[Virtual Presenter] Biome 4 : Freshwater Streams Part II
(Morris et al., Ch. 48, 34) Who are the consumers in rivers?
BIOLOGY 110Y. 

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BIOLOGY 110Y
Biome 4 : Freshwater Streams Part II
(Morris et al., Ch. 48, 34)
• Who are the consumers in 
rivers?

[Audio] 4. Freshwater Stream Also, in rivers / streams, the carbon cycle overlaps with terrestrial surroundings Leaves will enter the stream Some organisms have life stages in both Terrestrial animals will take prey from the stream (and vice-versa) Animal waste / remains may enter water. 

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Also, in rivers / streams, the 
carbon cycle overlaps with 
terrestrial surroundings
•
Leaves will enter the stream
•
Some organisms have life 
stages in both
•
Terrestrial animals will take 
prey from the stream (and 
vice-versa)
•
Animal waste / remains may 
enter water
4. Freshwater Stream

[Audio] Freshwater Animals as Indicators of Environmental Disruption One-third of all amphibian species are threatened with extinction. Many amphibian species have narrow environmental tolerances and exchange gases through their skin, making them especially sensitive to environmental disruption.. 

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Freshwater Animals as Indicators of Environmental Disruption
•
One-third of all amphibian species are 
threatened with extinction.
•
Many amphibian species have narrow 
environmental tolerances and exchange 
gases through their skin, making them 
especially sensitive to environmental 
disruption.

[Audio] Freshwater Animals as Indicators of Environmental Disruption Habitat destruction, the use of pesticides, and fungal infections have all contributed to amphibian declines These factors, along with invasive species, run off from construction/agriculture/road salt, changes to land use & climate change are changing who is living in our rivers Bioassessment is the identification of living organisms in natural systems to assess if they are "healthy" habitats. 

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Freshwater Animals as Indicators of Environmental Disruption
•
Habitat destruction, the use of pesticides, 
and fungal infections have all contributed to 
amphibian declines
•
These factors, along with invasive species, 
run off from construction/agriculture/road 
salt, changes to land use & climate change 
are changing who is living in our rivers
•
Bioassessment is the 
identification of living 
organisms in natural systems to 
assess if they are “healthy” 
habitats

[Audio] Conservation Biology Diminished biodiversity may make communities less productive and less resilient to fires, hurricanes, or other environmental events Lost species mean lost opportunities for the discovery of novel compounds for medical research, or industries like fishing and travel Humans are connected and rely on the land and its inhabitant – biodiversity loss will change the lives of all peoples. 

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Conservation Biology
•
Diminished biodiversity may make 
communities less productive and less 
resilient to fires, hurricanes, or other 
environmental events
•
Lost species mean lost opportunities for 
the discovery of novel compounds for 
medical research, or industries like fishing 
and travel
•
Humans are connected and rely on the 
land and its inhabitant – biodiversity loss 
will change the lives of all peoples

[Audio] See Ch. 34.5
Subphylum Vertebrata (Craniata) All have a cranium enclosing the brain Cranium, and endoskeleton may be made of cartilage or bone Endoskeleton supports body, allows much larger body size! Muscles attach to endoskeleton to allow movement. 

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Subphylum Vertebrata (Craniata)
• All have a cranium enclosing the brain
• Cranium, and endoskeleton may be made of 
cartilage or bone
• Endoskeleton supports body, allows much 
larger body size!
• Muscles attach to endoskeleton to allow 
movement
See Ch. 34.5

[Audio] Endoskeleton permits larger body size without limiting size of internal body cavity (as exoskeletons do) Cartilage skeleton developed prior to bone Bone is stronger than cartilage, and superior for muscle-tobone attachment. 

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• Endoskeleton permits larger body size without limiting size of 
internal body cavity (as exoskeletons do)
• Cartilage skeleton developed prior to bone
• Bone is stronger than cartilage, and superior for muscle-to-
bone attachment

[Audio] Some Early skeleton were most likely made of cartilage, some lower vertebrates still have only cartilage. 

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• Early skeleton were most 
likely made of cartilage, 
some lower vertebrates still 
have only cartilage
Some

[Audio] Endoskeleton of living hagfishes, lampreys, sharks and their kin, and even some "bony" fishes, such as sturgeons, mostly composed of cartilage Perhaps bone evolved, in part, as a means of mineral regulation Phosphorus and calcium are used for many physiological processes. 

