Invertebrates Flashcards
1
Q
Key characteristics of Kingdom Animalia
A
- Eukaryotic
- Heterotrophic (use pre-formed organic materials as energy and carbon source)
- Multicellularity
- No cell wall
- Motile at some stage in their life
- Somatic (body) cells are diploid (2n)
- Diplontic life cycle
2
Q
Modes of feeding
A
- Predators
- Herbivores
- Filter feeders
- Parasites
- Detritivores (consumes decomposing plant and animal matter, also feces)
- Omnivore
3
Q
Advantages of multicellularity
A
- Cells can be specialized to carry out specific functions
- Organisms have a longer lifespan
- Organisms can grow in size (high surface area - increased surface area with little volume)
4
Q
What are tissues?
A
Groups of similar cells organized into a functional unit. Tissues can function together as organs.
-muscle
-nervous
-epithelial
-connective
5
Q
How did animals adapt to no cell wall?
A
Structural support like
-hydrostatic skeleton
-exoskeleton
-endoskeleton
6
Q
Hydrostatic Skeleton
A
Muscles contract against fluid-filled cavity.
-Organisms perform simple but efficient movements
-Limited possibility for the attachment of arms
-dependence on a humid environment (prevents drying out)
7
Q
Exoskeleton
A
-firm, rigid
-non-living covering
-made of chitin and CaCO3
-doesn’t grow with the animal
-molting
-Ecdysozoa (Nematodes and Arthropods) (molting animals)
8
Q
Endoskeleton
A
-rigid structure inside the body
-internal support
-Vertebrates (living tissue)
-some invertebrates (non-living structure)
9
Q
What is the advantage of motility?
A
-reduces competition
-enhances genetic diversity
-expands distribution range
10
Q
Haplontic
A
Haplontic organism’s lifecycles are dominated by a 1n (haploid) stage[s]. Their gametes are 1n and then after fertilization, 2n zygotes are created. Then through meiosis, 1n spores are created. The Mature organism is 1n.
11
Q
Alternating life cycle
A
An organism will alternate between haploid and diploid stages. Gametophytes are the stage during 1n living then 1n gametes are produced. Through fertilization, 2n zygotes are created that grow up into Sporophytes (2n). Through meiosis, 1n spores are created.
12
Q
Diplontic
A
Diplontic organisms’ lifecycles are dominated by a 2n stage[s]. Gametes are the only 1n stage.
13
Q
Cambrian explosion
A
-rapid diversification
-new phyla formed
14
Q
Evidence that animals are monophyletic
A
-similar gene sequencing
-hox genes
-similar extracellular matrix molecules (collagen fibers, proteoglycan complex)
-unique types of junctions among cells
15
Q
Types of junctions between cells
A
Tight junctions: seal cells together (epithelial tissue)
Desmosomes: connect the cytoskeleton of cells (epithelial tissue)
Gap junctions: act as channels between cells (muscle and nerve tissue)
16
Q
Major processes during embryonic development
A
- Cleavage: multiple rounds of rapid cell division
- Gastrulation: in-folding, invagination (forming embryonic tissue layers)
- cellular differentiation: the immature cells take on individual characteristics and reach their mature (specialized) form and function
17
Q
Blastopore
A
After gastrulation (invagination), an opening is created that acts like a mouth in protostomes or an anus in deuterostomes.
18
Q
Blastocoel
A
After gastrulation, a fluid-filled cavity is created.
19
Q
Archenteron
A
After gastrulation, an “open cavity” is created on the inside. This cavity acts as a gut, a digestive space.
20
Q
Germ layers during embryonic development
A
- Ectoderm: the outer layer surrounding the cell. Becomes the epidermis of the nervous system.
- Endoderm: the inner layer surrounding the archenteron. Surrounds the digestive and respiratory tracts.
- Mesoderm: forms most internal organs like muscles, skeletal system, and part of the gonads.
21
Q
Diploblastic
A
Organisms with 2 germ layers, the ectoderm and endoderm.
22
Q
Triploblastic
A
Organisms with 3 germ layers, the ectoderm, mesoderm, and endoderm.
23
Q
Types of body symmetry
A
- Asymmetrical: no symmetry (some sponges)
- Radial Symmetry: Body can be divided into equal halves from many angles.
- Bilateral Symmetry: A single axis divides the body into equal halves. Has a midsagittal plane down the middle of the eyes.
24
Q
Porifera
A
Sponges are sessile as adults and motile as larvae. They have specialized cells but no true tissues or organs. Have an endoskeleton. They are filter feeders utilizing a strong water current system. Reproduce asexually and sexually, most species are hermaphroditic.
