Chapter 4 Ecosystems and Communities

Weather: Is the day-to-day conditions of Earth’s

atmosphere. Climate: Average conditions over a long period of

time. What is the climate and weather of Southern

California?

4.1 Climate

All the carbon dioxide builds up in the Earth’s atmosphere, trapping heat.

Greenhouse effect: Natural process that stops all sun’s heat from escaping

rapidly back to space. Without the green houseeffect the Earth would be 30 C cooler.

Solar Energy and the Greenhouse Effect

The Earth’s surface can be divided into different temperate zones based on lines of latitude.

We have 3 different zones….

Tropics: Warmest temperature zone

Polar zones: Coldest temperature zone

Temperate zone: Seasonal changes.

What zone do we live in?

Temperate zone

Why does a crab live in the ocean?

Why does a lion live in the Savanna?

They are all adapted to live in certain places. Tolerance: The ability to survive and reproduce under a

range of environmental circumstances.

4.2 Niches and Community Interactions

Habitat: General place where an organism lives.

Niche: Describes not only what an organism does, but

also how it interacts with biotic and abiotic factors in the environment.

It’s an organisms job.

Resources: Any necessity of life, such as water, nutrients,

light, food, or space.

Niche

What is a plant’s niche?

Photosynthesis and give us oxygen.

What is your niche?

Get good grades…etc

If two people want the same job, what happens?

If there is limited food, what will the two species do?

Compete!

Competitive exclusion: If two species are similar in their requirements that the

same resource limits both species growth, one species may succeed over the other.

Predation: An interaction in which one animal (the

predator) captures and feeds on another animal (the prey).

Herbivory: An interaction in which one animal (the

herbivore) feeds on producers (such as plants).

Predation, Herbivory, and Keystone Species

We have a food chain with sea otters, sea urchins, and kelp. What would happen to the environment if the sea otters died off?

Sea urchin population would increase, while the kelp would decrease.

The sea otter would be considered the keystone specie.

Keystone specie: Can cause dramatic changes in the structure

of a community.

SymbiosisWhat kind of people do you interact with?

Friends Parents Teammates Teachers Coaches Boyfriend/Girlfriend

What kind of relationships do you have with them?

Story

In terms of Gary and I, what kind of relationship did we have?

+,--

In terms of Nicole and I, what kind of relationship do we have?

+,+

What kind of relationship do these organisms have?

Human ___ Mosquito +

What kind of relationship do these organisms have?

Black billed Magpie

+ American Bison

+

Why does the tortoise have a neutral relationship while the rodent and frog are positive?

Gopher Tortoise 0 Rodent + Frog +

These reflect different levels of symbiosis.

Symbiosis: When two species live closely together. There are three main classes of symbiotic

relationships. Mutualism Parasitism Commensalism

Symbiotic Relationships

Parasitism: One organisms benefits, other is harmed. Mutualism: Both organisms benefit Commensalism: One organisms benefits, the other is neither

harmed or benefited

Parasitism

Commensalism

Mutualism

4.3 Succession Ecological Succession: Series of more-or-less predictable changes that occur in

a community over time. Ecosystems change over time, especially after

disturbances, as some species die out and new species move in.

Primary succession: Area with no remnants of an older community.

Pioneer species: The first species to colonize barren areas.

Secondary succession: When disturbances damages an existing community but

leaves soil intact.

Primary Succession

Succession

Secondary Succession 1 Year

Secondary Succession 5 years

Secondary Succession 10 years

Secondary Succession 25 years

Secondary Succession 30 years

Human Caused Disturbances What is happening to trees and forests? Deforestation: Clearing of forests for agriculture.

What do you think about when you hear California?

What do you think about when you hear Antarctica?

4.4 Biomes

Biomes: Defined by abiotic factors like climate and

soil type, and biotic factors like plant and animal life.

Tropical Rainforest Tropical Dry Forest Tropical Grassland/Savanna/Shrubland Desert Temperate Grassland Temperate Woodland and Shrubland Temperate Forest Northwestern Coniferous Forest Boreal Forest Tundra

Examples of Biomes

Warm temperatures, has the most biodiversity and rainfall.

Tall trees form a dense, leafy covering called the canopy.

Shorter trees form the understory.

Tropical Rainforest

Warm; seasonal rainfall; compact soils; frequent fires set by lightning.

Migratory animals such as rhinos and elephants.

Tropical Grassland/Savanna/Shrubland

Least amount of precipitation. Undergo extreme daily temperature

changes. Hot and cold. Cacti are adapted to store water.

Desert

Fertile soils, warm and hot summers, cold winters, and occasional fires.

Temperate Grassland

Deciduous trees: Plants that shed their leaves during a

particular season. Coniferous trees: Produce seed-bearing cones. Cold winters, warm summers, year round

precipitation.

Temperate Forest

Dense coniferous forests, winters are bitterly cold.

Boreal Forest (Taiga)

Permafrost: Permanently frozen subsoil. Strong winds, low precipitation, long cold

dark winters. Not a lot of biodiversity

Tundra

What factors affect life in aquatic ecosystems?

Water depth Temperature Flow Amount of dissolved nutrients

4.5 Aquatic Ecosystems

Who has been to the beach?

What happens to the water color when you get step out to the ocean?

Light areas (photic zone)= light penetrates the water

Dark areas (aphotic zone) = limited light

Water Depth

Can plants live in the aphotic zone?

No, they cannot photosynthesize.

Benthos: Organisms that live in the benthic (shallow)

zone.

Deep Sea Creatures

Can be divided into three main categories

1. Rivers and Streams

2. Lakes an Ponds

3. Freshwater Wetlands

Freshwater Ecosystems

Originate from underground water sources in mountains or hills.

Many animals depend on rivers and streams for food.

Rivers and Streams

Food webs in lakes and ponds often are based on a combination of plankton and attached algae and plants.

Plankton: Includes phytoplankton (plant) and

zooplankton (animal).

Lakes and Ponds

Wetlands: Is an ecosystem in which water either covers

the soil or is present at or near the surface for at least part of the year.

Nutrient rich, highly productive, and serve as breeding grounds for many organisms.

Purify water by filtering pollutants and help prevent flooding.

Freshwater Wetlands

Estuaries Estuaries: Streams and rivers merge with an ocean.

Chesapeake bay!

Serve as spawning and nursery grounds for many ecologically and commercially important fish and shellfish.

Estuaries

Ecologists divide the ocean into three zones based on depth and distance from shore.

Marine Ecosystems

Ocean zones

Intertidal zone: Area of shore between the high-tide and low-

tide lines. Exposed to sun. (closest to land)

Coastal zone: Low-tide out the edge of continental shelf.

Some sunlight. (in between ocean and land)

Open Ocean zone: 90% of the world ocean area. Filled with

zooplankton. (farthest away from land)