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• Endoskeleton of living hagfishes, lampreys, sharks and their 
kin, and even some “bony” fishes, such as sturgeons, mostly 
composed of cartilage
• Perhaps bone evolved, in part, as a means of mineral 
regulation 
• Phosphorus and calcium are used for many physiological 
processes

[Audio] Major Vertebrate Classes Jawless fishes (hagfish, lamprey) Cartilaginous fishes (Sharks, skates, and rays) Bony fishes (Trout) Amphibians (frogs) Reptiles & Birds Mammals. 

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Major Vertebrate Classes
• Jawless fishes (hagfish, lamprey)
• Cartilaginous fishes (Sharks, skates, and rays)
• Bony fishes (Trout)
• Amphibians (frogs)
• Reptiles & Birds
• Mammals

[Audio] Subphylum Vertebrate (Craniata) A "general" vertebrate physiology is difficult Lots of diversity and different methods for respiration, excretion, feeding, reproduction, etc.
Let's talk Teleosts!!. 

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Subphylum Vertebrate (Craniata)  
• A “general” vertebrate physiology is difficult
• Lots of diversity and different methods for 
respiration, excretion, feeding, reproduction, etc.
Let’s talk Teleosts!!

[Audio] Ray-finned fish fins are supported by bone or spines, connected to skeleton skin over the bone to be "web-like" fin Contrast to lobe-fined fish (left; see Fig.34.30)
"fishes". 

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“fishes”
Ray-finned fish
• fins are supported by bone or spines, 
connected to skeleton
• skin over the bone to be “web-like” fin
• Contrast to lobe-fined fish (left; see Fig.34.30)

[Audio] Ray-finned Fishes (class Actinopterygii) → Teleost fish (infraclass Teleostei) (includes salmon, trout, eels, etc.) Make up 96% of all living fishes ; ½ of all vertebrates Found from high altitudes to great depths Large temperature range (-2o C to 44o C) Marine and freshwater Major characteristic of teleosts: specialized scales, fins, and tails allow exceptional mobility changes in jaw structure allow new types of prey to be caught ** just a few specializations of teleosts. 

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Ray-finned Fishes 
(class Actinopterygii)
 → Teleost fish (infraclass Teleostei)
  
(includes salmon, trout, eels, etc.)
• Make up 96% of all living fishes ; 
 
½ of all vertebrates
• Found from high altitudes to great depths
• Large temperature range (-2o C to 44o C)
• Marine and freshwater
• Major characteristic of teleosts:
• specialized scales, fins, and tails allow 
exceptional mobility 
• changes in jaw structure allow new types of 
prey to be caught
** just a few specializations of teleosts

[Audio] Swim bladder filled with air for buoyancy → gas diffuses in to fill bladder → also involved in sensing. 

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• Swim bladder filled with air for 
buoyancy
→ gas diffuses in to fill bladder
→ also involved in sensing

[Audio] Ancestors were covered in heavy, dermal armour Scales are lighter and allow more mobility More easily capture prey, escape predators Teleost scales overlap (reduce drag in water), and grow by adding outer rings. 

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• Ancestors were covered in heavy, 
dermal armour
• Scales are lighter and allow more 
mobility
• More easily capture prey, escape 
predators
• Teleost scales overlap (reduce drag in 
water), and grow by adding outer rings

[Audio] Feeding In general, most fish spend most of their time searching for food (actually, true of most vertebrates) Evolution of jaws meant new types of food became available (not just filter feeding) Most fish are carnivores – feeding on zooplankton, insect larvae, crustaceans, smaller fish – BUT fish (mostly) cannot chew their food!
– Chewing would block water flow across gills – Most swallow food whole help!. 

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Feeding
• In general, most fish spend most of their time searching for 
food (actually, true of most vertebrates)
• Evolution of jaws meant new types of food became available 
(not just filter feeding)
• Most fish are carnivores – feeding on zooplankton, insect 
larvae, crustaceans, smaller fish
– BUT fish (mostly) cannot chew their food!
– Chewing would block water flow across gills
– Most swallow food whole
help!

Primitive Jaws - No Pucker upper jaw bones upper jaws don't protrude. 

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Primitive Jaws -
No Pucker
upper jaw bones
upper jaws
don't protrude

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[Audio] Reproduction: Most fishes are dioecious (separate sexes) with external fertilization and external development Some are ovoviviparous fish that develop in ovarian cavity → embryo develops in egg, within mother until ready to hatch Some sharks are viviparous with some kind of placental attachment to nourish young → embryo develops with placenta inside mother, until live birth Most oviparous pelagic fish lay huge numbers of eggs → eggs laid with no development of embryo inside mother. 

