Midterm Flashcards
1
Q
Taxonomy
A
- naming and categorizing organisms
- Based on shared traits
i. Morphological traits – physical appearances - Used first – didn’t always have other technology
- Not the most accurate
ii. Developmental features/processes
iii. Molecular (e.g. gene/protein sequences) - Carolus Linnaeus (1707-78)
a. Developed the Binomial scientific naming system Genus species
i. Latin names for consistency
ii. E.g.: Homo sapiens; Vulpes vulpes
b. Developed a formal hierarchical system of taxonomy – dear king Philip came over for good soup
i. species – smallest (names are italicized)
ii. genus (names are italicized)
iii. family
iv. order
v. class
vi. phylum
vii. kingdom
viii. domain – largest - Taxon (plural: taxa) – general term for any of the taxonomic units; e.g. the family taxon is comprised of multiple genera (plural of genus).
2
Q
Homology vs analogy
A
- Homology – similar morphology and DNA due to shared ancestry
a. Homologous structures can be
i. Similar structure (not always obvious) - Ex. a limb – all have humerus, carpals, metacarpals (etc..)
ii. Same or different function - Ex. arm, bat wig, cat leg, whale fin
iii. Derived from common ancestor - Ex. human, cat, whale, bat – all derived from common ancestor
- Analogy – similarity due to convergent evolution
a. Similar traits developed independently in order to overcome some sort of obstacle in distantly related species
i. Ex. birds and moths – analogous structures
b. Analogous structures can be
i. Different structure (when you look closely)
ii. Similar function
iii. Due to convergent evolution
3
Q
Phylogeny
A
- Phylogeny – the evolutionary history of a species or group of related species; ancestry
- Phylogenetic tree – grouped based on similarities
a. Closer together on tree = more similar
b. Structure
i. Nodes – branch point; speciation event - Speciation event – divergence of 2 species; a change in the DNA of an organisms to make it different enough to survive and become a new species
- Tree branches can be rotated around a branch point
ii. Polytomy – a branch from which more than 2 groups emergy - Unresolved level of divergence among them
iii. Common ancestor – just before node; represented by branch point - Sister taxa – groups that share an immediate common ancestor
iv. Rooted tree – includes a branch to represent the last common ancestor of all taxa in the tree - Ancestral root
v. Outgroup – a more distantly related group of organisms that serves as a reference; similar enough to others in taxa but different - Phylogenies use
a. Morphologies (ex. fossil records)
b. Genetic sequences
c. Biochemistry of living organisms - Must show similarities due to homology, not analogy
a. Homology – organisms with similar morphologies or DNA sequences are likely to be more closely related than organisms with different structures or sequences
i. Homologies – phenotypic and genetic similarities due to shared ancestry
4
Q
Systematists
A
- Systematists – classifies organisms and determines their evolutionary relationships; depicted as branching phylogenetic trees
- Used to infer evolutionary relationships:
a. Fossils
i. Ex. Archaeopteryx fossil – showing similarities between birds and Saurischian dinosaurs
b. Morphological data – doesn’t show homogenous DNA level
c. Biochemical data – more accurate; usually proteins
i. Ex. myoglobin proteins conserved in AA sequence and structure
d. Genetic data – more accurate; sequences diverge as species become more evolutionarily distant
i. E,x. DNA sequences – red differs
1. Human: atg gcc ctg tgg atg cgc ctc ccc ctg ctg gcg ctg gcg ctg
2. Chimp: atg gcc ctg tgg atg cgc ctc ccc ctg ctg gcg ctg gcg ctg
a. More similar to humans
3. Gorilla: atg gcc ctg tgg atg cgc ctc ccc ctg ctg gtg ctg gcg ctg
4. Dog: atg gcc ctc tgg atg cga ctc ccc ctg ctg gcc ctg gct ctg
a. The most distantly releated to humans
5
Q
Research tools used to infer relationships
A
- DNA sequencing platforms
a. Researchers can now easily sequence specific genes from organisms to compare genes – cost is going down and many programs are available
i. Nanopore sequencer – oxford biotech; can sequence an entire genome in 24 hours; the size of a USB stick
b. Make sequences available to scientific community to test hypothesis - Genome sequencing projects – determining the sequence of all the DNA in an organism
- Computer programs and mathematical tools are used when analyzing comparable DNA segments from different organisms
a. Computer algorithms are used to score these changes – compare scores among species to find closest similarities
6
Q
Cladistics
A
- Cladistics – groups organisms in phylogeny by common descent; groups of related species
- Clade – a group of species that includes an ancestral species and all its descendants
a. Not always 100% clear - Classifications
a. Monophyletic clade – consists of the ancestor species and all its descendants
i. “true clade”
b. Polyphyletic clade – grouping includes distantly related species; does not include their most recent common ancestor
i. Old school phylogeny – constructed before we had all the information
ii. Ex. cetaceans (dolphins) and seals – look similar but do not share the same most recent common ancestor
c. Paraphyletic clade – grouping consists of an ancestral species and some, but not all, of the descendants
i. Old school phylogeny
ii. Ex. excluding cetaceans – didn’t initially see similarities between dolphins and hippos - Phylogenies are getting revised constantly as more information is acquired
7
Q
Shared ancestral vs shared derived
A
• Shared ancestral character – a character that originated in an ancestor
o Ex. vertebrate system of chordates – can be traced to all descendants
• Shared derived character – a character novel to a particular clade (not found in the ancestor)
o Ex. hair – not found on all descendants or in common ancestor
o Ancestor can be considered an outgroup if it lacks a character shared by all it’s descendants
• A character can be both ancestral and derived, depending on the context
8
Q
Genome
A
- Genome is used to compare nucleic acids or other molecules to infer relatedness and determine evolutionary history
a. DNA coding for rRNA changes relatively slowly – useful for investigating branching points hundreds of millions of years ago
b. mtDNA (mitochondrial DNA) evolves more rapidly – can be used to explore recent evolutionary events - DNA Barcoding Project – can identify many species
a. Used against poachers (can detect type of animal from blood, hair, or meat
b. Used to detect which animal attacked human - rRNA and mtDNA are useful because
a. Easy to isolate these genes from material, even when tissue is old
b. Many copies of rRNA genes/genome
c. Many mitochondria/cell, each with mt chromosomes
9
Q
Eukarya supergroups
A
- Excavata – unicellular euks in aquatic environment
a. Diplomonads
b. Parabasalids
