Chapter 3 Ecological and Evolutionary Principles Chapter 4

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Chapter 3: Ecological and Evolutionary Principles Chapter 4: Form and Function: The chemical and

Chapter 3: Ecological and Evolutionary Principles Chapter 4: Form and Function: The chemical and physical environment ©Jeffrey S. Levinton 2001

The Ecological Hierarchy • Biosphere: entire set of living organisms and nonliving on the

The Ecological Hierarchy • Biosphere: entire set of living organisms and nonliving on the Earth. • Ecosystem: includes many communities, both abiotic and biotic factors • Community: made of several populations all living in the same place. • Population: group of individuals made of same species. • Individual: is an organism that is independent of other individuals.

Ecological Terms Habitat: place an organism lives (like an address). Habitat is species specific.

Ecological Terms Habitat: place an organism lives (like an address). Habitat is species specific. Niche: function of organism in its habitat or environment (the organism’s job) How do organisms interact with each other? How do marine organisms interact with their environment?

Interactions Between Individuals (Table 3. 1) • • • +- Territoriality +- Predation +

Interactions Between Individuals (Table 3. 1) • • • +- Territoriality +- Predation + - Parasitism ++ Mutualism + 0 Commensalism +- or -- Competition

Territoriality in marine fishes: Below: Clown fish protect and defend anemones that are their

Territoriality in marine fishes: Below: Clown fish protect and defend anemones that are their homes. Above: damsel fish defend territories of coral or algal mats that they farm.

Parasitism • Parasites evolve to reduce damage to host • Commonly involve complex life

Parasitism • Parasites evolve to reduce damage to host • Commonly involve complex life cycles with more than one host • Parasites may invade specific tissues, such as reproductive tissue of the host

Invasion of the parasitic barnacle Sacculina into the body of a crab

Invasion of the parasitic barnacle Sacculina into the body of a crab

Definitive host predation Encysted metacercaria Adult worm defecation Egg 2 nd defecation intermediate hosts

Definitive host predation Encysted metacercaria Adult worm defecation Egg 2 nd defecation intermediate hosts Miracidium Sporocyst 1 st intermediate host Cercaria Redia Complex life cycle found in a trematode parasite living in several marine animal hosts

Mutualism: Cleaner wrasse removes ectoparasites from a number of species of fish that visit

Mutualism: Cleaner wrasse removes ectoparasites from a number of species of fish that visit localized “cleaning stations” on a coral reef. Fish (b) is a mimic species that actually attacks fish that would normally be a “client” of the cleaner wrasse. (a) (b)

Cleaning stations occur in shallow water environments and many types of organisms use them.

Cleaning stations occur in shallow water environments and many types of organisms use them.

Commensalism Commensal crab and fish live in this burrow of Urechis caupo (a worm

Commensalism Commensal crab and fish live in this burrow of Urechis caupo (a worm species)

How do marine animals interact with their environment? (abiotic factors) • Temperature • Salinity

How do marine animals interact with their environment? (abiotic factors) • Temperature • Salinity • Oxygen • Light Measures of organism’s response include: • Behavioral • Physiological • biochemical

Temperature • Temperature variation is common in marine environment: Latitudinal temperature gradient can be

Temperature • Temperature variation is common in marine environment: Latitudinal temperature gradient can be very pronounced (Jordon’s Rule) Seasonal temperature change common Short term changes (e. g. weather changes, tidal changes) • Tolerance to temperature is an important factor in the distribution of marine organisms • Temperature affects growth and reproduction

Temperature for homeotherms • Heat loss - problem for homeotherms who maintain high body

Temperature for homeotherms • Heat loss - problem for homeotherms who maintain high body temperatures Insulation - used by many vertebrates (blubber in whales, feathers in birds) Countercurrent heat exchange circulating venous and arterial blood in opposite directions while vessels are in contact to reduce heat loss

Temperature Countercurrent heat exchange - Heating Chamber 37°C 28 °C 30 °C 32 °C

Temperature Countercurrent heat exchange - Heating Chamber 37°C 28 °C 30 °C 32 °C 34 °C 36 °C 27°C 29 °C 31 °C 33 °C 35 °C 37 °C Example of countercurrent heat retention

Temperature Countercurrent heat exchange in dolphin limb - artery is surrounded by veinlets, which

Temperature Countercurrent heat exchange in dolphin limb - artery is surrounded by veinlets, which return heat veinlets

Temperature Metabolic rate Poikilotherms - can compensate for temperatures by means of acclimation; can

Temperature Metabolic rate Poikilotherms - can compensate for temperatures by means of acclimation; can stabilize metabolic rate over a wide range of intermediate temperature Stabilization of metabolism over wide range of temperature Temperature

Temperature • Freezing - a problem in winter in some environments and in high

Temperature • Freezing - a problem in winter in some environments and in high latitudes where sea ice forms, can destroy cells Some fish have glycoproteins, which function as antifreeze Example: Antarctic fish genus, Trematomus, live in water temps close to – 1. 9 C throughtout the year. These fish die if water temps exceed 6 C!