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Reproduction:
• Most fishes are dioecious (separate sexes) with external 
fertilization and external development
• Some are ovoviviparous fish that develop in ovarian cavity
→ embryo develops in egg, within mother until ready to 
hatch
• Some sharks are viviparous with some kind of placental 
attachment to nourish young
 
→ embryo develops with placenta inside mother, until live 
birth
• Most oviparous pelagic fish lay huge numbers of eggs
 
→ eggs laid with no development of embryo inside mother

[Audio] In Canada, Salmon is king of teleosts! Cultural, economic history of significance Natural stocks continue, but fish farming (aquaculture) has grown in past decades Many implications to conservation of salmon, and surrounding animals. 

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In Canada, Salmon is king of teleosts!
• Cultural, economic history of significance
• Natural stocks continue, but fish farming 
(aquaculture) has grown in past decades
• Many implications to conservation of salmon, 
and surrounding animals

[Audio] In Canada, Salmon is king of teleosts! Salmon are anadromous Grow up in sea, spawn in freshwater 6 species of Pacific salmon and 1 Atlantic salmon migrates Atlantic salmon makes repeated spawning runs Pacific species spawn once and die Atlantic Salmon. 

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In Canada, Salmon is king of teleosts!
•
Salmon are anadromous
• Grow up in sea, spawn in freshwater
•
6 species of Pacific salmon and 1 Atlantic 
salmon migrates 
•
Atlantic salmon makes repeated spawning 
runs
•
Pacific species spawn once and die
Atlantic Salmon

[Audio] Pacific species of sockeye salmon – Migrates downstream – Roams Pacific for 4 years – Returns to spawn in parents' stream – Young fish are imprinted w/ odour of their stream – May navigate to stream mouth by sensing earth magnetic field or angle of the sun, and then smelling their way home Salmon are endangered by stream degradation from logging, farming, pollution and hydroelectric dams. 

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• Pacific species of sockeye 
salmon 
– Migrates downstream
– Roams Pacific for 4 years
– Returns to spawn in parents’ stream
– Young fish are imprinted w/ odour of 
their stream 
– May navigate to stream mouth by 
sensing earth  magnetic field or 
angle of the sun, and then smelling 
their way home
• Salmon are endangered by stream 
degradation from logging, farming, 
pollution and hydroelectric dams

[Audio] tetrapods "four-legged vertebrates"
"fishes". 

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“fishes”
“four-legged vertebrates”
tetrapods

[Audio] Bony Fishes to Tetrapods ~the slow crawl onto land~ 3 features unite bony fishes and tetrapod descendants: Bone replaced cartilage during development Lung or swim bladder is present Evolved as an extension of gut Increased vascularization of the air-filled cavity Double circulation directs deoxygenated blood into the lungs and oxygenated blood out to body Have several unique cranial & dental characters ugh, what stinks?. 

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• 3 features unite bony fishes and tetrapod descendants:
• Bone replaced cartilage during development
• Lung or swim bladder is present 
• Evolved as an extension of gut
• Increased vascularization of the air-filled cavity 
• Double circulation directs deoxygenated blood into 
the lungs and oxygenated blood out to body
• Have several unique cranial & dental characters
ugh, what 
stinks?
Bony Fishes to Tetrapods
~the slow crawl onto land~

[Audio] Bony Fishes to Tetrapods ~the slow crawl onto land~ Characteristics adapted for aquatic habitats, made it possible to explore terrestrial habitats: Air-filled cavity functioned as a swim bladder Paired nares (or nostril) used in chemoreception On land, would be used to draw in air through nares Bony elements of paired fins Modified for support and movement underwater On land, would provide same function hey cuz!. 

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• Characteristics adapted for aquatic habitats, made it 
possible to explore terrestrial habitats:
• Air-filled cavity functioned as a swim bladder
• Paired nares (or nostril) used in chemoreception
• On land, would be used to draw in air through nares
• Bony elements of paired fins
• Modified for support and movement underwater
• On land, would provide same function 
hey cuz!
Bony Fishes to Tetrapods
~the slow crawl onto land~

[Audio] Movement Onto Land is perhaps the most dramatic event in animal evolution Animals are composed mostly of water Land represents a relatively dangerous habitat Vascular plants, pulmonate snails, and tracheate arthropods made transition prior to chordates. 

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Movement Onto Land
is perhaps the most dramatic event in animal evolution
• Animals are composed mostly of water
• Land represents a relatively dangerous habitat
• Vascular plants, pulmonate snails, and tracheate arthropods 
made transition prior to chordates

[Audio] Adaptations included skull, teeth, pectoral girdle and jointed limbs Tetrapods (vs fish)
– Have stronger backbone – Muscles to support the body in air – Muscles to elevate the head – Stronger shoulder and hip girdles – More protective rib cage – Modified ear structure to detect airborne sounds. 

