- expensive
- keeps body at a good temp & your muscles will always be ready for use, maintain body temp & live wherever (easier but expensive energetically)
148
What are the defining characteristics of MAMMALS?
- mammary glands - produce milk
- hair
- highly efficient kidney - allows them to be really conservative with water
- 4-chambered heart - more efficient at moving blood around & with gas exchange
- large brains - mainly b/c of neocortex (6 layers of cells on the cerebral cortex to process incoming signals)
- basically a more sophisticated brain
149
Monotremes...
lay eggs
- echidnas ("spiny anteaters") = porky pine
- duck-billed platypus
150
Eutherians (placental mammals)...
complete embryonic development in the womb (ex: "anteater" or US)
151
Marsupials begin in development in the womb, then...
crawl into pouch, attach to nipple, & complete development inside the pouch
152
What are the features of the duck-billed platypus (a true mammal)?
1. they have bills & webbed feet like ducks
2. they lay eggs
3. they're venomous
4. they produce milk but no nipples
5. they have 5 pairs of sex chromosomes
153
What do we know about hominin evolution?
- throughout evolutionary history, multiple hominin species coexisted
- today, we're the only ones left
- homo sapiens & neanderthalensis coexisted
- in the last 2-3 million years, many hominin species coexisted
154
Flatworms are the 1st animals with...
bilateral symmetry & triploblastic
155
Although flatworms undergo triploblastic development they are...
acoelomates (animals that lack a body cavity)
156
Ctenophores...
- not always radial
- have more cell types than sponges
- have a rudimentary (basic) nervous system
157
Spicules
cumulate & become the skeleton & are left behind (exoskeleton of sponges)
158
Spongocoel
cavity but not true cavity (in porifera)
159
Which phyla are the 1st eumetazoans?
cnidarians!
| - tissues! but only 2 layers
160
What is evidence for the PORIFERANS being the basal animal group?
1. their lack of body symmetry
2. the close resemblance of poriferan cells to slime molds
3. their lack of germ layers
4. the close resemblance of choanocytes to choanoflagellates
161
What are the 3 types of cnidocytes?
1. stinging --> have venom, explode & pierce their victim & inject venom into prey
2. entangling --> explode net to tangle up prey
3. gripping --> adhere to surfaces, those that walk use those to grip
162
What are the most primitive (1st) chordates (the invertebrate chordates)?
- lancelets
| - tunicates
163
What are the most primitive (1st) vertebrates?
- hagfish
| - lampreys
164
Hagfish...
- vertebrate
- eat dead & dying animals by ENTERING them
- secrete slime to suffocate predators
- ties itself into knots to escape from its own slime
165
Lampreys...
- vertebrate
- can be marine, freshwater, or either
- larvae are SUSPENSION FEEDERS (just eat stuff in water)
- most adults are PARASITES (drinking blood or eating flesh)
- a few are NONTROPHIC (don't eat b/c don't have mouths/digestive system b/c die quickly)
166
Lobe-finned fishes...
- part of jawed vertebrates (under chordates)
- fins are more lobe-like
- some are in deep seas; coelacanths
- some are in shallow, stagnant waters: the lungfishes
lungfish:
- developed true lungs (from swim bladder)
- can breath air CO2 is in short supply in shallow, stagnant water)
167
Tetrapods (the amphibians)...
- no more gills (in most adults); most larvae still need gills (live in water)
- some breathe through their skin & some have even lost their lungs
- must still lay eggs in water
168
Compare the 3 main groups of amphibians (salamanders, frogs & caecilians).
salamanders:
- some aquatic
- some terrestrial (fully or partially)
- some are legless
frogs:
- generally more terrestrial than salamanders
- completely terrestrial in some groups (toads) (some live in the desert)
caecilians:
- completely legless
- more closely related to frogs than to salamanders
169
What are the two main groups of amniotes?
