Invertebrate Flashcards
What are the three domains of life?
Bacteria, Archea, Eukarya
What are the 7 animal characteristics? Tell me about them.
- Eukaryotic (nucleus, membrane-bound organelles, cytoplasm)
- Heterotrophic (different forms of feeding)
- Multicellularity
- No cell wall
- Motile at some life stage
- Body cells are diploid (2N)
- Animals are diplontic
What does it mean for an animal to have multiple cells?
1) cells can become specialized to carry out specific functions
2) organisms can have longer lifespan
3) can grow in size
what are the three types of structural support for animals?
1) hydrostatic skeleton (worms, shell-less snails) (just body) (muscles contract against fluid filled cavity)
2) exoskeleton (snails, outside shell)
3) endoskeleton (on inside) (sponges)
what is the reproduction process for animals?
1) meiosis (sperm and egg)
2) fertilization
3) 2N- zygote forms
4) mitosis
What are colonial choanoflagellate protists?
- closest living relative to ancestral animals
- marine
What is the Cambrian explosion?
rapid diversification, many new phyla formed
What are the three pieces of evidence that shows animals are monophyletic?
1) similar gene sequences
2) similar extracellular matrix molecules
3) unique types of junctions among cells
What are the three junctions among cells for animals?
1) tight junction (seals cells together, epithelial tissue)
2) desmosome (connects the cytoskeleton of cells)
3) gap junction (channels between them)
What are ecdysozoans?
a group of animals that grow by ecdysis which is the moulting of their exoskeleton (sheding )
What is coelom?
Internal, fluid filled body cavity, lined up with mesoderm (place for nutrient and oxygen exchange)
What are Hox genes?
group of related genes that specify regions of body, plan along the head-tail axis of animals.
What are the two major processes of embryo development?
1) cleavage (rapid multiple rounds of cell division, forming many cells from one)
2) gastrulation (in-folding forming of embryonic tissue layers)
- first cleavage happens, starts are zygote, 2 cell stage, 8 cell stage, solid ball of cells formed, then form layers called Germ layers
What are the 3 types of germ layers?
1) ectoderm (outer layer, epidermis, nervous system)
2) endoderm (inner, digestive, respiratory tract)
3) mesoderm
Compare Diploblastic Vs Triploblastic
- Diploblastic= 2 germ layers, middle skin (mesoderm, internal organs, muscles, skeletal system)
- Triploblastic= 3 layers, they have archenteron (digestive space) and blastopore (mouth and anus)
What are the three types of body symmetry for animals?
1) asymmetrical - no axis, divides body equally halves
2) radial symmetry - along one plane, can be cut into halves from many angles
3) bilateral symmetry - equal halves from single axis
What is filter feeding (sponges)?
Water and food particles go in via spores and then out of the water canal
What are the three support structures of sponges?
1) Extra cellular matrix (non-cellular, collagen and glycoproteins)
2) spongin (protein fibres, flexible support)
3) spicules (CaC03, Si02, provides rigidity)
What are the two types of asexual reproduction for sponges?
1) fragmentation (external budding, not self-induced, brought on by waves or predators)
2) internal budding (clone of parent)
What is the process of Hermaphroditic (sexual production for sponges)?
sperm and eggs produced in choanocytes or amoebocytes, the sperm is trapped by females and fertilized and then developed in the extracellular matrix, larvae released and it settles
What does cephalization mean?
the concentration of sense organs, nervous control at the anterior end of the body, forming head and brain.
What does protostome mean?
mouth appears before anus during development, coelom forms as a splitting from mesoderm.
what does deuterostome mean?
first opening (blastopore) becomes anus and mesoderm and coelom forms from outgrows of primitive gut
What are the 4 key parts of the body plan of Cnidaria?
1) epidermis (ectoderm)
2) gastrodermis (endoderm)
3) mesoglea (collagen and proteoglycans)
4) gastrovascular cavity (archenteron)
What are the two types of ways that the body of Cnidaria can be oriented?
1) Polyp (sessile - does not move) (shapes like a P, facing up)
2) Medusa (motile) (shaped down like an M)
(most life cycles include both)
How do Cnidaria obtain energy?
- Carnivorous - inject prey w/ toxins and capture prey
- extracellular digestion in gastrovascular cavity
What are the 4 different diverse types of Cnidaria?
