Download Ecology Ch. 3-4

Principles of Ecology
 What is ecology?
 The study of the interactions between
organisms and the living and nonliving
components of their environment
 Involves collecting information about organisms and
their environment
 Issues dealing with Ecology
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Thinning ozone layer
Climate changes (greenhouse effect)
Habitat destruction
Pollution
Levels of Organization
 Biome
 Large areas characterized by climate conditions and plant
life
 Temperate Grassland
 Ecosystem
 Includes all of the organisms and the non living environment
found in a particular place
 Ex. Ponds, bottom of shoe, deep oceans, rain forests
 Community
 All the interacting organisms living in an area
 Ex. All the fish, turtles, plants, algae, and bacteria in a pond
 Population
 A group of the same species that lives in one area
 All the painted turtles in a pond
 Organism
 An individual living thing
 A painted turtle
Biotic and Abiotic Factors
 Habitat is where an organism lives
 Includes abiotic and biotic factors
 Biotic factors include all living things that affect the organism
 Ex. Animals, plants, algae, fungi, bacteria
 Abiotic factors are nonliving factors which are the physical
and chemical characteristics of the environment
 Ex. Temperature, humidity, pH, salinity, oxygen
concentration, amount of sunlight, availability of nitrogen
in the soil affects how fast plants can grow
 Biotic and abiotic determine the survival and growth of
an organism, productivity of the ecosystem in which
organism lives
Producers
 What is the main energy source for life on Earth?
 What are producers?
 Organisms that capture energy and use it to make food
 Also known as autotrophs
 Examples
 Photosynthesis-light energy is used to power chemical
reactions
 CO₂ and H₂O are converted into O₂ and sugars
 Plants, algae, cyanobacteria
 Chemosynthesis-convert energy from chemical bonds within
inorganic molecules into chemical energy
 Use hydrogen sulfide and convert it into carbohydrates
 Bacteria
 Volcanic vents on deep ocean floors, hot springs, tidal marshes
Types of Consumers
 Heterotroph- organisms that rely on other
organisms for their energy and food supply
 Consumer
 Many types of heterotrophs
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Herbivores eat only plants
Carnivores eat animals
Omnivores eat both plants and animals
Detritivores eat plant and animal remains,
and other dead organic matter
 Decomposers break down organic matter
 Decomposers are essential for autotrophs to
obtain their necessary nutrients
Feeding Relationships
 What happens to the energy in an ecosystem?
 Flows through ecosystem in one direction
 Starts with sun to various consumers
 Food chain- steps showing the transfer of energy
from organism to organism
 Producer-pri consumer- sec consumer- tertiary
consumer
 https://www.youtube.com/watch?v=0ZOvqYypOuo
 Food web- network of complex interactions,
among organisms in community from producers
to decomposers
 linking all food chains in an ecosystem together
Trophic Levels
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Trophic levels- levels of
nourishment in a food chain
Each step in food chain or food
web=trophic
Ecological pyramids- shows the
relative amount of energy available
at each trophic level
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Organisms use about 10% of this
energy for life processes, rest is lost
as heat
Respiration, movement, reproduction
Most ecosystems contain only 3 or
4 trophic levels
First level-Producers
Second level-Herbivore
Third level-Predators
Biomass- total amount of living
tissue w/in given trophic level
 All organisms need energy to carry out essential
functions
 Ex. Growth, movement, maintenance, repair and
reproduction
 The amount of energy an ecosystem receives and
the amount that is transferred from organism to
organism has an important effect on the
ecosystem’s structure
Niche
 Habitat is where an organism lives
 Includes abiotic and biotic factors
 What is an ecological niche?
 All the physical, chemical, and biological factors that a species
needs to survive, stay healthy, and reproduce
 It is a species way of life, or the role the species plays in its
environment
 Includes the range of conditions that the species can tolerate
 How it obtains food, competes with others, fits into food web
 When is it active and reproduces
 Competitive exclusion- when two species are competing for
same resources, one species will be better suited to niche,
other species will pushed into another niche or become
extinct
 Ecological equivalents- species that occupy similar niches
but live in different geographical regions
Community Ecology
 5 major types of close interactions can powerfully affect
an ecosystem
 Predation, parasitism, competition, mutualism, and
commensalism
 Competition- occurs when organisms of the same or
different species attempt to use a resource in same place at
same time
 Predation- interaction where one organism captures and
feeds on another organism
 Predator- higher on food chain
 Prey- lower on food chain
 Symbiosis- any relationship where 2 species are living
closely together
 3 types- mutualism, commensalism, parasitism\
 Discovery Education
Types of Symbiotic
Relationships
 Mutualism- relationship where both
species benefits
 Commensalism- relationship where one
specie benefits and others is not helped
or harmed
 Parasitism- relationship where one
organism lives on or inside other
organism and harms it
 Write down which relationship is being
shown
 Lions and zebras
 Honey bee pollinates flower
 Remora fish attaches itself to other shark
and eats the food that is dropped by
shark
 Lions and cheetahs
 Mosquito bites humans
Population Ecology
 Why do populations
change?
 Population densitynumber of individuals
per unit area
 Depends on species
and its ecosystem
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# of individuals= population density
area (units^2)
 Population dispersion- way in
which individuals of a
population are spread in an
area or volume
Population Growth
 What factors affect population size?
 # of births, # of deaths, and # of individuals
that enter and leave the population
 Immigration- the movement of individuals
into an area
 Emigration- the movement of individuals
out of an area
 What causes these movements?
