Chapter 23 Terms and Ideas Flashcards
1
Q
General Characteristics of Animals
A
- Multicellularity
- Heterotrophy
- Internal digestion
- Motility
2
Q
Hox Genes
A
specify body pattern and axis formation
3
Q
Common Ancestor of Animals
A
most likely colonial flagellated protist
4
Q
Diploblastic
A
animals have 2 cell layers—ectoderm and endoderm
5
Q
Triploblastic
A
have 3 cell layers—ecto-, endo-, and mesoderm
6
Q
Gastrulation
A
hollow ball of cells indents and forms a cavity, the blastopore
7
Q
Protosomes
A
mouth arises from the blastospore
8
Q
Deuterosomes
A
blastopore becomes the anus, mouth forms later
9
Q
Body plan
A
- Symmetry
- Body cavity structure
- Segmentation
- External appendages
10
Q
Symmetry
A
overall shape. Can be asymmetrical or symmetrical
11
Q
Radial symmetry
A
body parts arranged around a central axis
12
Q
Bilateral symmetry
A
can be divided into mirror image halves on only one plane
13
Q
Cephalization
A
concentration of sensory organs and nerve tissues at the anterior end, or head
14
Q
Circular and longitudinal muscles
A
make for more control of the animal’s movement
15
Q
Segmentation
A
facilitates specialization of body regions. Allows the animal to altar its body shape and control movement easier
16
Q
Bilateria
A
monophyletic group that includes protostomes and deuterostomes (bilateral symmetry and triploblastic)
17
Q
Eumetazoans
A
- Body symmetry
- A gut, and nervous system
- Tissues organized into distinct organs
18
Q
Sponges
A
no distinct tissue types and have hard skeletal elements called spicules
19
Q
Sponge Body plan
A
aggregation of cells around a water canal system.
Water and food particles enter through small pores and pass into the canal system where the choanocytes capture food particles
20
Q
Placozoans
A
- Four cell types; weakly differentiated tissue layers
- Flattened animals that adhere to substrates; asymmetric
- Diploblastic
- Have a swimming, pelagic stage
21
Q
Ctenophores
A
radial symmetry;
• Diploblastic
• Complete gut; feed with tentacles that discharge sticky material to trap plankton
22
Q
Mesoglea
A
gelatinous extracellular matrix found in Ctenophores
23
Q
Ctenes
A
8 comb-like plates that allow Ctenophores to move
24
Q
Cnidarians
A
- Jellyfishes, sea anemones, corals, hydrozoans
- Nearly all are marine
- Radial symmetry
25
Gastrovascular cavity (Cnidarians)
functions in digestion, circulation, and gas exchange, and as a hydrostatic skeleton
26
Polyp and Medusa Stages (Cnidarians)
Polyp means cylindrical stalk attached to substrate and medusa means free-swimming stage
27
Two Major Groups of Protosomes
lophotrochozoans and ecdysozoans
28
Arrow worms
Small marine predators of planktonic protists and small fish.
Evolutionary relationships unclear
29
Lophophore
found in Lophotrochozoans and are U-shaped ring a ciliated tentacles around the mouth (food collection or gas exchange)
30
Bryozoans
Colonial animals that live in a “house” made of material secreted by the external body wall.
Individuals are connected by strands of tissue.
Colonies form by asexual reproduction; some can be huge
31
Flatworms
Tapeworms and flukes are internal parasites, particularly of vertebrates.
• No digestive tract: they absorb digested food from gut of host
• Cause serious diseases such as schistosomiasis
• Have complex life cycles with multiple hosts
32
Rotifiers
Most are tiny, the size of protists.
• Complete digestive tract
• Pseudocoel functions as a hydrostatic skeleton
• A ciliated corona on the head sweeps food particles into mouth
33
Ribbon Worms
* Complete digestive tract
| * Rhynchocoel—fluid-filled cavity enclosing a hollow, muscular proboscis, the feeding organ.
34
Phoronids
Small, sessile marine worms that secrete tubes of chitin to live in.
Feed on suspended particles with a lophophore
35
Brachiopods
Solitary, with two-part shell—dorsal and ventral.
Lophophore is inside the shell.
Leave an excellent fossil record; were much more abundant during the Paleozoic and Mesozoic
36
Annelids
* Segmented body plan; body parts can move independently
* Each segment has a separate coelom and a nerve center (ganglion).
* Body covered by a thin, permeable body wall used for gas exchange; restricted to moist environments
37
Pogonophorans
have lost the digestive tract; they can absorb organic matter from the sediments
38
Oligochaetes
no parapodia, eyes, or anterior tentacles. Eggs and sperm are deposited outside the body, in a cocoon secreted by the clitellum
39
Parappodia
Some annelid species have outgrowths on each segment (help with gas exchange)
40
Leeches
no parapodia or tentacles
Segments at ends of body are modified to form suckers, temporary anchors that help the leech move.
Feed by making an incision in the host and injecting an anticoagulant to keep blood flowing.
Medicinal leeches are still used to reduce fluid pressure, prevent blood clotting, and prevent scarring.
41
Mollusks
The foot—a muscular structure originally used for locomotion and support for internal organs
The mantle—fold of tissue that covers organs of the visceral mass. Mantle secretes the calcareous shell
42
Chitons
have 8 overlapping calcareous plates surrounded by the girdle.