c. Euglenozoans - SAR
a. Stramenopile
i. Diatoms
ii. Golden algae
iii. Brown algae
b. Alveolate
i. Dinoflagellates
ii. Apicomplexans
iii. Ciliates
c. Rhyzaria
i. Forams
ii. Cercozoans
iii. Radiolardians - Archaeplastida
a. Red algae
b. Green algae
i. Chlorophytes
ii. Charophytes
c. Land plants - Unikonta – many groups
a. Amoebozoans
i. Slime moulds
ii. Tubulinids
iii. Entamoebas
b. Opisthokonts
i. Nucleariids
ii. Fungi
iii. Choanoflagellates
iv. Animals
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10
Q
The unikonta - 2 major clades
A
Two major clades
- Amoebozoans – slime molds, Amoeba sp, etc…
i. Amoebas – no symmetry; able to pump water to move through environment
b. Lobular pseudopodia – false limb - Opisthokonts – animals, fungi, and closely related protists groups (Choanoflagellates)
a. Animals – more closely related to fungi, slime molds, and amoebas, than plants
b. Fungi are very large – they form networks underground
c. Choanoflagellates – an outgroup for the animals
i. Similar morphology to sponges - Lots of diversity – not as much as other taxa
11
Q
Animals
- diversity
- typical characteristics
- diplontic life cycle
- evolution of multicellularity
A
- 1.8 known species – animals make up the majority
a. Majority are invertebrates (1.25 million)
i. Not as much diversity in vertebrates (58,000)
b. Over 280,000 known plant species - Typical characteristics
a. Multicellular – specialized biological processes that occur in different tissues
i. Interconnected cells - Gap junctions – communication
- Tight junctions – hold/interconnect cells together
b. No cell walls
i. Unlike plants and bacteria – cellulose is primary component
c. Directional mobility – will have at some point in their life
i. Importance – food, shelter, reproduction, escape predators, migration
d. Heterotrophic – obtain energy by consuming energy producers or other heterotrophs
e. Specified embryonic tissue
i. Ectoderm – epidermis
ii. Mesoderm – muscle and skeletal structure
iii. Endoderm – mouth, digestive system, respiratory system, anus - Diplontic life cycle
a. Development
i. Gametes – haploid - Egg and sperm – fuse to form diploid zygote
a. Fusion of zygote – this is when we start to see evolution and mutations occur
ii. Zygote – diploid - Somatic cells
b. Ex. Xenopus frog – model system
i. Egg and sperm fuse – form diploid zygote
ii. Cleavage/mitosis occurs
iii. Early embryo late embryo
iv. Differentiates into tadpole
v. Metamorphosis – changes completely from requiring aquatic to being able to live terrestrially or aquatic enviro - Evolution of multicellularity
a. Choanoflagellates – common ancestor is shared with animals
i. Outgroup of animal clade – closely related but are unicellular
ii. Live in colonies – they look multicellular but are not
iii. Unicellular – anatomy - Body
- Collar – fingerlike projections
a. Made of microtubules
b. Used for movement - Flagella
iv. 3 lines of evidence that they’re closely related to animals - Cell morphology
a. Similar cell to porifera - Cell morphology unique to animal cells
a. No cell wall, no plastids - DNA sequence homology
b. Metazoa clade – multicellular organisms; synonymous with animalia clade
12
Q
Grade vs clade
A
Clades – share a common ancestry
o Monophyletic clades – ancestor and all descendants
o Implies relationships – divergent evolution
Grades – share key biological feature only; usually come up through evolution to overcome obstacle
o No relationship between organisms
o Convergent evolution – unrelated groups finding similar solution to solving different problems
Eg. Coelom (body cavity), segmentation
13
Q
10 major animal phylum - know the characteristics of each
- porifera
- cnidarians
- chordata
- ectodermata
- playhelmenths
- brachiopoda
- annelida
- mollusca
- nematoda
- arthropoda
A
- Porifera – sponges
a. Basal group – evolved early in the tree of life; earliest descent of animals
i. Doesn’t have all the properties of others (ex. true tissues) - Could be considered an outgroup – depends on comparisons
ii. Have cells that look almost identical to single celled choanoflagellate – only determined through DNA sequencing that they are not actually closely related
b. Simple body structure – no symmetry
i. Lack true tissues – no membranous layer separating
ii. Two cell layers - Epidermis (peach) – outer covering
- Choanoderm (blue) – named because they look like choanoflagellate
a. Draws in food particles
b. Passed through amoebocytes
iii. Middle region – water movement is used to stay upright - Porocytes (purple) – allows for movement of water
a. Spongocoel – central water filled area; water moves through - Mesohyl
a. Amoebocytes (cyan) – look like amobaes
b. Hardened spicules (yellow) – provide structure
iv. Pulls water current in and pushes out to stay upright – dye experiment
c. Random growth – cells are totipotent
i. Totipotent – can regenerate and change cells fate - Also found in plants
ii. Broken apart sponge/a single cell – can develop into a new organism - All sponge cells can give rise to any of the other cell types
iii. Can self assemble with other cells into a sponge – separated sponge will spontaneously reassemble - Cnidaria – jellies, anemones, corals
a. Evolution of radial symmetry – likely evolved from cnidaria
i. No right or left side – several planes of symmetry
ii. Only one body axis - Top – oral
a. First development of mouth - Bottom – aboral
a. Anchored to substrate
iii. Diploblastic – first formation of eumetazoan tissues (2 embryonic cell types) - Epidermis
- Gastrodermis
- Mesoglea – non cellular jelly layer
b. 2 body shapes
i. Polyp – crawling animals; anemones and hydras - Cylindrical
- Mouth faces up – acts as mouth and anus
a. Connected to aboral by stalk/body - Aboral side moves animal
ii. Medusa – free swimming jellies - Mouth down – acts as mouth and anus
- Tentacles point down
a. Move water to get food
b. Can also be protective
c. Clades
i. Anthozoa – polyp - Anemones and corals
ii. Medusozoa – medusa - Jellies and hydrozoans
a. There are freshwater jellies – outbreak in Manitoba along Ontario border
b. Hydrozoans – have more calcium and are able to stand up straight - Some have proteins that glow in the dark – scientists use to understand function of genes and proteins associated with animals
- Chordata
a. Bilaterian
i. Deuterostomia – mouth second
b. 4 characteristics
i. Notochord – provides strength & support; usually cartilage - Runs the entire length of organism
ii. Dorsal hollow nerve chord – develops into CNS and spinal cord
iii. Pharyngeal arches – allows movement of water/oxygen/particulates - Pharynx = throat
- Opening – mouth or water through gills
a. Allows movement of water
b. Suspension feeding devices
iv. Post anal tail – can diminish or become reduced during embryonic development - Contains skeletal elements and muscles
c. 3 major clades
i.