- reptiles
| - mammals
170
Describe Flatworms
- 1 digestive system opening (or none in the case of tapeworms)
- true nervous systems:
- paired eyespots
- paired anterior ganglia
- segmental ganglia
- paired ventral nerve cords
- transverse nerve cords
- although they undergo triploblastic development they are ACOELOMATES (animals that lack a body cavity)
171
Describe the Planaria (rhabditophorans)
- found in pretty much any freshwater pond
- not considered "immortal", but...
- exhibit extraordinary regenerative ability
- also important in the study of regenerative medicine
- can be trained in laboratory settings!
- some reproduce asexually through FISSION or sexually
172
Describe the Trematodes (flukes) and Tapeworms (both rhabditophorans)
- both are important parasitic organisms
- tapeworms have no real digestive system, their hosts digest food from them
- (absorb our food from our intestines)
173
Gastropod group within the molluscs
("belly-foot")
| snails & slugs (marine, freshwater, & terrestrial)
174
Bivalve group within the molluscs
("two-door")
| mussels (sessile - never move again), clams (sedentary - little bit more motile), scallops (they swim! & have eyes!)
175
Cephalopod group within the molluscs
("head-food")
nautiluses, cuttlefish, squids, & octapuses
(all swimming predators)
176
What are the 2 main Annelid groups? Explain
Errantians - mostly marine with GILLS (to extract oxygen from the water)
Sedentarians - means relatively sedentary (but they wiggle & crawl, more but not very fast & active)
ex's:
- earthworms
- leeches (both blood-sucking & predatory types)
- can crawl surfaces under water & can swim a bit
- tube-dwelling worms (completely sedentary)
- permently in a tube (don't go anywhere)
- capture food as it's drifting through water (digest & absorb from combs outside)
177
Many nematodes are parasites, but...
Caenorhabditis elegans (C. elegans)
- is a perfectly benign little thing (approx. 1mm)
- lives in damp soil
- enormously important in developmental biology, genetics, neuroscience,...
- "genetic model species" (sequenced, editable genome)
- EVERY cell is mapped
- NO FEMALES!
- hermaphrodites typically self
- when male: it just goes up along the side of the hermaphrodite & then it fertilizes the egg instead of letting hermaphrodite fertilize it's own egg
- then hermaphrodite lays the fertilized egg onto the substrate
178
Why is EVERY cell mapped in the C. elegans? AND why is this possible?
- we know every single cell; where it came from, which cell divided to make that cell, we can trace the lineage of every single cell on the entire body all the way back to the egg & every single cell has a name (been labelled)
possible b/c:
- it is a small animal (approx. 1mm long)
- almost all are hermaphrodites
179
What are the 3 main groups of Arthropods?
1. Chelicerates (spiders)
2. Myriapods (centipeds)
3. Pancrustaceans (crustaceans + insects ex: butterfly)
180
What are the 3 groups of primates?
1. lemurs, lorises, bushbabies
2. tarsiers
3. antropoids (humans)
181
What are the 2 groups of anthropoids (aka simians)? under primates
1. monkeys
| 2. apes
182
What are the 2 groups of monkeys?
1. new world
| 2. old world
183
What are the 5 groups of extant apes?
1. gibbons
2. orangutans
3. gorillas
4. chimpanzees
5. hominins (humans)
184
What is the problem with the word "monkey"?
group monkeys isn't monophyletic b/c apes aren't included
185
What are Hydra and Frakenhydra (under cnidarians)?
hydra:
- named after the creature in Greek mythology: "The Twelve Labors of Hercules"
- freshwater cnidarians
- "immortal" animals - basically live forever cause they keep regenerating new pieces & keep growing
- exist only in polyp form but are not sessile...they "walk"
- only a few cell types
- so simple, they can be "rearranged" (cut them up & put them back together)
frakenhydra:
- can be cut & heads go together
- b/c they are "immortal": very valuable for studies in regenerative medicine
- "Frankenhydra" make one wonder what exactly "self" is
186
Which insects are Heminetabolous (undergo incomplete metamorphosis)?
