ECOSYSTEMSSC Standard B-6: Students will demonstrate an understanding of the interrelationships among organisms & the biotic & abiotic components of their environment

What is Ecology?• is the scientific study of interactions

among organisms and between organisms & their environment

•Levels of Organization▫Individual organism▫Population ▫Community ▫Ecosystem ▫Biome ▫Biosphere

Ecological Methods1. Observing

▫ used to do basic counts or as 1st step of experiments

2. Experimenting▫ conducted in laboratory or in natural world

3. Modeling ▫ use models to gain insight into large-scale

or complex phenomena ▫ insights gained from studying models often

followed up with further observations & experiments in real world

What is an Ecosystem?•Community: a group of various species that live in

the same habitat & interact with each other

•Ecosystem: a community of organisms & their abiotic environment

What is an Ecosystem?•Biotic factors: describes living factors in an

ecosystem▫Includes dead organisms & the waste of organisms

•Abiotic factors: includes the physical or nonliving factors of an environment▫Examples: rock, air, water, sunlight, climate

Biome•Group of ecosystems with same climate,& similar dominant communities

Biosphere•Part of Earth in which life exists, including: land, water, air (atmosphere)

Biomes of the World

HABITAT

•place where an organism usually lives

BIODIVERSITY

• Includes:1. the variety of organisms in a given area2. the genetic variation within a population3. the variety of species in a community4. the variety of communities in an ecosystem

•Biodiversity is low in habitats with extreme abiotic factors: Artic Circle, Antarctica▫also, the open ocean has low biodiversity▫Areas with low biodiversity can be easily damaged.

•Areas with high biodiversity are more likely to resist damage

What is an Ecosystem?•What are the two ecosystems with the greatest

biodiversity?

What is an Ecosystem?1. Tropical Rainforest2. Coral Reef

SUCCESSION• the replacement of one type of community by

another at a single location over a period of time

Succession• Primary:▫ Starts with bedrock▫ Volcanic island or receding glacier▫ Starts with lichen, mosses (pioneer species)

• Secondary:▫ Starts with soil▫ Example: huge forest fire leaves only soil behind▫ In the soil are organisms, seeds▫ Recovery much shorter▫ Starts with grasses, weeds, shrubs▫ Jack pine requires high temperature for seed to be released

What is an Ecosystem?• Pioneer species: the 1st organisms to appear in a newly

made habitat ▫ example:

new volcanic island receding glacier

▫ Lichens, Mosses

What is Lichen?• It is a mass of fungal & algal cells that grow

together in a symbiotic relationship & that are usually found on rocks or trees

•Symbiosis: a relationship in which 2 different organisms live in a close association with each other

http://www.lichen.com/bigpix/section.html

Lichens•Some colonies estimated to be > 9,000 years old•Uses:▫Antimicrobials▫Dyes ▫Repel herbivores▫Discourage competition from other plants▫Eaten by reindeer & caribou

Primary Succession•After the lichens & mosses have formed soil:

grasses & weeds start to grow shrubs pine trees hard wood trees

•Ecosystems respond to change so that it will be restored to equilibrium

Equilibrium•Sometimes, the ecosystem will find an equilibrium

in which different species dominate after a change.•Example: if rainfall higher than normal one

species of grass dominates the savanna but when there is a drought, a drought-resistant grass dominates

CLIMATE• the average weather conditions in an area over a

long period of time

BIOME•a large region characterized by a specific type of

climate & certain types of plant & animal communities

• 2 key factors of climate that determines biomes are:

1. Temperature2. Precipitation

•Most organisms are adapted to live in a certain range of temperatures and water availability

Terrestrial Biomes• Grouped by latitude into:1. Tropical

Near equator2. Temperate

▫ 30º – 60º3. High-latitude

> 60º

Tropical Biomes• All warm but have differing amounts of rainfall1. Tropical Rainforests

Tropical Rainforest• Layers:

▫ Emergents 100 – 120 ft tall

▫ Canopy Light available at top Little air movement, hi humidity

▫ Understory Layer little light (<3%) Trees have arrested growth until more light becomes available

▫ Forest floor Little growth: light 1%, water scarce

• The most complex in terms of structure & biodiversity

2. Savanna: Tropical Grasslands• Less rain than rainforest• Have long dry seasons followed by short wet season

3. Tropical Deserts• Have very little annual rainfall• Low biodiversity

Temperate Biomes• Have wide range of temperatures• 4 temperate biomes

1. Grasslands2. Forests3. Deserts 4. Rainforest

1. Temperate Grasslands• moderate precipitation▫ Rain & Snow

• cooler temperatures than Savanna

2. Temperate Forests• Deciduous Forests▫ Shed leaves in fall

• Evergreens• Animals:▫ Deer▫ Squirrel▫ Beaver▫ Raccoons

3. Temperate Deserts• cooler than tropical deserts and have wider range of

temperatures

Temperate Rainforest• found in Washington State

Aquatic Biomes: FreshwaterIncludes: ponds

lakesstreamsrivers

Freshwater Biomes

Aquatic Biomes: Wetlands• Include swamps, bayou• Have high biodiversity with many plants, insects,

crustaceans, reptiles, amphibians, birds, fish, and mammals

Aquatic Biomes: Marine Ecosystems• Marine Ecosystems include kelp forests, coral reefs, and

the open ocean• A Kelp Forest:

Aquatic Biomes: Estuaries• Estuary▫ Area where fresh water from rivers & streams mixes with salt

water in seas▫ Organisms adapted to varying concentrations of salt▫ High biodiversity : many fish lay their eggs here, crustaceans,

bivalves

• Mangroves: