BIO153: Exam 4

Abiotic v Biotic Factors

Abiotic = nonliving (temperature, light, salinity); Biotic = living influences (organisms)

Community example

All populations living in an area (e.g., coral reef organisms)

Ecological niche

The role of an organism; resources it uses for survival, growth, reproduction

Types of symbiosis

Mutualism, commensalism, parasitism

Mutualism

Both species benefit

Commensalism

One benefits, other unaffected

Parasitism

One benefits, other is harmed

Cleaning symbiosis

Organisms remove parasites from another; both benefit

Predation

One organism kills and eats another

Autotroph V Heterotroph

Autotrophs make food: heterotrophs consume others

Food chain vs food web

Food chain = single pathway; food web = interconnected pathways

Trophic levels

Feeding positions in ecosystem

Primary producers

Autotrophs like phytoplankton

Primary consumers

Herbivores that eat producers

Secondary consumers

Eat primary consumers

Tertiary consumers

Eat secondary consumers

Top predators

Apex predators at top of food chain

Energy transfer between trophic levels

~10% passed to next level

Carnivore

Animal that eats meat

Herbivore

Animal that eats plants/algae

Omnivore

Animal that eats both plants and animals

Sessile vs motile

Sessile = fixed in place; motile = able to move

Nekton vs plankton vs benthos

Nekton = swimmers; plankton = drifters; benthos = bottom dwellers

Pelagic organisms

Organisms that live in the water column

Types of competition

Intraspecific and interspecific

Intraspecific competition

Competition within the same species

Interspecific competition

Competition between different species

Carrying capacity

Maximum population size an environment can support

Resource partitioning

Species use resources differently to coexist

Intertidal zone

Area between high and low tides

Intertidal zones

Spray, high, middle, low tide zones

Rocky shorelines

Found in high wave-energy coasts

Epifauna

Organisms living on surface of substrate

Infauna

Organisms living within substrate

Meiofauna

Tiny organisms living between sediment grains

Intertidal stressors

Desiccation, temperature, salinity, waves, oxygen, space

What fluctuates in intertidal

Temperature, salinity, oxygen, water availability

Filter feeders location

Mostly middle and low intertidal

Grazers location

On rocks scraping algae

Carnivores location

Found throughout zones

Deposit feeders location

In soft sediments

Zonation

Bands of organisms based on environmental tolerance

Limiting resource in intertidal

Often space

Keystone predation

Predator maintains diversity (e.g., sea stars)

Detritus

Dead organic matter

Estuary

Area where freshwater mixes with saltwater

Salinity pattern in estuary

Varies with tides and river input

Salt wedge

Dense saltwater under freshwater layer

Euryhaline

Can tolerate wide range of salinity

Stenohaline

Can tolerate narrow range of salinity

Osmoconformer

Internal salinity matches environment

Osmoregulator

Controls internal salinity

Importance of estuaries

High productivity, nursery habitats, biodiversity

Primary producers in estuaries

Spartina, pickleweed, algae, phytoplankton

Role of detritus

Base of food web in estuaries

Bolsa Chica connection

Example of estuary with salinity gradients and bird habitats

Coral phylum

Cnidaria

Polyp vs medusa

Polyp = attached form; medusa = free-swimming form

Planula

Larval stage of coral

Zooxanthellae role

Symbiotic algae that provide food via photosynthesis

Coral skeleton

Calcium carbonate (CaCO3)

Why corals need shallow water

Need light for photosynthesis

Hard substrate importance

Provides surface for coral attachment

Coral bleaching

Loss of zooxanthellae causing white appearance

Why reefs have high productivity

Efficient nutrient recycling

Coral reef biodiversity

Very high (~25% of marine species)

Coral predators

Crown-of-thorns starfish, parrotfish, butterflyfish

Coral feeding time

Mostly at night

Coral reproduction timing

Linked to lunar cycle

Mesopelagic zone

200-1000 meters depth

Bathypelagic zone

1000-4000 meters

Abyssopelagic zone

4000-6000 meters

Hadal zone

Deepest ocean trenches

Light pattern in ocean

Decreases with depth

Oxygen minimum zone

Low oxygen layer in mesopelagic

Thermocline

Zone of rapid temperature change

Bioluminescence purpose

Camouflage, attract prey, communication

Food availability in deep sea

Very low

Deep-sea adaptations

Large mouths, weak muscles, slow metabolism

Deep scattering layer

Layer of migrating organisms

Pheromones

Chemical signals used for communication

Hermaphroditism

Both male and female reproductive organs

Hydrothermal vent trophic base

Chemosynthetic bacteria

Deep-sea gigantism

Organisms grow unusually large