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Adaptations included skull, teeth, 
pectoral girdle and jointed limbs
• Tetrapods (vs fish)
– Have stronger backbone
– Muscles to support the body in 
air
– Muscles to elevate the head
– Stronger shoulder and hip 
girdles
– More protective rib cage
– Modified ear structure to 
detect airborne sounds

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[Audio] Modern Amphibians (Class Amphibia)
Diversity >6000 living species in three orders Remain tied to water Eggs must be kept moist Larvae depend on gills for respiration Challenges faced living terrestrially: Thin skin loses water rapidly → need moist habitat Eggs easily dry out, must be shed into water or kept moist – A few brood young. 

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Modern Amphibians
(Class Amphibia)
Diversity
• >6000 living species in three orders 
• Remain tied to water
• Eggs must be kept moist
• Larvae depend on gills for respiration
Challenges faced living terrestrially:
• Thin skin loses water rapidly → need moist habitat
• Eggs easily dry out, must be shed into water or kept moist
– A few brood young

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[Audio] Salamanders (O. Urodela) ~553 living species, primarily in northern temperate regions Most are small, < 15 cm long Burrowing & some aquatic forms may have lost their limbs Carnivorous as both larvae and adults – Feed on worms, small arthropods, and molluscs Breeding Behavior – Most have aquatic larvae and terrestrial adults Aquatic: lay eggs in clusters or stringy masses Terrestrial: lay eggs in small clusters under logs or in soft earth – Terrestrial species undergo direct development. 

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Salamanders (O. Urodela)
• ~553 living species, primarily in northern 
temperate regions
• Most are small, < 15 cm long
• Burrowing & some aquatic forms may have 
lost their limbs
• Carnivorous as both larvae and adults
– Feed on worms, small arthropods, and molluscs
• Breeding Behavior 
– Most have aquatic larvae and terrestrial adults
• Aquatic: lay eggs in clusters or stringy masses
• Terrestrial: lay eggs in small clusters under logs or in soft earth
– Terrestrial species undergo direct development

[Audio] Frogs and Toads (O. Anura) ~5900 species Must live near water source – Reproduction requires water – Skin is water-permeable skin All have a tailed larval stage (tadpole) and tailless, jumping adults (except for 1 species) Eggs of most hatch into tadpoles with a long, finned tail, no legs, internal and external gills and specialized mouthparts for (usually) herbivorous feeding Tadpoles look and act entirely different from adult frogs. 

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Frogs and Toads (O. Anura)
• ~5900 species  
• Must live near water source
– Reproduction requires water
– Skin is water-permeable skin 
• All have a tailed larval stage (tadpole) and tailless, jumping adults 
(except for 1 species)
• Eggs of most hatch into tadpoles with a long, finned tail, no legs, internal 
and external gills and specialized mouthparts for (usually) herbivorous 
feeding
• Tadpoles look and act entirely different from adult frogs

[Audio] amniotes tetrapods "fishes" eggs are adapted to be laid on land. 

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“fishes”
tetrapods
amniotes
eggs are adapted to 
be laid on land

[Audio] Phylum Mollusca > 90,000 living species / 70,000 fossil species Include snails, slugs, clams, mussels, oysters, squids, octopuses, and nautiluses Still need:
Moisture Shelter Calcium in soil Some may be parasites Prominent Mollusc Classes. 

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Phylum Mollusca
• > 90,000 living species / 70,000 fossil 
species 
• Include snails, slugs, clams, mussels, 
oysters, squids, octopuses, and 
nautiluses
Still need:
Moisture
Shelter
Calcium in soil
Some may be
Prominent Mollusc Classes
parasites

[Audio] Molluscs: basic body characteristics Mantle (folds of skin covering viscera) and mantle cavity produces shell in some molluscs houses gills or lungs; surface acts in gas exchange highly modified in some molluscs. 

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Molluscs: basic body characteristics
Mantle (folds of skin 
covering viscera) and 
mantle cavity
•
produces shell in 
some molluscs
•
houses gills or lungs; 
surface acts in gas 
exchange
•
highly modified in 
some molluscs

[Audio] Molluscs: basic body characteristics Head-foot region - many important functions Well-developed head (mostly…) Radula (rough ribbon-like organ) Foot used for movement →adhesion, extend hydraulically, burrow into mud/sand, finlike for swimming. 

