Unit 2 Ecology

Chapter 2 – Principles of Ecology

Chapter 2 Voc. Word List: Ecology, Biosphere, Abiotic Factors, Biotic Factors, Population, Community, Ecosystem, Habitat, Niche, Symbiosis, Mutualism, Commensalism, Parasitism, Autotrophs, Heterotrophs, Herbivores, Carnivores, Omnivores, Scavengers, Decomposers, Food Chain, Trophic level, Biomass, and Food web

I. Organisms & Their EnvironmentA. Ecology is the study of interactions between organisms and their environmentB. The biosphere is the portion of Earth that supports living things

Living things are found everywhere – air, land, & water

Two factors involved in the biosphere1. Abiotic factors – nonliving parts of an organism’s environment

a. Includes air currents, temperature, moisture, light, soil2. Biotic factors – living organisms that inhabit an environment

b. Includes animals, plants, bacteria, etc.c. organisms are dependent upon other organisms for food, reproduction, and shelter

C. Levels of organization –Remember the Hierarchy of Life Pyramid in Characteristics of Life Notes Organism to Biosphere

1. Populations are groups of organisms of the same speciesa. They compete for the same resources (food, water, mates, etc.)b. Competition is high when resources are low; some species have adaptations to reduce

competition2. Communities are made up of interacting populations in a certain area

a. Changes in one population may cause changes in another population1) Ex.: If the population size of a predator increases, the population size of its

prey will decrease and vice versa3. Ecosystems are made up of interacting populations in a community and the

community’s abiotic factors (main two-precipitation and temperature)

Two major types of Ecosystems 1) Terrestrial ecosystems are located on land (forests, meadows, rotting log)2) Aquatic ecosystems are located in fresh and salt water (ponds, lakes, streams,

oceans)3) Others may include places like the body, buildings, or food

D. Organisms in ecosystems1. A habitat is a place where an organism lives2. A niche is what a species does to survive in its environment (Its role in the ecosystem)

E. Survival relationships1. Symbiosis is the close permanent relationship between different species

a. mutualism – when both species benefit from the relationship (ex. ants and acacia tree)

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b. commensalism – when one species benefits and the other is neither harmed or benefited (ex. moss growing on trees)

c. parasitism – when one species benefits, but the other is harmed (ex. ticks on dogs)1) Parasites do not usually kill the host as it would leave them without a food

source2. Predators seek out and eat other organisms (prey)

II. Nutrition and Energy FlowA. How organisms obtain energy

1. Main source of energy is from the sun2. Autotrophs (Producers) capture this energy to make food through photosynthesis3. Heterotrophs (Consumers) cannot make their own food and must feed on other

organismsa. Herbivores feed on plants (ex. grasshoppers, deer, rabbits)b. Carnivores eat other heterotrophs (ex. lions)c. Omnivores feed on both plants and animals (ex. humans, bears)d. Scavengers feed on dead organisms; have beneficial role in ecosystem (ex. buzzards,

insects)e. Decomposers break down and release nutrients from dead organisms (ex. bacteria)

1) Flow of matter and energy in ecosystema) Energy is trapped by autotrophs and used to make food (matter)b) Matter and energy are passed through the ecosystem through

organisms’ consumption of foodc) A food chain shows how matter and energy move through an

ecosystemEx. berries mice black bear

a. Usually food chains consist of 2, 3, or 4 transfers Smallest is two organisms

b. Each organism represents a trophic level in ecological pyramids2) There are three types of ecological pyramids: energy, numbers, and biomass

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Energy Pyramid

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Biomass Pyramid

Number Pyramid

a.) Biomass is the total amount of organic matter present in a trophic level; is potential food for the next level

b.) Only 10% is transferred from one level to the next

3) Autotrophs make up 1st level4) 1st order heterotroph (2nd level) – feeds on plants5) 2nd order heterotroph (3rd level) – feeds on 1st order heterotrophs6) 3rd order heterotroph (4th level) – feeds on 2nd order heterotrophs7) Some organisms may feed at different levels

c. A food web shows all possible feeding relationships at each trophic level in a community

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Cycles in NatureMatter is never lost; it is recycled

1. In the water cycle, water is cycled through evaporation and condensation Carbon is a fundamental element in the molecules of life (proteins, carbohydrates, fats)

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2. It circulates through the carbon cycle primarily by respiration and photosynthesis, as well as by combustion and decay.