ii. Cephalochordates – aquatic - Lancelets – most basal group of living chordates
a. Maintain chordate characteristics throughout lifespan
b. Microbes – burrow into sand
iii. Urochordata – aquatic - Tunicates
a. Chordate characteristics are present only in larvae stage – free swimming
i. Metamorphosis – loses many dorsal hollow nerve cord, post anal tail, notochord
b. Maintain pharyngeal slits as adults – allows movement of water & collects particulate
c. Excurrent siphon – water enters & collects food with cilia
iv. Vertebrata – aquatic & terrestrial - Skeletal and nervous system – increased efficiency at
a. Capturing food
b. Evading predators - Derived characters (not from ancestor)
a. Vertebrae enclosing spinal cord – repeated segmentation
b. Elaborate skull
c. Fin rays (aquatic species) - Evolution
a. Jawless fish – basal species
i. Hagfish - Bottom dwelling scavengers
- Skull made of cartilage
- Retains notochord as adults
- Produces slime as a defense mechanism
ii. Lampreys – freshwater and oceanic - Most are parasites
- Have teeth – clamp round jawless mouth on live fish
- Skeleton made of cartilage
b. Jaws – formed from fused skeletal support of pharyngeal slits
i. Able to capture prey
ii. Evolved in Gnathostoma clade - Sharks
- Ray finned fish
- Lobe finned fish
- Amphibians
- Reptiles & birds
- Mammals
c. Lungs & bone
i. Evolved in Osteichyan clade – aquatic enviro - Ray finned fish (boney fish)
a. Flexible rays modified for maneuvering & defense
b. Trout, salmon, cod - Lobe finned fish (muscle on their fins)
a. Lungfish
b. Tetrapods
d. Limbs
i. Evolved in tetrapods – gnathostomes - Fins of lobe fin – become limbs
- Head is separated by body with neck
- Bones of pelvis are fused to backbone
- Adult tetrapods do not have gills – larvae may be aquatic
ii. Amphibians – tetrapods - Salamanders – some are only aquatic, some are terrestrial
a. Often retain juvenile characteristics as adults
b. Fertilization is external - Frogs – mostly terrestrial
a. Larvae are aquatic – gills
b. Variety of adaptation of avoid predation
e. Amnion
i. Evolved in clade amniota - Reptiles & some mammals
a. Derived character – not ancestral - Amniotic egg with 4 extraembryonic membranes
a. Amnion – shock absorber
b. Chorion – gas exchanger
c. Yolk sac – provides nutrients
d. Allantois – waste storage - Advantage – able to protect young on terrestrial environment; allows eggs to be laid on land; no longer require water
f. Milk & hair
i. Evolved with mammalia - Mothers nourish young with milk
- Hair helps to retain heat
ii. 3 clades - Monotremata – lays eggs
a. Ex. platapus - Marsupials – short gestation; babies are underdeveloped
a. Ex. kangaroo & koala - Eutherials – longer gestation & better development
a. Ex. humans & elephants - Echinodermata – ex. sea stars, sea urchins, sand dollar, sea cucumbers
a. Structures
i. Complete gut – separate mouth and anus (they are close together)
ii. Tube feet – locomotion and sensing
iii. Hydraulic canals – the water vascular system - Water pressure enables movement – thousands of tiny feet suck up water through movement of ampulla (turkey baster)
b. Larvae have bilateral symmetry (doesn’t have to be in adulthood)
c. Most adults have radial symmetry – multiples of 5
i. Pentaradial – central disc & 5 arms - sea stars and sea urchins
ii. Predators – they crawl on sea floor; eat snails, sand dollars
d. Red brittle star – Ophiocoma wendtii
i. Have photoreceptors – light sensing cells; can see without eyes - Evolutionary advantage – can sense light and shadows
ii. Found in Caribbean and Gulf of Mexico
e. Characteristics
i. Sea stars and brittle stars – can regenerate limbs as long as central disc remains intact
ii. Most have hard coverings - Sea urchins – spiny
- Sea cucumbers – soft
a. They still have spines & homologous gene sequencing – still echinoderms
iii. Doesn’t have true cephalization – they only have a central disc - Platyhelminthes – flatworms
a. Part of Lophotrochozoa clade – widest range of animal body forms
i. Classified by a few characteristics - Lophophore – feeding structure
a. Generates current – captures plankton & bacteria - Trochophore – common larval form (not all have)
a. Little cilia allow movement - Bilaterian – coelom (body cavity) and digestive tract have 2 openings (complete gut)
a. Lots of variability – clams, slugs, snails, octopus - Triploblastic
- Often aquatic or live in damp environments
ii. Often develop as protostomes – cleavage is spiral and determinate
iii. Includes – flatworms, rotifers, brachiopods, molluscs, annelids
b. Characteristics
i. Rudimentary cephalization – light sensitive areas
ii. Incomplete gut – evolutionary loss; they have a gastrovascular cavity - Do not have distinct mouth/anus
iii. Marine, freshwater, and terrestrial (damp) - Free living and parasitic
iv. Acoelomate – no body cavity
v. Flat body - Gas exchange occurs through skin
- Easier to hide from predators
vi. Not segmented
c. 3 major groups
i. Turbellarian
ii. Trematoda - Clade neodermata – parasitic trematodes (flukes); can live on or inside hosts
a. Schistosoma – causes swimmers itch
b. Cestodes – tapeworms that live in intestine
i. Loss of gastrovascular cavity over evolution
ii. Can reach 20m in length
iii. Used to be prescribed to lose weight
iii. Cestoda - Brachiopoda
a. Part of lophotrochozoa
i. Has lophophore – used to capture food
ii. No trochophore larvae
b. Attached to sea floor – cilia allows movements & capturing of food
c. Lamp shells
i. 2 halves of the shell are dorsal & ventral instead of lateral – right and left are symmetric - Top and bottom shell are not identical – defining characteristic of brachiopods