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Molluscs: basic body characteristics
Head-foot region - many 
important functions
• Well-developed head 
(mostly…)
• Radula (rough ribbon-like 
organ)
• Foot used for movement
→adhesion, extend 
hydraulically, burrow 
into mud/sand, fin-
like for swimming

[Audio] Gastropods Largest mollusc class- >70,000 extant sp. Many have shells Tend to be sluggish Shell is one-piece (univalve) May be coiled, or uncoiled Development usually involves: Trochophore stage Veliger stage (shell and foot starts to form) Role in the environment is diverse, includes scrapers of algae, plants (prevent overgrowth), and often prey for many other organisms (birds, mammals, fish, etc.). 

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Gastropods
• Largest mollusc class- >70,000 extant sp.
• Many have shells
• Tend to be sluggish
• Shell is one-piece (univalve)
• May be coiled, or uncoiled
• Development usually involves:
• Trochophore stage
• Veliger stage (shell and foot starts to form)
• Role in the environment is diverse, includes 
scrapers of algae, plants (prevent overgrowth), 
and often prey for many other organisms (birds, 
mammals, fish, etc.)

[Audio] Coiled shells may be:
Right-handed → dextral or Left-handed → sinistral …judged by holding the shell with apex up and aperture facing you!
What's THAT?!
Tough operculum protects soft snail heads. 

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Coiled shells may be:
Right-handed
→ dextral
or
Left-handed
→ sinistral
…judged by holding
the shell with apex up
and aperture facing you!
What’s THAT?!
Tough operculum protects 
soft snail heads

[Audio] Gastropods: feeding Radula → rough ribbon-like organ Found in all molluscs, except bivalves Muscles move radula outwards Used for scraping, piercing, tearing, cutting, boring Two main functions:
1. scrape food particles from hard surfaces 2. act as a conveyor belt to move food towards stomach. 

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Radula  → rough ribbon-like organ
• Found in all molluscs, except bivalves
• Muscles move radula outwards
• Used for scraping, piercing, tearing, 
cutting, boring
• Two main functions:
1. scrape food particles from hard 
surfaces
2. act as a conveyor belt to move food 
towards stomach
Gastropods: feeding

[Audio] Gastropods: feeding Well defined head & mouth Radula is a toothy ribbon that is key for collecting food What "food" is, can be variable…. 

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Gastropods: feeding
• Well defined head & mouth
• Radula is a toothy ribbon that is 
key for collecting food
• What “food” is, can be 
variable…

[Audio] Gastropods: feeding Most are herbivores scraping algae off of surfaces foraging for green vegetation (i.e. land snails) Some are scavengers, feeding on dead and decaying organic matter Marine snails: Some are parasites of corals Some are predators Martinell et al., 2010; Palaios Use radula to tear at their prey Bore holes into shells of shelled prey, and a proboscis to feed on soft tissue. 

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Gastropods: feeding
• Most are herbivores
• scraping algae off of surfaces
• foraging for green vegetation (i.e. land 
snails)
• Some are scavengers, feeding on dead and 
decaying organic matter
Marine snails:
• Some are parasites of corals
• Some are predators
• Use radula to tear at their prey
• Bore holes into shells of shelled prey, and 
a proboscis to feed on soft tissue
Martinell et al., 2010; 
Palaios

[Audio] Gastropods: Respiration and Reproduction Respiratory organs found in mantle cavity →ctenidia (primitive gill) →secondary gill, or →lungs in some gastropods. 

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Gastropods: Respiration and Reproduction
• Respiratory organs found in mantle cavity
 
→ctenidia (primitive gill)
 
→secondary gill, or
 
→lungs in some gastropods

[Audio] Gastropods: Reproduction: dio- or monoecious (hermaphrodite)
→Fertilization in water, trochophore within the egg →Shelled eggs may be released to water column or attached to surface, veliger emerge →Terrestrial and some freshwater gastropods fertilize internally, within oviduct →Young snails emerge from eggs but other life stages occur inside egg. 

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Gastropods:
• Reproduction: dio- or monoecious (hermaphrodite)
→Fertilization in water, trochophore within the egg
→Shelled eggs may be released to water column or attached to 
surface, veliger emerge
→Terrestrial and some freshwater gastropods fertilize internally, 
within oviduct
→Young snails emerge from eggs but other life stages occur inside 
egg

[Audio] Gastropods: Diversity Terrestrial gastropods land "snails" have shells land "slugs" have no shells both are air breathers, and have opening to "lung" visible. 

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Gastropods: Diversity
Terrestrial gastropods
•
land “snails” have shells
•
land “slugs” have no shells
•
both are air breathers, and have opening 
to “lung” visible

[Audio] Gastropods: Diversity Freshwater snails Numerous species/lineages that have successfully adapted to freshwater Most have shells Some breathe using gills, some surface to breathe air using lungs Important in some cultural cuisines (food)… and human health Some parasites use snails hosts. 

