Communities and Ecosystems - Biology

What is climate?

Long-term patterns of temperature and precipitation in a region.

What factors determine climate?

Solar energy trapped in the biosphere, latitude, heat transport by winds and ocean currents, geographical features, microclimates.

How does solar energy trapped in the biosphere affect climate?

greenhouse gases trap heat, and create a hotter climate.

How does latitude affect climate?

It measures how close a place is to the equator. Closer = warmer. Different types of zones: tropical, temperate, polar.

What are microclimates?

Small-scale climate differences like south facing vs. north facing slopes.

How does climate affect organisms?

It determines which organisms can survive (tolerance ranges), biome type, soil formation.

How does weather affect organisms?

daily activity, migration, feeding, reproduction. Short term stress (heat waves, storms)

What is a niche?

The range of physical and biological conditions in which a species lives and the way the species obtains what it needs to survive and reproduce.

What are the components of a niche?

Abiotic (physical): temp., moisture, humidity, soil type

Biotic (biological): food sources, how it obtains foods, reproduction timing and method, interactions with other organisms.

Resources: water, nutrients, light, food, space, shelter

Tolerance range: optimum range, stress outside optimum, upper/lower limits where survival is impossible

What is a habitat vs. a niche.

Habitat: The place where an organism lives (address)

Niche: the role an organism plays (profession)

What happens when niches overlap?

Competition occurs which leads to resource partitioning, a species dying out, and reduced population sizes.

What is competition?

Organisms use the same limited resource.

What is predation?

Predator kills and eats prey. Controls prey population size. Determines where prey can live.

Herbivory

Animals feed on plants. Shapes plant distribution and abundance.

What are the types of symbiosis and their definitions?

Mutualism: both benefit (increases survival)

Parasitism: parasite benefits, host harmed

Commensalism: one benefits, other is unaffected

What do communities rely on (interdependence)?

Producers (plants, algae), consumers (herbivores, carnivores), decomposers (fungi)

examples of interdependence: nutrient cycling, food webs, habitat creation

What is a keystone species?

A species whose population plays a critical role in structure of a community.
Essential for the stability of a community.

How do communities change over time? Give examples.

Ecological succession. Species alter environment and new species move in. Ex: Glacier Bay forest; Krakatau

What is primary succession?

Starts on bare rock, no soil, pioneer species (lichen).
Soil formation —> grasses —> shrubs —> trees

What is secondary succession?

soil remains, faster, follows wildfire, hurricane, farming

Why does succession occur?

Lichens create soil, plants add organic matter, new species outcompete earlier ones, leads to increased biodiversity over time

what is a biome?

global ecological community defined by climate and organisms.

What are abiotic factors of climate?

temp, precipitation, soil type, sunlight, wind patterns

What are the biotic factors of a climate?

plant life, animal life, adaptations

What are factors that affect aquatic ecosystems?

Sunlight availability: determines photosynthesis, light decreases with depth
nutrient availability: runoff from land
depth and distance from shore: intertidal —> coastal —> open ocean
temp and currents