ii. 2 muscles – one opens & one closes
d. Clade inarticulate – small or no hinge
i. Ex. lingula
ii. Very large pedicle – helps to anchor them and burrow down into sand
a.
iii. Complete gut – mouth, intestinal tract, anus
a.
e. Clade articulata – large hinge
i. Incomplete gut - No place for waste to escape – come into mouth , processed, leaves through mouth (no anus)
- Intestines protrude out of the back of the shell
- Annelida
a. Part of lophotrochozoa
i. Trochophore larval stage – undergo metamorphosis; little cilia allow movement as larvae
ii. Locophore – mouth structure
b. Segmented worms – allows greater mobility
i. Segmentation – grade of organization (developed independently)
ii. Organs are compartmentalized
c. Live in water & damp soil – they emerge after heavy rain due to a lack of oxygen in the soil
d. Errantia clade – actively mobile, segmented worms
i. Mostly marine
ii. Predators, grazers, scavengers
iii. Appendages - Parapodia and palps – locomotion; antennae whiskers used for sensation
e. Sedentaria clad – less active segmented worms (tubeworms, earthworms, leeches)
i. Marine sediment and soil
ii. May have elaborate gills if living in tubes - Tube worms – extend their gills
iii. Leeches – parasitic; feed off other invertebrates
iv. Earthworms – can extract nutrients from soil - Mollusca
a. Part of lophotrochozoa
b. Common structures
i. Muscular foot – movement, prey capture, digging
ii. Mantle cavity – water filled chamber (aquatic) - Contain gills, anus (posterior), excretory pores
- Secretory structures – often leave slime trails
- Produces the shells – protects organs that form the visceral mass
iii. Radula – functions like a tongue to capture food - Aggressive – can eat away at plants, algae, shells of other orgs
- Anterior end
iv. Visceral mass – houses internal organs (heart, DI tract, stomach) - Pushed inward due to large muscular foot
a.
c. Molluscan clades – 4 major
i. Gastropods – snails & slugs - One piece shell – can hide in
- Radula at head – used to feed off plants & algae & burrow into other orgs shells
- Ex. blue sea dragon – tiny blue shell-less gastropod mollusc
a. Glaucus atlanticus
b. Found in warm environments
c. Feed on venomous animals (ex. hydrozoan Portuguese man o’ war) – integrates poisons & stores stinging nematocysts from cnidarians within its tissues (defense mechanism)
ii. Bivalve – clams, oysters - 2 piece shells – hinged or non
- No distinct head
- Sedentary lives – often attached to substrate
- Suspension feeders
- Eye like structures – can sense environment
iii. Polyplacophora – chitons - Many piece shell – segmentation allows flexibility
- Scrapes algae off rocks
iv. Cephalopoda – squids, octopus, cuttlefish - Highly intelligent – cephalization allows integration of complex info
a. Studied to understand complex behaviour - Camouflage
- Tentacles capture prey
- Nematoda – roundworms
a. Part of clade Ecdysozoa
i. Characterized by tough cuticle or shell – exoskeleton - Requires periodic molting and stepwise growth – doesn’t grow with animal
- Provides protection
- Made of chitin
b. Roundworms – most common animal on earth; can live aquatic or terrestrially
i. Characteristics - Pseudocoelomate body structure – mesoderm does not cover the endoderm
- Body is covered by cuticle – must periodically shed to grow
- Flexible body
- Free living and parasitic – plant and animal hosts
a. Play a large role in agriculture
ii. Ex. Caenorhabditis Elegans – type of roundworm - A model system – used for research (often genetics and biochem)
a. Small size
b. Easy to grow in lab
c. Sequenced genome
d. Simple body form
e. Lots known – lots of peer reviewed material - One of the first species used in turn of the century studies (early 2000s)
- Arthropoda
a. Part of clade Ecdysozoa
i. Characterized by tough cuticle or shell – exoskeleton - Requires periodic molting and stepwise growth – doesn’t grow with animal
- Provides protection
- Made of chitin
b. Very diverse – 2/3 known species are arthropods
i. Members are fond in nearly all habitats in biosphere – lots of evolutionarily beneficial characteristics
c. Body plan
i. Segmented body – derived; assists in motility
ii. Exoskeleton
iii. Jointed appendages – important due to exoskeleton - Evolved in Arthropoda
- Used for
a. Walking – joints on leg
b. Defense – claws for defense and intimidation
c. Fangs – inject venom; appendage of head; can paralyze larger organisms
d. Sensation – antenna used to interrupt surroundings; cephalization
d. General characteristics
i. Segmented – derived
ii. Body is covered in cuticle – proteins & chitin - Must molt to grow
iii. Tagmata – segments grouped together - Head
- Thorax (middle)
- Abdomen
iv. Open circulatory system – hemolymph (instead of blood) is circulated into the spaces surrounding tissues and organs
e. 5 major clades in phylum
i. Hexapoda clade – insects - Evolution of flight – occurred in Hexapoda clade
a. Insect wings – extensions of the exoskeleton & cuticle (brittle)
i. Not appendages
ii. Contributed to evolutionary success – escape predators, food sources, disperse to new habitats quickly - Includes insects & 6 legged kin – huge clade; live in almost every terrestrial and freshwater habitat
a. Insects – always have 3 body parts & 6 legs
i. Usually have 4 wings & 2 antennae - Undergo metamorphosis – 2 types
a. Complete – larvae (maggot/caterpillar) to adults (wings)
i. Pupa – hard covering; protects during transformation
b. Incomplete – younger nymphs resemble adults (true bugs)
i. Emerge from eggs very young - Characteristics
a. Exoskeleton – lightweight & chitinous