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3. Nitrogen is a necessary element that is circulated by the nitrogen cycle. Nitrogen gas from the air is converted into a usable form for plants by bacteria on the roots of

legumes It is released through waste products and decay.

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4. Phosphorus is cycled in two ways-organic and inorganic Animals obtain phosphorus by eating plants. When they die, the phosphorus returns to the soil Phosphorus is contained in rocks. When the rocks erode, phosphorus is returned to the ecological

system.

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Chapter 3 – Communities and Biomes

Chapter 3 Voc. Word List: Limiting factors, Tolerance, Primary succession, Pioneer species, Climax Community, Secondary succession, Biome, Photic Zone, Aphotic Zone, Estuaries, and Intertidal Zone

I. CommunitiesA. Limiting factors - Any biotic or abiotic factors that restrict the survival of an organism

May include water, food, predators, temperature/climate Tolerance is an organism’s ability to withstand fluctuations in environmental factors

B. Succession- Refers to natural changes that occur in an ecosystem over time Occurs in stages

Two main types Primary succession – colonization of barren land by communities of

organisms Ex.: After a volcano, the cool lava has no living organisms The first inhabitants (pioneer species) are usually lichens These help to make soil from the rock so plants can take hold A climax community is stable and mature and undergoes little change

Secondary succession – series of changes that occur after an existing community is disrupted, such as after a forest fire

C. Biomes -Are major types of ecosystems with distinctive temperatures, rainfall, and organismsTwo major types

1. Aquatic biomes Marine biomes

Water is saline-salty Photic zone – is shallow enough for sunlight to penetrate; contains

plant-life or phytoplankton Aphotic zone – do not receive sunlight; deepest part of ocean Estuaries contain mixed salt and fresh water and are found where

rivers meet the ocean The intertidal zone is the portion of the shoreline that lies between

the high and low tide linesMay vary from place to place, but receives high levels of sunlight, nutrients, and oxygen

Freshwater biomes include ponds, lakes, streams, rivers2. Terrestrial biomes

Climate is determined by latitudinal location on EarthI. The tundra is the coldest land biome

1. Arctic tundra - Most are found at latitudes greater than 55 to 60 North degrees on the coastal plains in the arctic regions of Siberia, northern Europe, Canada, and Alaskaa. Known as a cold desert- cold with the least amount of

rainfall of any biomeb. Form in areas where temperatures are continuously too

low to produce photosynthesis (below 19.4oF (-7oC)) and long periods of low light or darkness

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c. Others factors that cause tundra areas: strong winds, abrasion (type of wind erosion), and low precipitation

d. Underneath the top layer of soil is the permafrost, which is permanently frozen

e. Short growing season 2. Alpine tundra -Worldwide in high elevations (mountainous

and hilly areas) including at the equatora. More rain than the Arctic tundrab. Many have different types of glaciersc. Some areas have permafrost in patches

II. The taiga (coniferous or boreal forest) is south of the tundrao Is warmer and wetter than tundrao Has mostly trees with needles (such as Black Spruce trees)

III. The desert is the driest biome (with the exception of Arctic tundra) with little plant-lifeo Animals are adapted to extreme temperatures and little rainfall

IV. The grasslands have rich soil and grassesV. The temperate forest (deciduous forest) is dominated by hardwood

trees that lose their leaves annuallyVI. The Rain forest

1. Temperate Rainforest are located in areas with lots of rain but cooler temperatures than Tropical Rain forest

a. 2/3 are found in the Pacific Northwest by the Coastal mountain range in Washington, Oregon, and northern California

i. Also located in Canada and parts of Alaskab. Rich soilc. No poisonous snakes

2. Tropical Rain forest are located near the equator o Has warm, wet weathero Has the more diversity of species than any other biome

on Eartho Poor soil o Lots of poisonous snakes

Chapter 4 – Population Biology

Chapter 4 Voc. Word List: Exponential growth, Carrying Capacity, Population density, Density –dependent factors, Density-independent factors, Demography, and Population Growth rate

