ECOLOGYECOLOGY

Ecology• Definition: the scientific study of

interactions among organisms and their environment

– Branch of biology that was developed from natural history

– Study reveals the relationships between living and non-living parts of the world

Biosphere• Definition: portion of Earth that

supports life

– Goes from the top of the atmosphere to the bottom of the ocean

– Supports a wide variety of organisms

Factors Involved• Abiotic: non-living part of an organisms

environment• Air, temperature, moisture, soil, light

• Biotic: all the living organisms that inhabit an environment

Levels of Ecology• Organism: living member of species

• Population: group of organisms of one species that interbreed and live in the same place at the same time

Levels of Ecology• Community: collection of interacting

populations

• Ecosystem: made up of interactions among populations in a community and the communities physical

surroundings

Example……In a desert

• Organism: coyote• Population: pack of coyotes• Community: pack of coyotes, hawks,

owls, snakes, scorpions, & reptiles• Ecosystem: populations of animals

listed above, cacti, shrubs, sand dunes, climate, rocks, temperature

In an ecosystem• Habitat: a place where an organism

lives out its life

• Niche: the role and position a species has in its environment

• How it eats?• How it survives?• How it reproduces?

Succession• Primary Succession: colonization of

new sites by communities of organisms

• Secondary Succession: sequence of community changes that take

place after its disrupted by natural disasters or human action

Relationships• Symbiosis: when species, alike or

different, live together

• Commensalism: one species benefits and the other is neither harmed or benefited

– Like when moss (or plants) grow on a tree

Relationships• Mutualism: both species benefit

– Acacia trees and ants, never found apart

• Parasitism: one species derives a benefit from the other– Fleas and ticks

Nutrition• Autotrophs: organisms that

manufacture their own nutrients using stored energy or energy from

the sun

• Heterotrophs: cannot make their own food, they feed on autotrophs or other heterotrophs

Types of Heterotrophs• Herbivores: feed on plants

– Rabbits, grasshoppers, squirrels, etc

• Carnivores: feed on other animals– Lions, snakes, wolves, etc

• Scavengers: feed on dead animals– Vultures

• Decomposers: break down and absorb nutrients from dead organisms– Fungi and algae

Energy Flow• Food Chain: simple model that shows

how matter and energy move through an ecosystem

Algae Fish Heron

• Trophic Level: each organisms in a food chain represents a feeding step

Algae Fish Heron1st step 2nd step 3rd step

Energy Flow

• Food web: expresses all the possible feeding relationships at each

trophic level in a community– Page 53

Communities• Limiting factors: factors that affect an

organisms ability to survive in its environment

– Food availability, predators, temperature

• Succession: changes over time, species and environment replacements

Biomes

• Definition: large group of ecosystems that share the same community

• Freshwater, marine, and terrestrial

Marine Biomes• Separated into two zones for easier study

– Aphotic: deeper water that never recieves sunlight

– Photic: portion of marine biome shallow enough for light to penetrate

• Tides cause water levels to change

Marine Biomes

• Hundreds of different types of organisms live in the oceans

– From marine plankton in shallow waters to the humpback whales in the deep sea the ocean is full of biodiversity

Freshwater Biomes• Home to different kinds of plants and

organisms– Tadpoles, turtles, insects, lilies, shrubs

• As depth increases, less light penetrates – no photosynthesis and no plants, decomposers at the bottom recycle nutrients

Terrestrial Biomes

• As you move north, south, east, and west around the world

temperature, precipitation, and surroundings change

Tundra• Temperature: long summer days and

short periods of winter

• Plant Life: shallow rooted grasses, small plants

• Soil: underneath soil is called permafrost

• Animals: mosquitoes, lemmings, weasels, foxes, owls, hawks, oxen, caribou, reindeer

Taiga• Temperature: long severe winters,

short summers

• Plant Life: large fir trees, hemlocks, and spruce trees

• Soil: peat swamp habitat

• Animals: lynx, snowshoe hares, caribou – like the tundra

Desert• Temperature: arid, dry, hot

• Plant Life: almost nonexistent, cacti

• Soil: dry, sand dunes

• Animals: coytoes, hawks, owls, snakes, scorpions, and reptiles

Grasslandoccupies more area than any other biome

• Temperature: dry

• Plant Life: grass roots, oats, rye, wheat

• Soil: humus content high, sod underneath

• Animals: bison, wolves, coyotes, rodents, birds, reptiles

Temperate Forest• Temperature: cool winters and

summers there is moderate rainfall

• Plant Life: hardwood trees

• Soil: top layer humus, clay below

• Animals: squirrels, mice, rabbits, deer, birds, bears

Tropical Rainforest• Temperature: warm temperature,

wet surroundings

• Plant Life: deciduous trees, forest plants, lush growth

• Soil: thick wet mat on surface

• Animals: amazing amount of biodiversity

Populations• Population Growth: increase in the

size of a population over time– Does not grow linear, J-shaped growth

• Exponential Growth: as the population gets larger it grows faster

Population Growth

0

200

400

600

Population Size

Time

Growth of Houseflies

Can a population of organisms grow

indefinitely?

NO

Populations (cont)

• Carrying capacity: the number of organisms of one species that

an environment can support

– Under: births exceed deaths– Over: deaths exceed births

Environmental Influences

• Density-dependent factors: disease, competition, parasite, and food

• Density-independent factors: (abiotic) temperature, storms, flood, drought, and habitat disruption

Demography

• Definition: the study of human population growth characteristics

– Study growth rate, age structure, and geographic distribution

Population Vocabulary

• Growth rate: the difference between the birthrate and the death rate

• Fertility rate: the number of offspring a female produces during her

reproductive years

– when high – population grows fast

Population Vocabulary

• Age structure: proportions of a population that are of different levels

– Depicted in graphs– Used to predict if a population is growing

rapidly, slowly, or not at all

Mobility• Immigration: movement of individuals

into a population

• Emigration: movement out of a population

Population Game

• We will simulate a population today. Each person will imitate a

particular trophic level.

• Make sure that you read your “survival cards” before playing. They will be necessary to help you stay alive.

Population Game

Food ChainLions (2 students)

Hyenas (6 students)

Wildebeests (10 students)

Grass (13 students)

Population Game Rules• Make sure that you get all your energy

tokens and water tickets.

• Be careful of how many energy tokens you lose catching prey.

• Upon catching prey – return to Miss Pfeiffer and cash in energy token.

Population Game Rules (2)

• NO TACKLING OR FIGHTING.

• Stay within the boundaries of the “ecosystem”.

• Be sure to follow directions as far as eating different trophic levels.

Biodiversity• Definition: variety of life in an area

– Islands tend to have higher biodiversity– Includes all forms of life, plant and

organism

Importance of Biodiversity

• Nature: life depends on life

– When organisms are removed it affects other organisms

– Must have sufficient numbers in trophic levels

Importance of Biodiversity• People: humans depend on organisms

for their needs

– Oxygen is supplied and CO2 is removed by plants

– Diet – beef, chicken, tuna, shrimp, pork, etc.

– Health – antibiotics supplied by plants

Threats to Biodiversity

• Habitat loss

• Habitat fragmentation

• Abiotic and Biotic Issues

• Habitat Degredation

• Water and land pollution

Conservation of Biodiversity

• Conservation Biology: field of biology that studies methods and

implements plans to protect biodiversity

– Relatively new field of biology– Legal protection for endangered species

implemented by government

Water Cycle

Water Cycle #2

Carbon Cycle

Nitrogen Cycle