Animal evolution Flashcards
1
Q
What are the majority of animal species?
A
insects
2
Q
What do they ectotherm and endoderm turn into?
A
Ectoderm: skin
Endotherm: digestive system
3
Q
Why does the fossil record have holes in it?
A
things only fossilize under specialized conditions
4
Q
What were the contributing factors to the cambrian explosion?
A
- presence if atmospheric oxygen
- evolution of hox genes
- predator-prey relationships
5
Q
Metabolic classification of animals
A
heterotrophs
6
Q
Structure of animals
A
- Have nervous system and muscle tissue
* bodies are held together by structural proteins(collagen)
7
Q
Sexual life cycles of animals
A
most animals reproduce sexually with the diploid dominant stage dominating the life cycle
8
Q
Blastula
A
Hollow sphere with an outer layer of cells that forms after the zygote undergoes cleavage
9
Q
Gastrulation
A
invagination process that the blastula undergoes resulting in embryonic tissue layers and a gastrula
10
Q
Hox genes
A
Position genes that regulate the development of body form of embryos, highly conserved genes
11
Q
Ways a fossil may be formed
A
- Permineralization
- molds, casts, impressions
- Whole organism is preserved
12
Q
Mesozoic era
A
- Dinosaurs were dominant
- Coral reefs emerged, becoming important ecological niches
- extinction of dinosaurs at the end of this era opened up niches for animals
13
Q
When did modern mammals/insects diversify?
A
cenozoic era
14
Q
Grade
A
group of animal species that share the same level of organizational complexity
Based on
- Presence/absence of different tissues
- body symmetry
- presence/absence of true body cavity
- Patterns if embryonic development
15
Q
What is believed to be the common ancestor of all animals?
A
choanoflagellates
16
Q
What are levels of organization and what do they show?
A
They are feature of body plans and there are cellular, tissue, organs, etc. levels
17
Q
How are different tissues isolated?
A
membranous layers
18
Q
Radial symmetry
A
Parts of an animal radiate from the center. Any imaginary slice through the center divides it in half
19
Q
Bilateral symmetry
A
Has a right and left side. One cut divides organism into mirror images
20
Q
Cephalization
A
development of the head
21
Q
What do animals with bilateral symmetry have
A
- Dorsal(top) side and ventral(bottom) side
- A right and left side
- Anterior(head) and posterior(tail) end
- cephalization
22
Q
Advantage of putting sensory organs in the head of an animal
A
Allows organism to process environment asap
23
Q
What is true of animals with gastrovascular cavities?
A
Their mouth and anus or the same thing
24
Q
Difference between complete and incomplete gut
A
Incomplete has one mouth/anus, complete has a separate mouth and anus
25
What leads to the formation of the blastula
The zygote undergoing cleavage
26
What is the result of the blastula undergoing gastrulation
Formation of embryonic tissue layer and a gastrula
27
Animal embryo characteristics
Form germ layers, embryonic tissues, ectoderm, endoderm and mesoderm
28
Diploblastic and triploblastif animals
Diploblastic: 2 germ layers
Triploblastic: 3 germ layers, may have body cavity
29
Schizoceolous
Solid masses of mesoderm split and form coelom
30
Entercoelous
folds of archenteron for coelem
31
Purpose of mesoderm in triploblastic animals
Splits and forms coelom, creates space in blastula and blastopore opening
32
what are exoskeletons made of?
chitin
33
Archenteron
folds in the blastula
34
coelom
a true body cavity derived from mesoderm
35
Coelmates
have true coelem lined by mesoderm tissue. Order of tissues from the outside to inside is Ectoderm, mesoderm, coelem, mesoderm, endoderm. Example is annelids
36
pseudocoelom
body cavity derived from the blastocoel rather than mesoderm. Example is nematodes. Order is body covering ectoderm, muscle layer mesoderm and digestive tract endoderm
37
acoelmates
organisms without body cavities between digestive tract and outer body well. examples are flatworms. Order is body tissue(ectoderm, mesoderm tissue, endoderm digestive tract
38
Hydrostatic skeleton
Turgid column of liquid within body space, provides rigity
39
Segmentation vs strobilization
Segmentation: necessary part of the body for organism survival
Strobilization: Purse like addition for reproduction, segment breaks off
40
Protosome
Cleavage is spiral and determinate, schizocoelous development, blastopore becomes mouth
41
Deuterosome
Cleavage is radial and indeterminate, entercoleous development, blastopore forms anus
42
Indeterminate cells
cell or cell group is not yet specialized
43
Schizocoelous development vs Entercoelous development
Schizocoelous: Solid masses of mesoderm split and form coelom
Entercoelous: folds of archenteron form coelom
44
what type of development was multicellularity
synapomorphy
45
Which animal is basal?