Antarctic Sea Urchin that produces chemicals to use very little energy (extremely low metabolic

Antarctic Sea Urchin that produces chemicals to use very little energy (extremely low metabolic rates)

Salinity 1 • Salinity change affects organisms because of the processes of diffusion and

Salinity 1 • Salinity change affects organisms because of the processes of diffusion and osmosis

Salinity • Example of osmosis problem - animal with a certain cellular salt content

Salinity • Example of osmosis problem - animal with a certain cellular salt content is placed in water with lower salinity: water will enter animal if it is permeable - cell volume will increase, creating stress • (many marine inverts are permeable)

Salinity % Body volume change • Experiment - Place sipunculid worm Golfingia gouldii in

Salinity % Body volume change • Experiment - Place sipunculid worm Golfingia gouldii in diluted seawater. At first volume increases of worm, but then worm excretes salts, regulating volume back 5 0 1 2 Time (hours)

Salinity 7 • Diffusion - random movement of dissolved substances across a permeable membrane;

Salinity 7 • Diffusion - random movement of dissolved substances across a permeable membrane; tends to equalize concentrations • Problem - diffusion makes it difficult to regulate concentration of physiologically important ions such as calcium, sodium, potassium

Salinity • Most marine organisms have ionic concentrations of cell constituents similar to seawater

Salinity • Most marine organisms have ionic concentrations of cell constituents similar to seawater (see table 4. 1) • Marine organisms such as the Atlantic eel (Anguilla rostrata) can live in both freshwater and saltwater, however most have very narrow tolerance ranges of salinity.

Salinity 11 • Bony fishes - have overall salt concentrations of body fluids of

Salinity 11 • Bony fishes - have overall salt concentrations of body fluids of 1/3 strength of regular seawater. Creates continual osmotic problem of water loss Fish must drink continuously Gills actively secrete salts Sharks employ urea to maintain osmotic balance

Salinity 12 • Bony fishes - osmotic regulation Water exchange Drinking Osmotic loss through

Salinity 12 • Bony fishes - osmotic regulation Water exchange Drinking Osmotic loss through gills Urine Solute exchange Drinking (seawater containing ions) Na+, Cl(gill secretion) Mg 2+, SO 42 -

Oxygen 1 • Most marine organisms require oxygen for manufacture of necessary reserves of

Oxygen 1 • Most marine organisms require oxygen for manufacture of necessary reserves of ATP, energy source in cells • Some habitats are low on oxygen Low tide for many intertidal animals Within sediment - often anoxic pore water Oxygen minimum layers in water column where organic matter accumulates at some depths

Oxygen • Oxygen uptake mechanisms: Animals only a few millimeters thick rely upon diffusion

Oxygen • Oxygen uptake mechanisms: Animals only a few millimeters thick rely upon diffusion for oxygen uptake Larger animals use feathery gills with high surface area to absorb oxygen; mammals have lungs with enormous surface areas to take up oxygen Larger animals have circulatory systems that circulate oxygen to needy tissues. Many have oxygen-carrying blood pigments.

How do marine animals deal with low levels of Oxygen? ? 1. Decrease activity

How do marine animals deal with low levels of Oxygen? ? 1. Decrease activity and therefore O 2 consumption (intertidal crabs) 2. Switch to breathing air: examples include some crabs and mussels (Mytilus californianus consumes O 2 at the same rate in air as water) 3. Use metabolic pathways that do not require O 2 4. Alter blood pigments to carry more O 2 5. Behavioral response to leave the environment.

This species of mussel opens when it is exposed to air and breathes through

This species of mussel opens when it is exposed to air and breathes through its valve.

Light • Many animals detect light with aid of a simple layer of sensory

Light • Many animals detect light with aid of a simple layer of sensory cells, but many species have complex eyes with focusing mechanisms Allows detection of prey, predators Aids in navigation (some animals may use land masses or stars to aid in navigation of long migrations)

 • Eyes of animals: Pinhole camera Nautilus Light Lens Fish Curved, reflective Scallop

• Eyes of animals: Pinhole camera Nautilus Light Lens Fish Curved, reflective Scallop

Scallops and oysters have the ability to detect light and even see images with

Scallops and oysters have the ability to detect light and even see images with reflective sensory organs.

Light • Bioluminescence - light manufactures by organisms - using specialized light organs, sometimes

Light • Bioluminescence - light manufactures by organisms - using specialized light organs, sometimes with the aid of symbiotic bioluminescent bacteria Functions to confuse predators or attract mates Perhaps other as yet undiscovered functions