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Gastropods: Diversity
Freshwater snails
•
Numerous species/lineages that have 
successfully adapted to freshwater
•
Most have shells
•
Some breathe using gills, some surface 
to breathe air using lungs
•
Important in some cultural cuisines 
(food)… and human health
•
Some parasites use snails hosts

[Audio] https://www.invadingspecies.com/invad ers/invertebrates/invasive-snails-2/. 

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https://www.invadingspecies.com/invad
ers/invertebrates/invasive-snails-2/

[Audio] Bivalves ~ 9,000 extant sp. Most are marine, also freshwater and brackish water Most are sedentary filter feeders Create water currents using cilia on their specialized gills No defined head No radula Very little cephalization (clustering of nervous tissue toward one end). 

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Bivalves
• ~ 9,000 extant sp.
• Most are marine, 
also freshwater and brackish water
• Most are sedentary filter feeders
• Create water currents using cilia on 
their specialized gills
• No defined head
• No radula
• Very little cephalization 
  (clustering of nervous tissue toward one end)

[Audio] Bivalves 2 valves held together by a hinge ligament Valves are drawn together by strong adductor muscles Resting state is shell open Fig. 34.14. 

Scene 48

Bivalves
Fig. 34.14
• 2 valves held together by 
a hinge ligament
• Valves are drawn 
together by strong 
adductor muscles
• Resting state is shell 
open

Scene 49

[Audio] Umbo is oldest part of the shell, growth occurs an rings Pearls produced when an irritant is lodged between the shell and mantle – Layers of nacre secreted around the foreign material. 

Scene 50

Bivalve Shell
• Umbo is oldest part of the 
shell, growth occurs an 
rings
• Pearls produced when an 
irritant is lodged between 
the shell and mantle
– Layers of nacre 
secreted around
 
 the foreign material

BIOL 110 Freshwater Streams Part 2

avatar

4. Freshwater Stream Also, in rivers / streams, the  carbon cycle overlaps with  terrestrial surroundings 

Leaves will enter the stream 

Some organisms have life  stages in both 

Terrestrial animals will take  prey from the stream (and  vice versa)


Animal waste / remains may  enter water

Freshwater Animals as Indicators of Environmental Disruption 

One third of all amphibian species are  threatened with extinction.


Many amphibian species have narrow  environmental tolerances and exchange  gases through their skin, making them  especially sensitive to environmental  disruption.

Freshwater Animals as Indicators of Environmental Disruption 

Habitat destruction, the use of pesticides,  and fungal infections have all contributed to  amphibian declines 

These factors, along with invasive species,  run off from construction/agriculture/road  salt, changes to land use & climate change  are changing who is living in our rivers 

Bioassessment is the  identification of living  organisms in natural systems to  assess if they are "healthy"  habitats

Conservation Biology 

Diminished biodiversity may make  communities less productive and less  resilient to fires, hurricanes, or other  environmental events 

Lost species mean lost opportunities for  the discovery of novel compounds for  medical research, or industries like fishing  and travel 

Humans are connected and rely on the  land and its inhabitant – biodiversity loss  will change the lives of all peoples

See Ch. 34.5
Subphylum Vertebrata (Craniata)

 All have a cranium enclosing the brain 
 Cranium, and endoskeleton may be made of  cartilage or bone 
 Endoskeleton supports body, allows much  larger body size!

 Muscles attach to endoskeleton to allow  movement

Endoskeleton permits larger body size without limiting size of  internal body cavity (as exoskeletons do)

 Cartilage skeleton developed prior to bone 
 Bone is stronger than cartilage, and superior for muscle tobone attachment

Some 
 Early skeleton were most  likely made of cartilage,  some lower vertebrates still  have only cartilage

Endoskeleton of living hagfishes, lampreys, sharks and their  kin, and even some "bony" fishes, such as sturgeons, mostly  composed of cartilage 
 Perhaps bone evolved, in part, as a means of mineral  regulation  
 Phosphorus and calcium are used for many physiological  processes

Major Vertebrate Classes 
 Jawless fishes (hagfish, lamprey)

 Cartilaginous fishes (Sharks, skates, and rays)

 Bony fishes (Trout)

 Amphibians (frogs)

 Reptiles & Birds 
 Mammals

Subphylum Vertebrate (Craniata)   
 A "general" vertebrate physiology is difficult 
 Lots of diversity and different methods for  respiration, excretion, feeding, reproduction, et cetera
Let's talk Teleosts!!