Marine; scrape algae and other organisms from rocks with a radula
43
Gastropods
Snails, whelks, limpets, slugs, nudibranchs (sea slugs), abalones
Include the only terrestrial mollusks—snails and slug
44
Bivalves
clams, oysters, scallops, mussels
Hinged, two-part shell
Some use the foot to burrow into sediment
45
Cephalopods
squids, octopuses, nautiluses
Excurrent siphon is modified to eject water from mantle for “jet propulsion.”
Ability to move rapidly makes them efficient predators
Capture and subdue prey with tentacles
46
Ecdysozoans
have a stiff external covering, or cuticle, secreted by the epidermis.
To grow, the cuticle must be shed or molted, and replaced with a newer larger one
47
Arthropods
have appendages manipulated by muscles.
Appendages are used for walking, swimming, gas exchange, food capture and manipulation, copulation, and sensory perception
48
Nematodes
Unsegmented body; thick cuticle that provides shape
Gas and nutrient exchange occurs through the cuticle and the gut.
Probably the most abundant and universally distributed animal group
49
Horsehair worms
Unsegmented; very thin
Most live in freshwater in leaf litter and algal mats.
Larvae are internal parasites of crayfish and insects.
Adults have no mouth and reduced guts; feed only as larvae, absorbing nutrients from their hosts.
50
Arthropods
ecdysozoans with paired appendages.
| Extremely diverse group, huge number of species and huge number of individuals
51
What makes arthropods successful?
segmented bodies and rigid exoskeletons
52
Onychophorans
* May be similar to the arthropod ancestor
* Segmented; with fleshy, unjointed legs
* Thin, flexible cuticle with chitin
53
Tardigrades
Fleshy, unjointed legs
Very tiny, no circulatory or gas exchange systems.
Some species live on water films on plants
54
Chelicerates
appendages modified into mouth pieces that are used to grab prey
55
Arachnid
spiders, scorpions, harvestmen, mites, ticks
Simple life cycle; miniature adults hatch from internally fertilized eggs and begin independent lives almost immediately.
Some mites and ticks are parasites of animals, and vectors of diseases.
Spiders are important terrestrial predators; hollow chelicerae are used to inject venom into prey
56
Myriapods
centipedes, millipedes
• Have mandibles for chewing and biting as well as grasping prey.
• Segmented trunks with many pairs of legs
Centipedes—one pair of legs per segment; prey on insects and other small animals.
Millipedes—two pairs of legs per segment; scavenge and eat plants
57
Hexapods
insects and their millions of species
Insect bodies have three regions—head, thorax, and abdomen.
One pair of antennae on head; 3 pairs of legs attached to the thorax.
In most groups the thorax also bears 2 pairs of wings.
External mouthparts
58
Pterygote
(winged) insects—2 pairs of wings, one or both pairs have been lost in some groups.
59
Neopterans
insects that can tuck their wings out of the way upon landing.
60
Deuterostomes
* Triploblastic and coelomate
* Internal skeletons
* Includes many large animals—including humans
* Complex behaviors are especially well developed in some groups
61
Echinoderms
sea stars, sea urchins, sea cucumbers, crinoids
Only 6 of 23 fossil groups survive today.
Nearly all marine
Change from a bilaterally symmetrical larva to an adult with pentaradial symmetry
62
Hemichordates
have three body parts:
• Proboscis
• Collar
• Trunk
63
Notochord
has a core of large cells with fluid-filled vacuoles, making it rigid but flexible
64
Vertebral Column
replaces the notochord during early development. It is jointed and dorsal
65
Key features of vertebrates
* Anterior skull with a large brain
* Rigid internal skeleton supported by the vertebral column
* Internal organs suspended in a coelom
* Well-developed circulatory system with a ventral heart
66
Chondrichthyans
sharks, skates, rays, chimaeras
| Skeleton of pliable cartilage; leathery skin
67
Sarcopterygians
coelacanths, lungfishes, tetrapods
Jointed appendages joined to the body by a single enlarged bone.
Coelocanths were thought to have become extinct 65 mya, but living ones were found off South Africa in 1938
68
Tetrapods
four-legged vertebrates
69
Amphibians
caecilians, frogs and toads (anurans), salamanders
| Most live in moist environments—they lose water easily through the skin, and eggs dry out if exposed to air
70
Factors of the decline of amphibians
* Habitat destruction
* Increased UV radiation due to ozone layer thinning
* Air pollution
* Agricultural pesticide pollution
* Pathogenic chytrid fungus.
71
Amniotes
Many adaptations led to success on land:
• Amniote eggs
• Tough skin with scales and other modifications to prevent drying.
72
Amniote eggs
* Impermeable to water;
* Leathery or calcium-impregnated shells prevent water loss but allow gas exchange;
* Store food for the embryo in the form of yolk
73
Crocodilians
crocodiles, caimans, gharials, alligators
• Live in tropical and warm temperate environments.
• They build their nest on land or floating piles of vegetation. Heat from decaying organic matter warms the eggs.
• All are carnivorous.
74
Key features of mammals
* Sweat glands
* Mammary glands
* Hair
* Four-chambered heart that completely separates oxygenated from deoxygenated blood
* Eggs are fertilized, and embryos start development, within the female body
75
Prototherians
type of mammal (lack a placenta and lay eggs)
76
Therians
all other mammals, includes marsupials and eutherians
| Marsupials carry their young in pouches
77
Eutherians
20 major groups
• Rodents: teeth adapted for gnawing; largest group
• Bats: flying mammals
• Moles and shrews: 3rd largest group