1) Hydrozoa (fresh water, no medusa stage, moves by gliding/floating)
2) Scyphozoa (true jellyfish)
3) Cubozoa (box jellyfish)
4) Anthozoa (“flower animals”, retract tentacles in defence)
What are some of the causes of coral bleaching?
it is a stress response to increase water temp, increase UV radiation, pollution, and disease (bacteria).
What are the three types of body cavities for Cnidaria?
1) Coelomate (mesoderm lines entire cavity as a “peritoneum”)
2) Pseudocoelomate (mesoderm lines outside of pseudocoel)
3) Acoelomate (no body cavity, solid except for digestive space)
What are two ways to make coelom?
1) Schizocoely (splitting within mesoderm - protostomes)
2) Enterocoely (mesoderm forms pockets from gut - deuterostomes)
What are the sensory structures of Platyhelminthes “flat worms”?
1) Mechanoreceptors (touch)
2) Chemoreceptors (taste/smell)
3) Photoreceptors (light)
Describe the nervous system of a flatworm?
Very simple, long nerve cords, two cerebral ganglia, concentration of neurons which acts as the “brain”
Describe what a Turbellaria is?
It is free living, a type of a flatworm, regenerates a new body, anterior end will always develop into head, reproduce asexually by fission and sexually
Describe what a Trematoda and Cestoda is?
Both are endoparasitic (live on inside of host) and have a flat body with suckers.
Describe what a Cestoda is
Ectoparasitic (lives on outside of host), lives in intestines of vertebrate, no mouth or digestive system, scolex which are suckers/hooks, proglottids which is their reproductive system.
Define Lophotrochozoa
Diverse group of phyla with similar ribosomal/RNA sequences
Define Trochophore larva
Type of larva common to marine mollusk and other phyla forms of Lophotrochozoa
Define Nephridia
Invertebrate organ, occurs in pairs and performs similar to vertebrate kidney, removes metabolic waste.
Give a few characteristics about Annelida
“segmented worms”
moist environments
Lophotrochozoa (annelids and molluks)
What are some advantages for segmentation?
1) multiple copies of organs and structures
2) efficient nervous control, ganglion in each segment, faster responses, efficient local movement
3) increase in body size
4) regeneration
What are the different systems in annelids and a bit about each one? (5 systems)
1) Nervous system (anterior brain, segmented ganglia, ventral nerve cord)
2) Respiratory (skin or gills)
3) Excretory (tubular nephridia)
4) Digestive system (complete)
5) Circulatory system (closed, dorsal and ventral blood vessels, aortic arches=hearts)
Annelids: Advantages of a closed circulatory system?
- improved exchange between deeper tissues and surface (02,C02)
- faster transport of nutrients and gases
- permits development of thicker body
What are three types of annelids?
1) Polychactea - bristle worms, mainly marine, filter-feeders
2) Oligochaeta - terrestrial and aquatic, no parapodia, citellum (secretes cocoon for embryo development)
3) Hirudinea (freshwater, ectoparasitic, carnivorous, medicinal uses)
Mollusks
- 2nd largest animal group after anthropoids
- terrestrial or aquatic
- very diverse
- bilateral symmetry, triploblastic
- gills if aquatic, lungs if terrestrial
Polyplacophora
Poly= many
8 overlapping plates, segmented
grazing, herbivores
external fertilization, separate sexes
Bivalvia
Bi=two two valves hinged shell reduction of head, enlargement of foot and gills not very motile siphons modify the mantle cavity either dioecious or hermaphroditic
What is a siphon?
Extensions of posterior mantle, water flows in the cavity and across gills that act as filter for food
Dioecious vs Hermaphroditic
Dioecious (one set of female or male organs)
Hermaphroditic (have both sets)
Gastripoda
- snails or slugs
- herbivores, predators, scavengers
- complex head and eyes
- internal or external fertilization
- either dioecious or hermaphroditic
Cephalopoda
- great vision
- complex behaviour - visual communication w/ colour, texture
- arms with suckers/hooks
Why are mollusks economically & culturally important?