Ray finned fish 
 fins are supported by bone or spines,  connected to skeleton 
 skin over the bone to be "web like" fin 
 Contrast to lobe fined fish (left; see Fig.34.30)
"fishes"

Ray finned Fishes  (class Actinopterygii) → Teleost fish (infraclass Teleostei)   (includes salmon, trout, eels, et cetera)

 Make up 96% of all living fishes ;   ½ of all vertebrates 
 Found from high altitudes to great depths 
 Large temperature range (-2o C to 44o C)

 Marine and freshwater 
 Major characteristic of teleosts:

 specialized scales, fins, and tails allow  exceptional mobility  
 changes in jaw structure allow new types of  prey to be caught ** just a few specializations of teleosts

Swim bladder filled with air for  buoyancy → gas diffuses in to fill bladder → also involved in sensing

Ancestors were covered in heavy,  dermal armour 
 Scales are lighter and allow more  mobility 
 More easily capture prey, escape  predators 
 Teleost scales overlap (reduce drag in  water), and grow by adding outer rings

Feeding 
 In general, most fish spend most of their time searching for  food (actually, true of most vertebrates)

 Evolution of jaws meant new types of food became available  (not just filter feeding)

 Most fish are carnivores – feeding on zooplankton, insect  larvae, crustaceans, smaller fish – B-U-T fish (mostly) cannot chew their food!
– Chewing would block water flow across gills – Most swallow food whole help!

Reproduction:

 Most fishes are dioecious (separate sexes) with external  fertilization and external development 
 Some are ovoviviparous fish that develop in ovarian cavity → embryo develops in egg, within mother until ready to  hatch 
 Some sharks are viviparous with some kind of placental  attachment to nourish young  → embryo develops with placenta inside mother, until live  birth 
 Most oviparous pelagic fish lay huge numbers of eggs  → eggs laid with no development of embryo inside mother

In Canada, Salmon is king of teleosts!

 Cultural, economic history of significance 
 Natural stocks continue, but fish farming  (aquaculture) has grown in past decades 
 Many implications to conservation of salmon,  and surrounding animals

In Canada, Salmon is king of teleosts!


Salmon are anadromous 
 Grow up in sea, spawn in freshwater 

6 species of Pacific salmon and 1 Atlantic  salmon migrates  

Atlantic salmon makes repeated spawning  runs 

Pacific species spawn once and die Atlantic Salmon

Pacific species of sockeye  salmon  – Migrates downstream – Roams Pacific for 4 years – Returns to spawn in parents' stream – Young fish are imprinted w/ odour of  their stream  – May navigate to stream mouth by  sensing earth  magnetic field or  angle of the sun, and then smelling  their way home 
 Salmon are endangered by stream  degradation from logging, farming,  pollution and hydroelectric dams

tetrapods "four legged vertebrates"
"fishes"

Bony Fishes to Tetrapods ~the slow crawl onto land~

 3 features unite bony fishes and tetrapod descendants:

 Bone replaced cartilage during development 
 Lung or swim bladder is present  
 Evolved as an extension of gut 
 Increased vascularization of the air filled cavity  
 Double circulation directs deoxygenated blood into  the lungs and oxygenated blood out to body 
 Have several unique cranial & dental characters ugh, what  stinks?

Bony Fishes to Tetrapods ~the slow crawl onto land~

 Characteristics adapted for aquatic habitats, made it  possible to explore terrestrial habitats:

 Air filled cavity functioned as a swim bladder 
 Paired nares (or nostril) used in chemoreception 
 On land, would be used to draw in air through nares 
 Bony elements of paired fins 
 Modified for support and movement underwater 
 On land, would provide same function  hey cuz!

Movement Onto Land is perhaps the most dramatic event in animal evolution 
 Animals are composed mostly of water 
 Land represents a relatively dangerous habitat 
 Vascular plants, pulmonate snails, and tracheate arthropods  made transition prior to chordates

Adaptations included skull, teeth,  pectoral girdle and jointed limbs 
 Tetrapods (vs fish)
– Have stronger backbone – Muscles to support the body in  air – Muscles to elevate the head – Stronger shoulder and hip  girdles – More protective rib cage – Modified ear structure to  detect airborne sounds

Modern Amphibians (Class Amphibia)
Diversity 
 >6000 living species in three orders  
 Remain tied to water 
 Eggs must be kept moist 
 Larvae depend on gills for respiration Challenges faced living terrestrially:

 Thin skin loses water rapidly → need moist habitat 
 Eggs easily dry out, must be shed into water or kept moist – A few brood young

Salamanders (O. Urodela)

 ~553 living species, primarily in northern  temperate regions 
 Most are small, < 15  centimeters long 
 Burrowing & some aquatic forms may have  lost their limbs 
 Carnivorous as both larvae and adults – Feed on worms, small arthropods, and molluscs 
 Breeding Behavior  – Most have aquatic larvae and terrestrial adults 
 Aquatic: lay eggs in clusters or stringy masses 
 Terrestrial: lay eggs in small clusters under logs or in soft earth – Terrestrial species undergo direct development