sponges(agreed upon)
46
Eumetazoa
agreed upon clade of animals with true tissues
47
Bilaterian disagreement
The morphology-based tree divides bilaterians into deuterosomes and protosomes while the molecular tree divides protosomes in ecdysozoans and lophotrochozoans
48
Ecdysozoans
Shed exoskeletons through a process called ecdysis
49
what do lophotrochozoans have that other phyla dont
They have a feeding structure called a lophophore while other phyla go through a distinct larval stage called a trochophore
50
Sponge phyla
porifera
51
What lineage to sponges resemble and how do we know?
Sponges resemble choanoflagellates the most based on molecular evidence and morphology of their choanocytes
52
What are the germ layers of sponges like?
loose federations of cells, they are not really tissues because the cells are relatively unspecialized
53
Characteristic of sponge cells
no muscle or tissue, individual cells can react to the environment
54
Spongocoel
central cavity of sponges where water is drawn into through pores
55
Osculum
Larger opening in sponges that water flows out of
56
What are characteristics of complex sponges?
They contain branched canals and several oscula
57
Choanocytes
Collar cells lining the spongocoel that create a flow of water through the sponge with their flagella and trap food with collars
58
How do sponges reproduce?
Asexually via regeneration from fragments broken off parent sponge
59
How do sponges repair/heal and why is this special?
Regeneration, sponges can go through extensive regeneration compared to other animals
60
sessile
anchored(sponges)
61
Nervous system in sponges and cnidarians and ctenophores?
Sponges: not present
Cnidarians and ctenophores: present
62
Cells around each layer bound together in sponges and cnidarians and ctenophores?
Sponges: No except for homoscleromorphs, they have basement membranes
Cnidarians and ctenophores: inter-cell connections and basement membranes
63
number of cells in middle jelly layer in sponges and cnidarians and ctenophores
Sponges: many
Cnidarians and ctenophores: few
64
Can cells in outer layers move inwards and change functions in sponges and cnidarians and ctenophores?
Sponges: Yes
Cnidarians and ctenophores: No
65
Oldest eumetazoan clade
Radiata: animals with radial symmetry and diploblastic embryos
66
What clade do most animal phyla belong to?
bilateria
67
Deuterostomia
Vertebrates and some other animal phyla
68
Cnidaria
Very old group, radial symmetry, sac with a central gastrovascular cavity, cnidocytes, part of eumetazoa. Have diversified into both sessile and floating forms of coral, jellies and hydras. Have a single opening that functions as mouth and anus
69
Visceral
mass in the center of some animals that serves as the gut that is surrounded by the mantle
70
Polyp/Medusa
Variations of the body plans of cnidarians. The polyp is sessile, whereas the medusa is the typical floating jellyfish
71
cnidocytes
Unique cells that function in defense and capture of prey in the tentacles of cnidarians
72
What kind of predators are cnidarians?
carnivores
73
Ctenophora
Phylum of comb jellies that possess rows of ciliary plates and adhesive colloblasts, They superificially resemble cnidarian medusas, but the relationship between the two is uncertain. Ctenophora means "comb bearer", have 8 rows of comb-like plates composed of fused cilia. Most comb jellies have a long pair of retractable tentacles
74
Variety in ctenophora
some species are marine, some are spherical or ovoid, some are elongate and ribbon like
75
Colloblasts
adhesive structures that secrete a stick thread to capture food in the tentacles of ctenophora
76
What type of development do animals in bilateria have?
triploblastic
77
Platyhelminthes
live in marine, freshwater, and damp terrestrial habitats. They are flattened dorsoventrally and have a gastrovascular cavity.