I. Population DynamicsA. When populations are growing, they exhibit exponential growth (SEE P. 92, FIG. 4.2)

1. As the population gets larger, it grows at a faster rate2. This population growth cannot continue indefinitely

a. Limiting factors slow growth: food availability, predators, lack of space, diseaseb. The population growth stabilizes; deaths will begin to exceed birthsc. Population number will fall to a level that the environment can support (carrying

capacity) (SEE P. 93, FIG. 4.3)

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B. Some organisms (such as mosquitoes) undergo rapid population growth, which declines when conditions become unfavorable

C. Some organisms (such as elephants) have long lives and tend to maintain population sizes at carrying capacity

D. Population density refers to the number of individuals in a particular area1. Organisms can show three patterns of dispersal: random, clumped, uniform2. Density-dependent factors are limiting factors that have a greater effect as the

population increasesa. Include disease, competition, predators, parasites, food

3. Density-independent factors are limiting factors that affect population size regardless of the density

a. Include storms, floods, drought, habitat disruption

II. Human PopulationsA. Human population growth has been rapid since around 1800 due to technological advances

1. Improved medical care/disease prevention2. Increased food production3. Improved water treatment

B. Demography is the study of human population size, density and distribution, movement, and birth/death rates (SEE P. 103, FIG. 4.11)

1. Is based upon information from the census2. Can provide information about a country’s economic and social future

C. Population growth rate is determined by subtracting the death rate per 1000 individuals from the birth rate per 1000 individuals

1. If the birth rate equals the death rate, population growth is zero

Chapter 5 – Biological Diversity/Conservation

Chapter 5 Vocabulary Word List: Biodiversity, Extinction, Endangered species, Threatened species, Habitat loss, Habitat fermentation, Habitat degradation, Acid precipitation, Conservative Biology, Habitat Corridors, Sustainable resources, and Capacity

I. BiodiversityA. Biodiversity refers to the variety of species within a given area

1. Ex. One hectare of a cornfield has less biodiversity than one hectare of a rain forest2. Will differ from place to place on the Earth

B. The higher the biodiversity, the more stable an ecosystem1. The loss of one species will not have as great an impact

C. Extinction occurs when all members of a species have died1. Some extinction occurs naturally2. It is believed that human interference accounts for the increased rates of extinction that

are occurring 3. A species is considered to be endangered when its numbers become so low that

extinction is possible4. A species is considered to be threatened when it is likely to become endangered

D. Threats to biodiversity1. Habitat loss

a. Ex. rain forest, coral reef2. Habitat fragmentation is the separation of wilderness areas from other wilderness areas

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3. Habitat degradation is damage to a habitat by pollutiona. Acid precipitation – has low pH due to sulfur dioxides and nitrogen oxide

combine with water vapor; damages plants, soil, lakesb. Water pollution – degrades aquatic environments; caused by runoff of fertilizers,

animal wastes, detergents, and chemicals, as well as trashc. Land pollution – caused by trash, pesticides, and chemicals

4. Introduction of exotic species (nonnative)a. May lead to loss of other species

II. Conservation of BiodiversityA. Conservation biology – study and implementation of methods to protect biodiversity

1. Based on ecological principles of conserving species and natural resourcesB. Several methods have been implemented

1. U.S. Endangered Species Act (1973) made it illegal to harm endangered or threatened species or its habitat

2. National parks (Yellowstone, Sequoia, etc.) have been established to preserve habitats and communities

3. Habitat corridors allow migration organisms from one wilderness area to another4. Sustainable resources are natural resources that people use that benefit both them and

the ecosystem5. Reintroduction programs involve releasing organisms into area where they once lived 6. Some plant and animal species exist in only captivity

o They may be reintroduced over time, which may be difficult

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