Frogs and Toads (O. Anura)

 ~5900 species   
 Must live near water source – Reproduction requires water – Skin is water permeable skin  
 All have a tailed larval stage (tadpole) and tailless, jumping adults  (except for 1 species)

 Eggs of most hatch into tadpoles with a long, finned tail, no legs, internal  and external gills and specialized mouthparts for (usually) herbivorous  feeding 
 Tadpoles look and act entirely different from adult frogs

amniotes tetrapods "fishes" eggs are adapted to  be laid on land

Phylum Mollusca 
 > 90000 living species / 70000 fossil  species  
 Include snails, slugs, clams, mussels,  oysters, squids, octopuses, and  nautiluses Still need:
Moisture Shelter Calcium in soil Some may be parasites Prominent Mollusc Classes

Molluscs: basic body characteristics Mantle (folds of skin  covering viscera) and  mantle cavity 
 produces shell in  some molluscs 
 houses gills or lungs;  surface acts in gas  exchange 
 highly modified in  some molluscs

Molluscs: basic body characteristics Head foot region  many  important functions 
 Well developed head  (mostly…)

 Radula (rough ribbon like  organ)

 Foot used for movement →adhesion, extend  hydraulically, burrow  into mud/sand, finlike for swimming

Gastropods 
 Largest mollusc class >70000 extant sp.

 Many have shells 
 Tend to be sluggish 
 Shell is one piece (univalve)

 May be coiled, or uncoiled 
 Development usually involves:

 Trochophore stage 
 Veliger stage (shell and foot starts to form)

 Role in the environment is diverse, includes  scrapers of algae, plants (prevent overgrowth),  and often prey for many other organisms (birds,  mammals, fish, et cetera)

Coiled shells may be:
Right handed → dextral or Left handed → sinistral …judged by holding the shell with apex up and aperture facing you!
What's THAT?!
Tough operculum protects  soft snail heads

Gastropods: feeding Radula  → rough ribbon like organ 
 Found in all molluscs, except bivalves 
 Muscles move radula outwards 
 Used for scraping, piercing, tearing,  cutting, boring 
 Two main functions:
1. scrape food particles from hard  surfaces 2. act as a conveyor belt to move food  towards stomach

Gastropods: feeding 
 Well defined head & mouth 
 Radula is a toothy ribbon that is  key for collecting food 
 What "food" is, can be  variable…

Gastropods: feeding 
 Most are herbivores 
 scraping algae off of surfaces 
 foraging for green vegetation (in other words land  snails)

 Some are scavengers, feeding on dead and  decaying organic matter Marine snails:

 Some are parasites of corals 
 Some are predators Martinell and others, 2010;  Palaios 
 Use radula to tear at their prey 
 Bore holes into shells of shelled prey, and  a proboscis to feed on soft tissue

Gastropods: Respiration and Reproduction 
 Respiratory organs found in mantle cavity  →ctenidia (primitive gill)  →secondary gill, or  →lungs in some gastropods

Gastropods:

 Reproduction: dio or monoecious (hermaphrodite)
→Fertilization in water, trochophore within the egg →Shelled eggs may be released to water column or attached to  surface, veliger emerge →Terrestrial and some freshwater gastropods fertilize internally,  within oviduct →Young snails emerge from eggs but other life stages occur inside  egg

Gastropods: Diversity Terrestrial gastropods 
 land "snails" have shells 
 land "slugs" have no shells 
 both are air breathers, and have opening  to "lung" visible

Gastropods: Diversity Freshwater snails 

Numerous species/lineages that have  successfully adapted to freshwater 

Most have shells 

Some breathe using gills, some surface  to breathe air using lungs 

Important in some cultural cuisines  (food)… and human health 

Some parasites use snails hosts

invadingspecies ers/invertebrates/invasive snails-2/

Bivalves 
 ~ 9000 extant sp.

 Most are marine,  also freshwater and brackish water 
 Most are sedentary filter feeders 
 Create water currents using cilia on  their specialized gills 
 No defined head 
 No radula 
 Very little cephalization   (clustering of nervous tissue toward one end)

Bivalves 
 2 valves held together by  a hinge ligament 
 Valves are drawn  together by strong  adductor muscles 
 Resting state is shell  open Fig. 34.14

Umbo is oldest part of the  shell, growth occurs an  rings 
 Pearls produced when an  irritant is lodged between  the shell and mantle – Layers of nacre  secreted around  the foreign material