Download Unit 2 Ecology

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 Environment
A. Ecology is the study of interactions between organisms and their environment
B. The biosphere is the portion of Earth that supports living things
 Living things are found everywhere – air, land, & water
Two factors involved in the biosphere
1. Abiotic factors – nonliving parts of an
organism’s environment
a. Includes air currents, temperature,
moisture, light, soil
2. Biotic factors – living organisms that inhabit
an environment
a. Includes animals, plants, bacteria, etc.
b. organisms are dependent upon other
organisms for food, reproduction, and
shelter
C. Levels of organization
1. Populations are groups of organisms of the same species
a. They compete for the same resources (food, water, mates, etc.)
b. Competition is high when resources are low; some species have
adaptations to reduce competition
2. Communities are made up of interacting populations in a certain area
a. Changes in one population may cause changes in another population
1) Ex.: If the population size of a predator increases, the
population size of its prey will decrease and vice versa
3. 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
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D. Organisms in ecosystems
1. A habitat is a place where an organism lives
2. A niche is what a species does to survive in its environment (Its role in
the ecosystem)
E. Survival relationships
1. Symbiosis is the close permanent relationship between different species
a. mutualism – when both species benefit from the relationship (ex. ants
and acacia tree)
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 source
2. Predators seek out and eat other organisms (prey)
II.
Nutrition and Energy Flow
A. How organisms obtain energy
1. Main source of energy is from the sun
2. Autotrophs (Producers)capture this energy to make food through
photosynthesis
3. Heterotrophs (Consumers) cannot make their own food and must feed on
other organisms
a. Herbivores feed on plants (ex. grasshoppers, deer, rabbits)
b. Carnivores feed on 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)
B. Flow of matter and energy in ecosystem
1. Energy is trapped by autotrophs and used to make food (matter)
2. Matter and energy are passed through the ecosystem through organisms’
consumption of food
3. A food chain shows how matter and energy move through an ecosystem
berries  mice  black bear
a. Usually consist of 2, 3, or 4 transfers
b. Each organism represents a trophic level in ecological pyramids
2) There are three types of ecological pyramids: energy,
numbers, and biomass (See pp. 52-53)
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 level
4) 1st order heterotroph (2nd level) – feeds on plants
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5) 2nd order heterotroph (3rd level) – feeds on 1st order
heterotrophs
6) 3rd order heterotroph (4th level) – feeds on 2nd order
heterotrophs
7) Some organisms may feed at different levels
b. A food web shows all possible feeding relationships at each trophic
level in a community
C. Cycles in Nature
1. Matter is never lost; it is recycled
2. In the water cycle, water is cycled through evaporation and condensation
(see Fig. 2.17, p. 53)
3. Carbon is a fundamental element in the molecules of life (proteins,
carbohydrates, fats)
a. It circulates through the carbon cycle primarily by respiration and
photosynthesis, as well as by combustion and decay.
4. Nitrogen is a necessary element that is circulated by the nitrogen cycle.
a. Nitrogen gas from the air is converted into a usable form for plants
by bacteria on the roots of legumes
b. It is released through waste products and decay.
5. Phosphorus is cycled in two ways
a. Animals obtain phosphorus by eating plants. When they die, the
phosphorus returns to the soil
b. Phosphorus is contained in rocks. When the rocks erode,
phosphorus is returned to the ecological system.
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.
Communities
A. 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
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 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
organisms
Two 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 lines
May vary from place to place, but receives high
levels of sunlight, nutrients, and oxygen
 Freshwater biomes include ponds, lakes, streams, rivers
2.
Terrestrial biomes
 Climate is determined by latitudinal location on Earth
I. 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 Alaska
a. Known as a cold desert- cold with the
least amount of rainfall of any biome
b. Form in areas where temperatures are
continuously too low to produce
photosynthesis (below 19.4oF (-7oC))
and long periods of low light or darkness
c. Others factors that cause tundra areas:
strong winds, abrasion (type of wind
erosion), and low precipitation
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II.
III.
IV.
V.
VI.
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 equator
a. More rain than the Arctic tundra
b. Many have different types of glaciers
c. Some areas have permafrost in
patches
The taiga (coniferous or boreal forest) is south of
the tundra
o Is warmer and wetter than tundra
o Has mostly trees with needles (such as Black
Spruce trees)
The desert is the driest biome (with the exception of
Arctic tundra) with little plant-life
o Animals are adapted to extreme temperatures
and little rainfall
The grasslands have rich soil and grasses
The temperate forest (deciduous forest) is
dominated by hardwood trees that lose their leaves
annually
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 Alaska
b. Rich soil
c. No poisonous snakes
2. Tropical Rain forest are located near the
equator
o Has warm, wet weather
o Has the more diversity of species than
any other biome on Earth
o Poor soil
o Lots of poisonous snakes
Chapter 4 – Population Biology
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Chapter 4 Voc. Word List: Exponential growth, Carrying Capacity, Population density,
Density –dependent factors, Density-independent factors, Demography, and Population Growth
rate
I.
Population Dynamics
A. 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 rate
2. This population growth cannot continue indefinitely
a. Limiting factors slow growth: food availability, predators, lack of
space, disease
b. The population growth stabilizes; deaths will begin to exceed
births
c. Population number will fall to a level that the environment can
support (carrying capacity) (SEE P. 93, FIG. 4.3)
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 area
1. Organisms can show three patterns of dispersal: random, clumped,
uniform
2. Density-dependent factors are limiting factors that have a greater effect
as the population increases
a. 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 Populations
A. Human population growth has been rapid since around 1800 due to technological
advances
1. Improved medical care/disease prevention
2. Increased food production
3. 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 census
2. 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
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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.
Biodiversity
A. 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 forest
2. Will differ from place to place on the Earth
B. The higher the biodiversity, the more stable an ecosystem
1. The loss of one species will not have as great an impact
C. Extinction occurs when all members of a species have died
1. Some extinction occurs naturally
2. 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 possible
4. A species is considered to be threatened when it is likely to become
endangered
D. Threats to biodiversity
1. Habitat loss
a. Ex. rain forest, coral reef
2. Habitat fragmentation is the separation of wilderness areas from other
wilderness areas
3. Habitat degradation is damage to a habitat by pollution
a. Acid precipitation – has low pH due to sulfur dioxides and
nitrogen oxide combine with water vapor; damages plants, soil,
lakes
b. Water pollution – degrades aquatic environments; caused by runoff
of fertilizers, animal wastes, detergents, and chemicals, as well as
trash
c. 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 Biodiversity
A. Conservation biology – study and implementation of methods to protect
biodiversity
1. Based on ecological principles of conserving species and natural
resources
B. 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
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3. Habitat corridors allow migration organisms from one wilderness area to
another
4. Sustainable resources are natural resources that people use that benefit
both them and the ecosystem
5. 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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