- food (jellyfish)
- jewelry (pearls)
- exotic invasions
- vectors for parasites
Define Ecdysozoans
Group of prostome animals, defined using 18’s ribosomal RNA genes
Define Hemocoel
Body cavity that contains blood or hemolymph, functions as part of circulatory system
Cryptobiosis
Physiological state - metabolic activity is reduced to undetectable levels w/o disappearing known to animal and plant groups that adapt to survive long periods of very dry conditions
Define Ecdysozoa
- A big subgroup of arthropods (insects, spiders, crustacean)
“ slip out/escape”
Define Nematoda
- part of Ecdysozoa group
- round worms
- body protected by elastic cuticle
- feed on bacteria, fungi, parasites
Define Tardigrada
- water bears
- part of Ecdysozoa
- segmented, short legs
- moist areas
- suspending metabolism
- feed by sucking fluids form plants and animals
Define Onychophora
- type of Ecdysozoa
- claw bearing, velvet worms
- segmented
- humid environments
- champion spitters of animal kingdom
Define Arthropoda
- part of Ecdysozoa group
- segmented animals w/ jointed appendages, hemocoel, exoskeleton
- uses specific mouth parts to eat
- most diverse group
What are the 4 main characteristics of Arthropods?
1) segmented body plan
- specialized segments
- vary from less than 20 to over 100
2) jointed appendages
- specialized functions
- either biramous (branched) or uniramous (unbranched)
3) Developed sense organs
- highly cephalized
- elaborate sensory organs (eyes, hair, ect)
4) Rigid skeleton
- non-living
- covers all external surfaces, digestive tract, trachea
- multilayers
- chitin, protein + CaC03
Advantages and disadvantages of Rigid Skeleton (arthropods)
Advantages: support, muscle attachment, protection, allow faster movement, opportunity to change morphology, location of pigments
Disadvantages: inflexible + heavy, must be periodically shed which requires energy, in most cases cannot respiration through skin, need spiracles (pores) and trachea (tubes)
Metamorphis
- Sheding (moulting) which changes morphology
- each larva (instar) produces a new exoskeleton
- at the shed time, modification is possible
- insects do not shed as adults but crustaceans do
The process of a complete metamorphosis
- there are four stages
Eggs -> larvae -> Pupa -> Adult - butterflies, moths, bees, ants, ect
- there is a resting stage
Incomplete metamorphosis
- no “resting” stage
- grasshopper, crickets, mites ect.
- Eggs -> Nymphs -> adults
What are the two hormones involved in metamorphosis? Explain.
- hormones regulate moulting, chemical messengers which are secreted by endocrine cells, distributed by blood, bind to target cell receptors
1) PTTH, produced and stored by brain, production influenced by environmental cues, controls activity of prothoracic gland
IT TRIGGERS
2) Ecdysone, produced by prothoracic gland, target cells= epidermis, response = ecdysis
THIS THEN TRIGGERS MOULTING
Define Phenotypic plasticity
The ability of one genotype to produce more than one phenotype when exposed to different environments
Define Parthenogenesis
Form of asexual reproduction in which embryo develops without fertilization by sperm
What are the 4 major groups of arthropods?
1) Myriapods (millipedes)
2) Chelicerates (spiders)
3) Crustaceans (shrimps)
4) Insects (flies)
Are animals and arthropods monophyletic or paraphyletic?
Monophyletic
Are crustaceans monophyletic or paraphyletic?
Paraphyletic
Arthropod Respiratory Systems
1) Insects and most myriapods: tubular trachea w/ holes, carry 02 to blood gills
2) crustaceans: gills
3) chelicerates: some trachea and spiracles, book gills or book lungs
Arthropods: Circulatory system
- open system (hemolymph fills body cavity)
- dorsal tubular heart w/ pores, drives hemolymph into hemocoel spaces
- one- way valves
Arthropods: sexual reproduction
- most are dioecious
- lay eggs/ care for their young
Myriapods
- group of arthropods
- head and body (segmented)
- centipedes = carnivores (poison fangs)
- Millipedes = detrivores, herbivores
Chelicerates
- group of arthropods
- cephalothorax - appendages
- abdomen - no appendages
- no jaw, sexes separated
- # 1 fangs, #2 pincers, #3,4,5,6 legs (4 pairs)
Crustaceans
- mainly marine but also land
- “zooplankton”
- head, thorax, abdomen
- appendages off each segment
- separate sexes
Insects
- 3 body regions
- separate sexes
- external mouthparts
- important for ecosystem services (pollination, food source, decomposers, ect)