25
Body wall of a sponge
There are 3 main layers:
Exterior: flat epidermal cells
Middle: **Mesohyl** with ameboid cells embedded in a jelly estracellular matrix. Contains endoskeleton that is made up of Spicules and fibers.
Inner: Choanocyte cells with a collar and flagella
26
Porifera asexual reproduction
-Fragmentation (external budding that's not self-induced when a portion of the sponge breaks off and then reproduces into a new organism)
-**Gemmules** (internal budding, a collection of a few different types of cells that are enclosed by protective covering, acts as a resting stage and when ready make clones of parent)
27
Porifera sexual reproduction
Typically hermaphroditic but not able to self-fertilize. Can only make one type of sex hormone at a time. They broadcast all sperm at once.
28
Cnidarians
Jellyfish and sea anenomes. Diploblastic, radial symmetry, acoelomate, simple tissues. Body orientation: polyp (sessile) with their mouth facing upwards or medusa (motile) with their mouth facing the ground. Extracellular digestion in gastrovascular cavity. A simple nerve net, sensory information from all directions.
29
What are the 4 types of Cnidarians?
1. Hydrozoa
2. Scyphozoa
3. Cubozoa
4. Anthozoa
30
Hydrozoa
-freshwater
-most non medusa stage
-moves by gliding, somersaulting, or floating
-colonial polyps specialized for different functions
-tentacles contain cnidocytes
31
Scyphozoa
-true jellyfish
-contain nematocysts
-symbiotic algae in tentacles to get O2 and nutrients
32
Cubozoa
-Box jellyfish
-cube-shaped medusa
-potent toxins
33
Anthozoa
-sea anemones and some coral
-no medusa phase
-larvae develop directing into another polyp
-retract or expand tentacles for defense or prey-catching
-have cnidocytes
-mutualistic relationships with some fish and shrimp and dinoflagellates
34
Coelomate
Mesoderm lines the entire cavity as a "peritoneum". Annelids, Mollusks, Arthropods, Echinoderms, and Chordates.
35
Pseudocoelomate
"false coelom". Mesoderm lines the outside of the pseudocoel. Nematode, Rotifera.
36
Acoelomate
No body cavity, solid except digestive space. Flatworms (Platyhelminthes).
37
What are the two ways to make a coelom?
1. Schizocoely: splitting within the mesoderm (Protostomes, mouth forms from blastopore)
2. Enterocoely: Mesoderm forms pockets from the gut (Deuterostomes, anus forms from blastopore)
38
Platyhelminthes
Triploblastic, bilateral symmetry, acoelomate, aquatic or terrestrial (moist) habitat, free-living scavengers or parasitic. Cephalization with 2 longitudinal nerve cords running down the body, and 2 cerebral ganglia (a primitive brain).
38
Lophotrochozoa
Rotifers, Platyhelminthes, Annelids, Mollusks. A diverse group of phyla with similar DNA sequences (monophyletic group). They are protostomes, triploblastic, with bilateral symmetry.
39
Cephalization
The concentration of neurons and sensory structures at the anterior end that enables directed locomotion.
40
What are the 4 types of Platyhelminthes?
Free-living: Turbellaria
Parasitic: Monogenea, Trematoda, Cestoda
41
Turbellaria
Free-living, ability to regenerate body, anterior end always a head, reproduce asexually by fission or sexually, most are hermaphroditic.
42
Monogenea
Ectoparasites, flat body w/ suckers, attach themselves to host, no intermediate host needed.
43
Trematoda
Endoparasites, reproduce sexually in human host, intermediate host needed.
44
Cestoda
Tapeworms, endoparasites, in the gut of vertebrates, no mouth or digestive system so instead have specialized epidermis for nutrient absorption, intermediate host needed. Protective cuticle around embryos and terminal proglottids (male and female organs) break off (possibility to self-fertilize.
45
Segmentation
The division of some animal body plan into a series of repetitive segments. The advantages are:
1. Multiple copies of organs, structure (nephridia, parapodia)
2. efficient nervous control (ganglion in each segment, faster responses, efficient localized movement)
3. Increases body size by unit repetition
4. regeneration
45
Trochophore Larva
A type of larva common to marine Mollusks, marine Annelids, and several other phyla from the clade Lophotrochozoa.
45
Nephridia
An invertebrate organ which occurs in pairs and performs a function similar to the vertebrate kidney, removing metabolic waste.
46
Annelids
Segments are similar but can be modified (differentiation of the gut), lives in aquatic or terrestrial (moist) environments, coelom as a hydrostatic skeleton. Respiratory through skin (epidermis) or gills. Closed circulatory system.