b. 3 tagmata – have compartments within
i. Head – 5 segments - Not cephalothorax – occurs mainly in spiders and chelicerates
ii. Thorax – 3 segments
iii. Abdomen – up to 11 segments - Clades within hexapoda
a. Complete metamorphosis – 4 groups winged insects
i. Include beetles, flies, wasps & bees, moths
b. Incomplete metamorphosis – 2 groups winged insects
i. Include leaf hopper, aphids, grasshoppers
ii. True bugs
ii. Remipedians (crustacean) – ex. silverfish - Paraphyletic – does not include all descendants of ancestor (insects); does not include all crustaceans
a. Terrestrial insects are more closely related to crustaceans that myriapods
b. Some crustaceans are more closely related to insects than other crustaceans - Often terrestrial??**
iii. Other crustaceans - Paraphyletic – doesn’t include all crustaceans
- 2 tagmata
a. Cephalothorax
i. Several pairs of antennae
ii. Chelipeds
iii. Walking legs – won’t all have the same number
b. Abdomen/tail – heavily muscled - Types
a. Isopods – pill bugs; like damp and dark
b. Decapods – crabs, lobster, crayfish, shrimp
i. 10 legs (“deca”)
c. Copepods – sea monkeys, sea lice
i. Critical for maintaining aquatic environment
d. Barnacles
i. Usually attached to substrate via pedicle – shallower water
ii. Feet protrude out – bring food in
iii.
iv. Myriapods - Centipedes – poisonous & carnivorous
a. One pair of legs per segment - Millipedes – herbivorous
a. 2 pairs of legs per segment
v. Chelicerates - Eurypterids – horseshoe crabs (used to study physio of animals), sea spiders
- Arachnids – spiders, scorpions, ticks (becoming a big issue), mites
a. 2 tagmata
i. Cephalothorax - Cephalothorax
a. Pedipalp – poisonous
b. Chelicera - ??** - Abdomen – houses organs
a. Posterior abdomen – heart, reproductive structures, digestive system, silk glands
b. 6 pairs of appendages
i. Chelicerae – 1 pair
ii. Pedipalp – 1 pair; poisonous
iii. Walking legs – 4 pairs
c. No antennae – have sensitive eyes
d. Open circulatory system – hemolymph leaves heart in arterioles; no veins to bring blood back to the heart
14
Q
Evolution of true tissues
A
- Tissues – groups of specialized cells
a. 2 groups based on presence of membranes
i. Parazoa – cell are not separated by membranes - Sponges – lack tissues and radial symmetry; no true tissues
ii. Eumetazoa – cells are separated by membranes - Eumetazoan tissues
a. Development
i. Egg and sperm come together and form zygote
ii. Two major events early in development - Cleavage
a. Mitotic divisions – asexual reproduction
b. 8 cell stage – continue to divide to blastula
c. Blastula – hollow ball of cells - Gastrulation – invagination and formation of cavity in blastula
a. Forms – primitive gut and blastophore (mouth)
b. Diploblastic – 2 germ layers in embryo
i. Ectoderm – outer layer of embryo
ii. Endoderm – inner layer of embryo - Develops via gastrulation
- Lines digestive tract, liver, lungs
- Triploblastic evolution – 3 germ layers in embryo
a. Mesoderm – forms inner muscles and organs
i. Fills space between ectoderm and endoderm
b. Eg. Flatworms, arthropods, vertebrates
15
Q
Body cavities
A
Three grades of organization – occurred multiple times in different phyla to overcome obstacle
- Only in triploblastic animals – 3 germ layers
• The way they’re organized is a defining feature
- (eu)Coelomates – cavity is completely lined with mesoderm; mesoderm lines endo and exoderm
a. Closed circulatory systems
b. Coelom – body cavity
i. Coelomates – an organism that has a true body cavity
c. Ex. Earthworms (annelids), chordates, echinoderms, molluscs, arthropods - Pseudocoelomates – body cavity partially lined by tissue derived from mesoderm
a. Protostomes
b. Partial
i. Ectoderm is in contact with mesoderm
ii. Mesoderm does not line DI tract/endoderm – hence pseudo
c. Ex. Roundworms (nematodes) - Acoelomates – no body cavity; some animals have cavities that are not completely formed
a. No space between tissue layers
b. Ex. Flatworms (platyhelminths)
16
Q
Evolution of bilateral symmetry
A
- Derived character – not ancestral; evolved in phyla independently
a. Occurs at some stage in their life – doesn’t have to be adulthood - Structure
a. Dorsal (top) and ventral (bottom) side
b. Right and left side
c. Anterior (front) and posterior (back) - Often exhibit cephalization – sensory systems concentrated in anterior end (head)
a. Cephal – formation of a head
b. Central nervous system formation
i. Clustered neurons – brain and ganglia
ii. Used for – active movement, complex integration and complex behaviour
c. Radially symmetric lack it – networks of individual neurons
i. Often sissile (immobile) or weakly swimming (drifting)
17
Q
Evolution of complete gut
A
2 openings
- Derived character – not ancestral; evolved in phyla independently
- Require 3 tissue systems
a. Differs from gastrovascular cavity in cnidarians – single opening; ancestral character - Two possibilities during gastrulation
a. Protostomia clade – blastopore becomes mouth (proto = first; stome = mouth)
i. Anus may form later
ii. Cleavage division – spiral and determinate - Cell fate is established early
- Cell divisions are not at right angles to each other – they spiral
iii. Ex. snails
b. Deuterostomia clade – blastopore becomes the anus (deuteron = second)
i. Mouth forms later
ii. Cleavage division – radial and indeterminate - Cell divisions are at right angles to each other – zygote divides into right and left halves
- Each cell in early stage of embryo (up until embryogenesis) has the capacity to develop into complete embryo – allows maternal twins development and is a source of embryonic stem cells