- silverfish
- dragonflies + damselfies
- grasshoppers + crickets
- stick insects
- cockroaches
- termites
- true bugs
not monophyletic!
187
What insects are Holometabolous (complete metamorphosis?)
- beetles
- ants, bees, & wasps
- butterflies & moths
- flies
188
What are examples of Echinoderms?
- sea stars (starfish)
- sand dollars
- sea urchins
- sea lilies
- sea cucumbers
- brittle stars
189
What is unique about the SEASTARS (starfish) under echinoderms?
- crawl along rock & coral
- hunt clams (shove stomach in!)
- strong!
- they can pry open clam to inject their stomach out of their mouths & into clam & so they digest everything in clam & suck it up & move on
190
What is unique about the SAND DOLLARS under echinoderms?
- bury themselves in sand
| - eat small crustaceans, plankton, algae, & detritus
191
What is unique about the SEA URCHINS under echinoderms?
- eat algae (or sessile or very slow - moving animals)
| - very painful to step on!
192
What is unique about the SEA LILIES under echinoderms?
suspension feeders (filter out food)
193
What is unique about the SEA CUCUMBERS under echinoderms?
- eat plankton & detritus
| - some are eaten by humans
194
What is unique about the BRITTLE STARS under echinoderms?
- look like but don't act like starfish
- locomote by THRASHING ARMS about
- up to 60cm in diameter
- some bioluminesce blue or green
- suspension feeders
195
There are both invertebrate & vertebrate chordates?
yes lol
196
What does the human embryo have?
- dorsal, hollow nerve cord
- notochord
- pharyngeal slits
- post-anal tail
197
What is the function of the dorsal, hollow nerve cord? (in chordates)
connects brain with basically all other tissue
| other invertebrate phyla have ventral, solid nerve cords
198
What is the function of the notochord? (in chordates)
flexible rod for muscle attachment & support
| - in humans, only in early development & releases growth factors & goes away (not used for structure)
199
What is the function of the pharyngeal slits? (in chordates)
(filter-feeding organs)
- water goes through & the gills just grab whatever food is available in the water
- in humans it goes away
200
What is the function of the muscular post-anal tail? (in chordates)
in humans it goes away after
201
What are the lancelets?
(invertebrate chordates)
- live in marine sand
- suspension feeders
- adults have chordate features (like bilateral symmetry etc.)
202
What are the tunicates (sea squirts)?
(invertebrate chordates)
- sessile
- suspension feeder
- larvae have chordate features
- adults hare radially symmetric (novel trait, like in echinoderms)
203
Which were the 1st amniotes?
reptiles
204
What are extant groups of reptiles?
- turtles
- crocodilians (crocodiles & alligators)
- birds ("modern dinosaurs")
- lepidosaurs
- tuatara (lizard-like)
- squamates (snakes & lizards)
- ectothems (non-avian)
- endotherms (birds)
205
4 important groups of the eutherians (under mammals)?
1. Paenungulata (sub-ungulates, or "almost hooved")
- Proboscidea (ex: elephants)
- Sirenia (ex: manatees)
- Tubildentata (the aardvark)
2. Xenarthra (ex: ant eaters, sloths, armadillos)
3. Scrotifera
- Carnivora (ex: hyenas, cats, wolves, bears, raccoons, walruses, weasels)
- Cetartiodactyla (even-toed ungulates; ex: giraffes, bison, deer, cattle, whales)
4. Glires (LARGEST group of eutherians)
- Rodentia (ex: mice, rats, squirrels, beavers)
- Lagomorpha (ex: rabbits, hares)
- Primates
206
How does the animal grow if the really hard rigid shell never goes away? in molluscs
- unlike in the indiso animals, it is just added onto
- as the snail gets bigger, the shell continues coiling & secretes more & more shell & the snail shell just gets bigger (the coil just gets bigger)
- obvious in bivalves, as the animal gets bigger it just secretes more & more shell outward & the shell just gets bigger/longer
207
Chelicerates (spiders) within the arthropods:
characterizes by:
- chelicerae (appendages) usually "pincers" or "fangs"
- 2 primary body parts
1. cephalothorax (head+thorax)
2. abdomen (a lot of gut, typically no appendages off the abdomen)
2 main groups:
1. Arachnids
- scorpians
- spiders
- ticks
- mites
2. Horseshoe crabs ("living fossils") AKA haven't changed in a long time
208
Myriapods (centipeds) within the arthropods:
"many feets"
- less specialized segments
- 2 main groups:
1. Millipedes
- herbivores
- each "segment" is actually 2 fused segments
- each with 2 pairs of legs
2. Centipedes
- carnivores
- often venomous
- 1 pair of legs per segment
209
Pancrustaceans (crustaceans + insects ex: butterfly) within the arthropods:
crustaceans & insects now recognized as a single clade
| - so we made it monophyletic group
210
What are the 2 main groups of Chelicerates (spiders) within the arthropods?