47
Closed circulatory system
Advantages:
-Improved exchange between deeper tissue and surface (O2, CO2)
-faster transport of nutrients and gases
-permits development of a thicker body (free of diffusion limit)
Disadvantage:
-requires more energy for distribution than an open system
48
What are the 3 types of Annelids?
-Polychaeta
-Clitellata
-Echiura & Sipuncula
49
Polychaeta
-mainly marine
-detritivores, filter feeders
-parapodia (Muscular flaps with setae, locomotion, respiration)
-separate sexes, external fertilization
-trochophore larvae
50
Oligochaeta
-terrestrial (few aquatic)
-no parapodia, few setae
-detritivores
-hermaphroditic
-clitellum (secrets a cocoon for embryo development)
-no specialized larval stage
51
Mollusca
-terrestrial or aquatic
-bilaterally symmetric
-triploblastic
-protostomes
-reduced coelom
-distinct body plan (foot, visceral mass, mantle that acts as gills or lungs)
-radula (except bivalves)
-trochophore larvae
-open circulatory system (except for cephalopods)
51
Polyplacophora
-segmented shell (8 overlapping plates)
-herbivores
-radula scrapes algae and bryozoans
-separate sexes
-external feralization
-trochophore larva
-gills in mantle
52
Bivalve
-two hinged shells
-mantle cavity modified by siphons
-siphons, water flows in and across gills to get filtered
-enlargement of gills
-relatively sessile
-filter feeders
-no radula
-dioecious or hermaphroditic
-broadcast sperm and eggs into the water (external fertilization)
-trochophore larva
53
What are the 4 types of Mollusks?
-Polyplacophora
-Bivalvia
-Gastropoda
-Cephalopoda
54
Gastropoda
-terrestrial or aquatic
-shelled or shell-less
-reproduce sexually or asexually
-dioecious or hermaphroditic
-veliger larvae
-torsion, twisting of body 180 rotation
-coiling of the visceral mass
55
Cephalopoda
-subdivided foot, into arms and tentacles
-enlarged head
-reduced shell
-suckers or hooks on arms/tentacles
-excellent advanced vision
-complex behavior (inking)
-separate sexes with elaborate courtship
-internal fertilization
-no trochophore larva
56
Ecdysozoan
A group of protostomes, including Arthropoda and Nematoda (as well as Tardigrada + Onychophora), defined by phylogenetic reconstruction from RNA. Animals grow by ecdysis, molting their exoskeletons.
57
Tagmosis
The evolutionary process that creates tagma by modifying and fusing segments
58
Cryptobiosis
A physiological state in which metabolic activity is reduced to an undetectable level without disappearing altogether. It is known that certain plant and animal groups adapted to survive long periods of extremely dry conditions.
59
Nematoda
Elastic cuticle is molted and used as protection. Pseudocoelomates, unsegmented, elongated, circular in cross-section, feed on detritus + bacteria + fungi, some parasitic.
60
Tardigrada
-water bears or moss piglets
-small and segmented
-8 legs
-marine, freshwater, semi-terrestrial (moist)
-feed by sucking liquid from plants and animals, some detritivores
-cryptobiosis
61
Onychophora
-segmented
-lobe-like appendages
-terrestrial, humid environments
-nocturnal
62
Arthropoda
-segmented body plan (head, thorax, abdomen) with specialized regions and fused to form tagma
-jointed appendages (biramous, branched, or uniramous, unbranched)
-highly developed sense organs (highly cephalized)
-open circulatory system with 1 chamber heart with pores (ostia) that pumps hemolymph into hemocoel, a 1-way bloodstream
-reduced coelom (Hemocoel)
-non-living exoskeleton secreted by epidermis
-exoskeleton made of chitin, a protein, and CaCO3
-molt their exoskeleton (insects stop molting as adults, crustaceans continue as adults)
-all environments
-specialized mouth parts for feeding
63
What are the advantages to arthropods exoskeleton?
-physical support and protection
-place for muscle attachment
-faster locomotion
-opportunity to change morphology between larval and adult stages (metamorphosis)
-location of pigments
64
What are the disadvantages of the arthropod exoskeleton?
-inflexible and heavy
-exoskeleton cannot continue to grow in size and must be molted
-requires energy to form and shed
-respiration through skin in most cases is not possible, the need for spiracles (pores) and tracheae (tubes)
65
Incomplete metamorphosis
Eggs -> Nymph -> Nymph -> Adult
-termites, praying mantis, cockroaches
-gradual change in form
-3 stages, no resting stage
-often no habitat change
66
Complete metamorphosis
Eggs -> Larva -> Pupa -> Adult
-butterflies, moths, beetles, wasps, ants, fleas
-abrupt change in form
-4 stages, pupa is a resting stage
67
What causes molting in arthropods?