iii. Ex. chordates, echinoderms
18
Q
Evolution of segmentation
A
segmentation – identical repeating body units
Convergent evolution – found multiple times in bilaterians; unrelated or distantly related organisms evolving in similar body forms
• Present in 3/10 major animal phyla – Arthropoda, Annelida, Chordata (invertebrates)
• Derived character
Different genes are responsible for each segment
19
Q
animal forms are limited by
A
o Strength – you need proper skeleton to support structure
o Diffusion – there are some that only get gas through diffusion of skin
More complex animals – cannot use diffusion across skin for oxygen supply
o Heat exchange
Birdmans rule – animals further north will have better body sizes that allow for heat retention
o Movement
Ex. swimming – convergent evolution in seals, penguins, tuna
20
Q
4 adult tissue types
A
- Epithelial tissue – outer coverings and tube linings
a. Many functions – outer coverings and inner linings (derived from ectoderm & endoderm)
i. Protection – keep substances out; larger scale
ii. Physical barrier – keep substances out; smaller scale (think selective permeability of cells)
iii. Controlling the movement of substances – ex. food absorption in DI tract - Diffusion – passive movement of molecules through membrane
- Facilitated diffusion – passive movement of molecules through a transporter protein
- Active transport – primary or secondary
iv. Secretion - Ex. skin – sweat & oil
- Ex. digestive juices
b. Structure
i. Polarized cells – each may have different types of transport proteins depending on concentration of materials and direction of movement - Apical surface – faces lumen
- Basolateral – attached to the basement membrane
a. Basement membrane – allows cells to be organized on one surface
ii. Specialized connections - Gap junctions – pore channels between cells that allows communication and movement of materials
- Tight – proteins that tightly bind neighbouring cells; prevent movement of materials between cells
iii. Cell types - Simple – one cell layer
- Stratified – multiple layers
- Squamous – disc/scale
a. Good for diffusion – gas can move across - Cuboidal – cells are often specialized for secretion
a. Ex. Common in kidney tubules & bottom layer of epidermis - Columnar – often specialized for secretion and active transport
a. Differs from cuboidal – often in more difficult environments (ex. lots of acids in small intestine)
iv. In animals - Lungs & gills – one layer of simple squamous
a. Gas exchange between environment and blood vessels - Blood vessel – one layer of simple squamous
a. Gas exchange between tissues and in lungs - Gastrointestinal tract – simple columnar
a. Absorption
b. Protection
c. Specialized cells – good for difficult environment
i. There is a layer of mucous in small intestine that protects cells
ii. Cells die more often – small apical surface area makes it easier for cells to take their place (there are more cells in a smaller space) - Less surface area for damage
- Epidermis
a. Multiple layers
i. Basolateral – (simple) cuboidal
ii. Apical – stratified squamous - Constantly shedding – animals need multiple layers
- Flattening reduces bulk of skin
b. Epidermal derivatives – same tissue type as epidermis
i. Scales
ii. Feathers
iii. Fur - Connective tissues – cells surrounded by extracellular matrix
a. Types
i. Loose – most widespread in vertebrates - Binds epithelia to underlying tissues and holds things in place (ex. skin and organs)
- Loose weave of fibres - collagen and elastin fibres
ii. Fibrous – also dense CT - Tendons and ligaments - holding muscles to bones and bones to bones
- More organized - fibres go the same way which provides more strength
- Mostly extracellular matrix
iii. Adipose – specialized loose CT - Provides padding, insulation, storage
- White areas - vacuoles within cells grow and shrink when fat accumulates within cell
iv. Bone – hard CT - Strong mineralized structure
- Concentric layers of mineralized matrix - circularized layers around cells (mineralized)
v. Cartilage – flexible but strong - Some animals have much more cartilage (ex. sharks)
- Chondrocytes - cells
vi. Blood - Extracellular matrix is fluid - plasma
- Erythrocytes - RBC carry oxygen
- Leukocytes - WBC; immune protection
- Platelets - clotting
- Nervous tissue
a. Cell types
i. Neurons - Dendrites – receive incoming info
- Axon – sends signals out to another neuron; output
- Blood vessels – provides nutrients to neurons
ii. Glia – supporting cells; nourish, replenish, insulate, myelinate - Muscle tissues – actin and myosin enable contraction
a. Skeletal
i. Striated – organized sarcomeres
ii. Formed by fusion of cells – multinucleated
b. Cardiac
i. Separated by intercalated discs – connect muscle fibres together & assists in synchronized contractions
ii. Striated – organized sarcomeres
iii. Involuntary – in all animals
c. Smooth
i. No striations
ii. Involuntary in vertebrates
iii. Voluntary in invertebrates
21
Q
Regulators vs conformers
- thermo
- source of heat
- maintaining body temp
- conserving heat
- osmoregulation
- homeostasis
A
a. Regulation – staying the same; higher energy cost
i. Allows optimal function of proteins and enzymes
ii. Required energy from metabolism
b. Conformation – changes with external environment
i. Required less energy
ii. Proteins may function slightly less – but metabolism is lower functioning so not as many enzymes are required (catch 22 on which one is “better”)
Homeostasis – maintaining a steady state internal environment different from external; active disequilibrium