78
Flatworms
triploblastic development, acoelmates
79
Tapeworms
Parasitic, adult tapeworms live mostly in invertbrates/humans. They have suckers/hooks on their head/scolex anchor them in the digestive tract of the host. They have proglottids. They absorb food from hosts
80
Proglottids
sacs of sex organs that lie posterior to the scolex in tapeworms
81
Lophophore
horse-shoe shaped, suspended feeding organ with ciliated tentacles
82
Ectoprocts
Colonial animals that superficially resemble plants, have lophophores(lophophorates)
83
Phoronids
Tube-dwelling marine worms, range 1mm to 50cm in length, have lophphores(lophophorates)
84
Why are molecular trees used more than morphological tress?
They have synapomorphies that tie morphologies together better than morphological trees
85
Brachiopods
Superifically resemble clams and other hinge celled molluscs
86
Difference between brachiopods and clams
the shells of brachiopods are dorsal/ventral and in clams theyre lateral
87
Molluscs
visceral mass, muscular foot and mantle, most are marine and some are terrestrial or freshwater, soft bodies, most are protected by a hard shell, gonads loacated in visceral mass, have trochophore stage
88
Annelids
segmented worms with bodies composed of series of fused rings
89
Nemotades
non-segmented pseudocoelmates, covered by tough cuticle/exoskeleton, crops are rotated because of certain nematodes being parasites to specific crops, found in moist habitats, cylindrical bodies
90
Why are nematodes and arthropods next to each in the molecular tree?
both have tough exoskeletons
91
Arthropods
segmented coelemates, found in nearly all habitats, 2/3 of animals are arthrpods, appendeges are modified for many different functions, open cirulatory system
92
Early arthrpods vs modern arthropods
early arthropods showed little variation from segment to segment, modern arthrpods and very diverse
93
Organ evolution of arthropods
they have evolved for specialized gas exchange
94
Hemolyph
Fluid that circulates to surrounding tissues and organs in arthropods, part of open circulatory system
95
What relationship did insects and angiosperms have and what did it result in
they had a coevolutionary relationship, resulting in a vast growth in diversity for both groups
96
Echinodermata
modified radial symmetry with 5 parts, larvae are bilateral, adults are secondarily symmetrical, no cephalization or brain, simple nervous system, hard endoskeleton covered in thin layer of skin, hard calcareous plates, prickly skeletons and spines with various functions, detachable body parts that will regenerate, external fertilization
97
Water vascular system
tube feet functions in feeding, gas exchange, and feeding in echinoderms
98
How do echinoderms respirate/excrete?
diffusions, they have no excretory organs
99
Which groups are humans apart of?
Deuterostomes, chordata
100
Reproduction of starfish
Both sexes release clouds of gametes into the water and fertilization occurs in the water, triggered mostly by water temp, as well as lighting and moon phases
101
Subphyla of chordata
Urochordata/tunicates: Sessile adults with only pharyngeal slits, exhibit all 4 innovations at tad-pole like larvae, use siphons to filter feed, enclosed in tunic, rudimentary circulatory system, simple nervous system, mostly hermaphroditic
Cephalochordata: look like urochordata larvae as adults, marine filter feeders, exhibit all 4 innovations, gas exchange across body surface, mostly sessile but they can leave burrow and swim
102
Chordata innovations
1. Notochord(single flexible rod)
2. Dorsal hollow nerve chord
3. Pharyngeal slits
4. Post anal tail
These are all exhibited at some time during chordata development
103
Craniates
have cranium and neural crest and at least 2 Hox gene clusters, have a head
104
Neural crest
embryonic cells that will disperse throughout the embryo contributing to the development of the skeleton, nerves, jaws, and teeth, unique to craniates, gave rise to bones, cartilige and other structures,
105
Effects of evolution of a head in craniates
allowed chordates to become active predators
106
Hagfish
Modern craniates, jawless, cartilege skull, axial cartilege rod derived from notochord, good sense of smell, produce slime as defense,