In insects, metamorphosis depends on the interaction hormones:
-PTTH (produced and stored by brain, controls activity of prothoracic glad which secretes ecdysone)
-Ecdysone (produced by prothoracic gland, secreted into blood, transported to target cell in epidermis)
A juvenile hormone is secreted in the beginning stages of life as well as ecdysone, the declining release of juvenile hormone while ecdysone is being released causes metamorphosis.
68
Respiratory system in insects
No gills or lungs, instead tubular tracheae with holes (spiracles) that help carry O2 to body cells.
69
Respiratory system crustaceans
Gills in either the thoracic cavity or appendages, O2 is pulled into the bloodstream as water is passed over the gills.
70
Respiratory system in chelicerates
Some have tracheae + spiracles, or book gills, or book lungs.
71
Phenotypic plasticity
The ability of one genotype to produce more than one phenotype when exposed to different environments.
72
Parthenogenesis
A form of asexual reproduction in which the embryo develops without fertilization from sperm. Some species reproduce exclusively by parthenogenesis (like bdelloid rotifers), while others can switch between sexual reproduction and parthenogenesis.
73
Notochord
An elastic rod-like structure derived from the embryonic mesoderm and found in many deuterostome animals. Species that have a notochord at any stage in their life cycle (along with other features) is, by definition, a chordate. It develops dorsal to the gut tube and ventral to the neural tube.
74
What are the 4 main Arthropods?
-Myriapods
-Chelicerates
-Crustaceans
-Insects
75
Myriapods
-2 body regions (head with antenna and 2 part jaw and trunk)
-Carnivores or detritivores and herbivores
-1-2 pairs of appendages per segment
76
Chelicerates
-2 body regions (cephalothorax (appendages) and abdomen)
-no jaw and no antenna
-separate sexes
-6 pairs of appendages ( 1- chelicerae (fangs), 2- pedipalps (pinchers), 3, 4, 5, 6 - walking legs)
77
Crustaceans
-dominantly marine, some freshwater & terrestrial
-Head + thorax (cephalothorax) + abdomen
-appendages off each segment
-separate sexes within internal fertilization, few hermaphroditic
-few alternate between asexual and sexual reproduction
78
Cyclical parthenogenetic life style
-During favorable conditions: a parthenogenetic cycle is undergone where diploid cells develop into identical daughters
-During unfavorable conditions: a sexual cycle will occur where the mom can produce a genetically identical son and haploid female eggs, the eggs get fertilized by the male and stay dormant until favorable hatching conditions
79
Obligate parthenogenetic life cycle
-Always produce diploid eggs
-During favorable conditions: a parthenogenetic cycle is undergone where diploid cells develop into identical daughters
-During unfavorable conditions, the mom will produce diploid eggs that dont need fertilization, can still produce sons
80
Insects
-mostly terrestrial or aquatic, few marine
-3 body regions (Head with antenna, thorax with 3 pairs of walking legs and possible wings, abdomen)
-unique external mouthparts
-wings evolved form gills of crustaceans
-separate sexes with sexual reproduction
-metamorphosis
-important ecosystem services (pollinators, decomposers, dispersal agents)
81
Echinoderms
-deuterostomes
-triploblastic
-complete digestive tract
-coelomate
-pentaradial symmetry, bilateral stage during larvae
-strictly marine, deep ocean
-diverse modes of nutrition
-separate sexes with sexual reproduction
-external fertilization
-regenerate lost tissue
-water vascular system
-hard endoskeleton (CaCO3 plates and spines, continuous growth)
-Hemal system (no true circ. system)
-lost traits that other deuterostome shave: segmentation, cephalization, bilateral in adult
82
What are the 5 main Echinoderms?
-Crinoidea
-Asteroidea
-Ophiuroidea
-Holothuroidea
-Echinoidea
83
Crinoidea
-sea lilies and sea feathers
-suspension feeders
-mid Cambrian
84
Asteroidea
-sea stars
-often predators, agile
-secret enzymes to digest prey, engulf partially digested prey
85
Ophiuroidea
-brittle stars
-long arms connected to central disk
-arm spines
-filter feeders, predators, detritivores
-deep sea
86
Holothuroidea
-sea cucumber
-mainly detritivores, scavengers, filter feeders
-reduced endoskeleton
-5 rows of tube feet
87
Echinoidea
-sea urchin and sand dollars
-distinct fused plates - endoskeleton
-pentaradial symmetry
-spines for locomotion and defense
88
Hirudinea
-ectoparasites
-no setae
-hermaproditic
-no specialized larvae stage
-medical uses