- Thermoregulation – not always the most clear since different parts of the body can have different temps
a. Homeothermy – constant temp
b. Heterothermy – variable temp - Source of heat – often used
a. Endotherm – heats from inside source through metabolism and catabolic reactions
i. Reactions are purposefully inefficient – heat lost is used
ii. Cooling off – may seek cooler environment (still relies on environmental temp in some ways)
iii. “warm blooded”
b. Ectotherm – heat from outside source; changes with environment
i. “cold blooded” - Maintaining body temp – thermostat mechanism
a. Hypothalamus - senses body temp & deviations outside of set point
i. If too warm – makes adjustments to cool body - Increase in blood vessel dilation in skin – allows heat to be released to environment
- Sweat glands secrete sweat - evaporates cools the body
ii. If too cold - Blood vessel constriction - brings more blood to core to reduce heat loss (less in skin = less that can be lost)
- Shivering - rapid contraction of skeletal muscle; produces heat
- Conservation of heat
a. Insulation – fur, feathers, & blubber add a layer of heat retention
i. All types of insulation change seasonally - Fur gets thicker
- Feathers – down fur
- Blubber – changes for many reasons; more is required in winter
ii. Marine mammals - only have blubber (better in water)
iii. If both on land and sea - blubber and fur - Fur - better on land; traps air and warm air
b. Heat exchangers
i. Ex. Canada geese standing in cold water - Mechanisms in feet that allow heat exchange – countercurrent heat exchange
a. Ret mirable - wonderful net
b. Net of blood vessels – cold blood passes by warm and allows heat exchange
i. Warm blood enters leg in artery - passes heat to blood exiting leg in veins
ii. Cold blood stays in feet - doesn’t cool the core temp of blood
ii. Ex. Killer wales - have in dorsal fin (little blubber here) - Osmoregulation – movement of water to control salt balance
a. Tonicity – non penetrating solutes
i. Requires regulation by water movement – can’t move solutes; only water moves
b. Will differ based on environment
i. Freshwater fish – body fluids are hyperosmotic - Take in a lot of water through gills, skin, gut
- Excretes a lot of water in urine/kidney (lots), gills, skin – prevents cell lysis in hypotonic environment
ii. Marine/salt water – a lot are osmoconformers; body fluids are hypoosmotic - Take in a lot of salts with water through gills, skin, gut
- Excretes a lot of salts through kidney, gills (lots), skin – prevents dehydration of cells
iii. Anadromous – can live in marine or freshwater habitats - Ex. salmon – thermoconformers; require osmoregulation depending on environment
22
Q
Nutrition requirements
A
Cellular work – all cells require ATP produces via cellular respiration; need: - Supply of reactants o Glucose o Oxygen - Waste removal system o Nitrogenous waste o Co2 o H2o – is a “waste” but doesn’t need to be removed because its used in other parts of the body - Mechanism to connect these
Nutrition
- Ingestive heterotrophy – animal eats other organisms to gain energy (can’t produce its own)
o Carbon compounds – ATP synthesis (especially Krebs); macromolecule synthesis
o Essential nutrients – essential AA (can’t be made by body); some fatty acids
o Vitamins & minerals – micronutrients (are only required in small amounts); often play a role in enzyme function
- Deficiencies – can be in everything; there are many symptoms depending on what’s missing
o Ex. lack of glucose – body was breakdown fats, then proteins (using proteins can be harmful)
23
Q
Food processing
A
- Ingestion
a. Mechanical digestion – chewing
i. Not all animals have – often the first step if they do - Ex. starfish & spiders – secrete digestive enzymes onto prey before ingestion
b. Types
i. Suspension feeding – filter feeding - ex, anemone and baleen whale
ii. Substrate feeding – animals live on their food source - Ex. caterpillar
iii. Fluid feeding – very common - Ex. mosquito, aphid
iv. Bulk feeding – ingesting large chunks of food; 2 types - Ingesting whole prey
a. Soft bodied – need to be able to expand
b. Modified jaws
c. Ex. snakes – able to unhinge & separate their jaws - Ingesting prey in pieces
a. Modified teeth – to rip apart and chew prey
b. Derived characteristic – present in more highly evolved animals; adaptations evolved (ex. teeth, claws, etc)
i. Smaller is easier to digest – breakdown occurs more quickly and requires less energy; increased nutrient consolidation
ii. Saliva can access more surface area - Digestion
a. Mechanical digestion – also occurs as churning in stomach (muscle contractions)
b. Chemical digestion – stomach, small intestine
i. Enzymatic hydrolysis
c. Digestive chambers
i. Gastrovascular cavity – present in more basal animals - Organs for digestion and circulation – only one internal cavity
- Only one opening for food and waste – food digests and circulates
ii. Alimentary canal - Digestive tube with 2 opening – complete gut; only travels in one direction
- Components
a. Mouth – mechanical digestion
b. Salivary glands – digestive enzymes for carbs
c. Esophagus – food travels to stomach
d. Stomach – mechanical & chemical digestion
e. Small intestine – chemical digestion & absorption
f. Cecum – fermentation of materials
g. Large intestine – some absorption; mostly reabsorbing water out of digestive material
h. Anus – excretion
i. Pancreas – digestive enzymes
j. Liver – filters blood within food to remove toxins
k. Gallbladder – produces bile for fat breakdown
d. Enzymatic digestion – occurs in one of two places
i. Intracellular – within the cell - Enzymes – within cells (no acid?)