1. Arachnids
- scorpians
- spiders
- ticks
- mites
2. Horseshoe crabs ("living fossils") AKA haven't changed in a long time
211
What are the 2 main groups of Myriapods (centipeds) within the arthropods?
1. Millipedes
- herbivores
- each "segment" is actually 2 fused segments
- each with 2 pairs of legs
2. Centipedes
- carnivores
- often venomous
- 1 pair of legs per segment
212
Which phyla is this?
- tube sponges
- vase sponges
- glass sponges
- ball sponges
sponges
213
Which phyla is this?
- hydras
- jellyfishes
- amenomes
- corals
cnidarians
214
Which phyla is this?
- planarians
- flukes
- tapeworms
flatworms
215
Which phyla is this?
- snails
- clams
- squids
- octopuses
molluscs
216
Which phyla is this?
- earthworms
- leeches
- tubeworms
annelids (segmented worms)
217
Which phyla is this?
- heartworm
- hookworm
- c. elegans
- t. spiralis
nematodes (roundworms)
218
Which phyla is this?
- spiders
- centipedes
- lobsters
- insects
arthropods
219
Which phyla is this?
- starfish
- sea urchins
- sea cucumbers
echinoderms
220
Which phyla is this?
- you
- me
- lancelets
- tunicates
chordates
221
Which phyla have organogenesis occur?
in ALL bilateria
222
Which phyla have neurogenesis occur?
ONLY in the chordates
223
What is the benefit of a segmented body plan?
makes development easier; requires less genetic info; each segment is modification of previous segment
224
Why is the countercurrent arrangement superior?
Ultimately, a counter-current arrangement can extract more oxygen out of the water than the alternative (doing this by maintaining a gradient along its entire length).
225
What does spiracles/tracheal respiratory system in insects do?
Spiracles along side of body open to outside world, allowing air into an intricate tracheal system that permeates the entire body. Oxygen diffuses passively from the trachea into nearby body cells.
226
If an insect is a wasp, a member of the Hymenoptera. How does this individual control whether she lays a male or female egg?
To lay a female egg, she makes it diploid by fertilizing it with a stored sperm cell. To lay a male egg, she doesn't fertilize it, leaving it haploid.
227
How is the nitrogenous waste ultimately removed from the insect body?
1. Waste products are actively transported from hemolymph into Malpighian tubules, and water follows osmotically. There's no filtration as in most animals.
2. Waste is combined with dietary waste in the digestive system.
3. Water and important molecules are recovered in the rectum.
4. Waste is eliminated out the anus.
228
Gastrulation results in the appearance of which structures or features?
- archenteron: opening that formed
| - blastopore: hole going to that opening
229
What structure is likely derived from the blastocoel?
hemocoel
230
Where does the coelom come from?
mesoderm
231
Which are important for recovering water & important solutes from the filtrate in the nephrons?
- higher osmolarity in the renal medulla than in the renal cortex
- differential osmolarity b/t the tubules & the surrounding tissue
- active transport of solutes
- passive diffusion of solutes
- passive diffusion of water
- aquaporins