- Sponges – occurs within choanocytes (collar cells)
a. Cell engulfs via phagocytosis – all food is digested this way - Other animals – use for digestion of tripeptides (3 AA proteins)
a. Not very common
ii. Extracellular – enables eating larger pieces of food - Acid and enzymes – within chambers (ex. stomach and sm intestine)
- Almost everything but sponges
e. Start of digestion – all use pancreatic enzymes in small intestine
i. Carbs – begins in oral cavity (salivary amylase)
ii. Proteins – begins in stomach (pepsin)
iii. Fats – beings in small intestine - Absorption
a. Mostly in small intestine – nutrient molecules enter the body cells
i. Small finger like projections – microvilli
ii. Villi – increase SA to increase rate of nutrient absorption and digestion
b. Typhlosole – longitudinal fold projecting into the intestinal cavity
i. Present in less derived species (more basal)
ii. Lengthwise folding increases SA – not as effective or sophisticated as the villi and microvilli - Elimination
24
Q
Feeding and dentition
A
- Mammalian teeth – animals that each chunks will have; there is a lot of variation
a. Incisors – front
b. Canines – lateral to incisors
c. Premolars – anterior to molars
d. Molars – posterior; large SA for grinding - Herbivore (ex. sheep)
a. Cutting incisors – able to cut grass and leaves
b. Canines – modified for slicing; similar to incisors
i. Can be absent
ii. Can be very large – can be for sexual selection as well
c. Pre molars – grinding materials
d. Grinding and pulverizing molars - Omnivore (ex. brown bear)
a. Ex. humans
i. Incisors – breaking off
ii. Canines – were larger in fossil humans; ours are very reduced now
iii. Premolars – pointer than molars; good for sheering
iv. Molars – grinding; mechanical digestion for plant matter - Carnivore (ex. polar bear)
a. Incisors – they’re present but not as useful
b. Canines – capturing and killing
c. Premolars – shearing; fit together well in a way that slides past each other when they chew which helps tear flesh
d. Molars – similar to premolars; less serrated due to lack of space
25
Q
Adaptations to conserve energy during digestion
A
- Parasitism – cestodes (tapeworms)
a. Live in the human gut – small intestine; absorb the nutrients that are released - Mutualistic – microbiome
a. Host of microbes in and on bodies
i. Bacterial infection can change the diversity of microbiome; can cause health issues
ii. Changes over time – infancy to adulthood
iii. Changes based on – breastfed vs formula; vaginal vs c-section
b. Gut bacteria – help break down macromolecules within DI tract
c. Mutually beneficial – place for bacteria to live; helps organisms digest
26
Q
Adaptations to digest cellulose
A
Cellulose – glucose polymer; indigestible by most animals
a. Dietary fibre – part of plant matter
b. Microscopic organisms can digest – assist animals in digestion by living within digestive tract
Solutions to digestion
a. Symbiotic relationships with cellulose digesting bacteria
b. Fermentation chambers in alimentary canals
i. Cecum – pocket between small and large intestine; often where bacteria live in herbivores
ii. Multiple stomachs – crops (pre stomach where mechanical digestion occurs); can live in one or all of the stomachs
iii. Can have both – cows have multiple stomachs and fermentation in cecum
c. Reprocessing food
i. Coprophagy – animals that eat their own feces
1. Rodents and rabbits
2. Bacteria that are useful for cellulose digestion are in large intestine & cecum – they’re lost in feces
3. Eating feces will allow ingestion of cellulose digested by bacteria and reposition the bacteria in small intestine
a. Most absorption occurs in small intestine, not large
d. Organ expansion (comparing herbs and carns of the same size)
i. Larger in herbivores than carnivores:
1. Cecum – for holding fermenting bacteria
2. Large intestine – for greater reabsorption of water and salts
ii. Smaller in herbivores
1. Small intestine – used for absorbing proteins, fats, carbs (more necessary for carnivorous diet)
27
Q
Nitrogenous waste
A
- largest cause of waste removal
- Enzymes remove nitrogen as ammonia in the breakdown of proteins and nucleic acids – very toxic to the body
a. Order of toxicity: ammonia > urea > uric acid
i. Converting to less toxic forms require increasing amounts of energy
ii. Storing as more toxic forms requires more water to be present to dilute to safe levels - Different species convert to different compounds – can change based on environment and throughout lifetime (ex. tadpoles excrete as ammonia living aquatically; frogs store urea)
a. Fish & aquatic animals – excrete as ammonia
i. Free in water – can be continuously eliminated; don’t need to worry about it accumulating
ii. Lots of water required to dilute to non toxic levels within the body
iii. Requires very little energy to convert
b. Mammals – typically convert to urea for storage
i. Requires more water to be present and dilute
ii. Requires more energy to covert than ammonia
c. Birds, insects, land snails – convert to uric acid
i. Requires the least water – least toxic
ii. Largest energy requirements
28
Q
Steps in filtration
A
filtering blood or ISF (if orgs don’t have blood)
- Filtration – BP drives water and solutes from blood into filtrate
- Reabsorption – reclaiming of useful solutes from filtrate back into blood; salts, sugar, hormones, water
- Secretion – adding solutes to filtrate via active transport
- Excretion – urine; filtrate is voided