 Young animals reach maturity search for mates,
shortage of food
Exponential Growth
 Individuals in a
population reproduce at
a constant rate
 Under ideal conditions
with unlimited
resources, and in the
absence of predation and
disease, a population will
grow exponentially
Logistic Growth
 A population’s growth slows
or stops following a period
of exponential growth
 Why might this happen?
 Resources become less
available
 Carrying capacity- the largest
number of individuals that a
given environment can support
 Many natural populations
follow the logistic growth curve
Ecological Factors that
limits to Growth
 Limiting factors- factor that causes population
growth to decrease
 A resource can also affect long term survival of a
species
 Pandas
 Density-dependent factors- limiting factor that
depends on population size
 Factors greatly affect large and dense
populations
 Factors include; competition, predation,
parasitism, and disease
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Competition may occur between
individuals of same species or of
different species
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Predation- often controls
populations in nature
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The more individuals the faster
the resources are used up
Competition between different
species leads to evolutionary
change
Moose populations rise, wolves
population soon rises. Moose
populations soon decrease, later
followed by the decline in wolves
Parasitism and disease- range in
size, similar to predators, take
nourishment from host,
weakening or causing death to
them
 Density-Independent Factors- affect all
populations in similar ways, regardless of
population size
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Unusual weather
Natural disasters
Seasonal cycles
Certain human activities- clearing forests,
damming rivers
 Environments are always changing, most
populations can adapt to certain amount of
change
Ecological Succession
 Ecosystems are constantly changing in response to natural and
human disturbances, as ecosystem changes, older inhabitants
gradually die out and new organism move in, causing further
changes in community
 These predictable changes that occurs in community over time=
ecological succession
 Primary succession- succession that occurs on surface where no
soil exists
 Volcanic eruption builds new island- Hawaii
 Pioneer species- 1st organisms that live in previously uninhabited area
 Secondary succession- succession that occurs after natural
events or human activities, after disturbance community
interactions restore the ecosystem
 Wildfires
Sec 3- Cycles of Matter
 95% of body made up of 4 elements
 Matter is recycled within and between
ecosystems
 Biogeochemical cycles- the passing of
elements, compounds and other forms of
matter from one organism to another
 Each substance travels through a
biogeochemical cycle-moving from the abiotic
portion of the environment, such as the
atmosphere, into living things and back again
Water Cycle and Nutrient
Cycles
 4 important processes of the water cycle
 Evaporation, transpiration, condensation, precipitation
 The amount of water the atmosphere can hold
depends on temperature and air pressure
 Nutrient cycles- every organism needs nutrients
 Build tissues, carry out essential life function
 Carbon, nitrogen, phosphorus, oxygen
 The basis of the carbon cycle is photosynthesis
and cellular respiration
 Plants use carbon dioxide
 3 major sources of CO2-cellular respiration, combustion,
and decomposition of organic matter
Nitrogen Cycle
 Nitrogen is essential for organisms to make
proteins and nucleic acids
 Makes up 78% of atmosphere
 Plants can only use nitrate
 Nitrogen fixation is the process of converting
nitrogen gas to nitrate (ammonia)
 How does this happen?
 Bacteria
 Live in soil or in the roots of plants
 Denitrification- nitrates converted into nitrogen gas
Phosphorus Cycle
 Forms part of DNA and RNA
 Not found in atmosphere, found mostly in
rock and soil minerals, ocean sediments
 Most exist in form of inorganic phosphate
 Land-plants-consumers
Sec 3- Biomes
 What is a biome?
 Very large terrestrial ecosystems that contain number of smaller
but related ecosystems within them, have characteristic climate
and species
 How many different biomes cover the Earth’s land surface?
 10
 Each is defined by unique set of abiotic factors-climate, and
by characteristic set of plants and animals
 Tundra, taiga, temperate forest, northwestern coniferous
forest, temperate woodland and shrubland, tropical rain forest,
tropical dry forest, temperate grassland, tropical savanna, and
desert
 Tundra is cold and treeless
 Covers 1/5 of world’s land surface
 Very little precipitation, short growing seasons, animals include
caribou, musk oxen, snowy owls, arctic foxes, snowshoe hares
 Permafrost
 Northern N America, Asia, Europe
 Taiga- covered with dense evergreen
forests
 Plants are adapted for long and cold winters,
short summers and poor soil
 Animals include moose, bears, wolves and lynxmany hibernate for 6-8 months
 North America, Asia, northern Europe
 Temperate forests-trees loose their leaves,
pronounced seasons, precipitation evenly
distributed, cold winters/warm summers
 Trees include cottonwood, maple
 Animals include deer, foxes, raccoons
 Eastern U.S., most of Europe, China
 Temperate Grasslands- contain grasses, low
rainfall, fertile soil, support herds of mammals,
turned into farmland
 Warm to hot summers/cold winters
 North America, central Europe
 Deserts- receive less than 25 cm of rainfall a year,
cold at night, vegetation is sparse, animals include
foxes, lizards and snakes
 Africa, Middle East, Australia
 Savannas- tropical and subtropical grasslands with
scattered trees and shrubs
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Herbivores-zebras, giraffes, and gazelles
Carnivores-lions, leopards, and cheetahs
Climate-Two seasons- wet and dry
Eastern Africa, southern Brazil
 Tropical Rain forest-tall trees, year round
growing seasons, abundant rainfall, highest
species richness
 Animal life very diverse-birds, monkeys, snakes,
lizards
 Insects very abundant
 Contains 1/5 of world’s known species
 2 football fields may have 300 species
 Southeast Asia, southern India, parts of Central and
South America
 Tropical Dry forest- precipitation is seasonal
rather than year-round
 Generally warm year-round, rich soils
 Tigers, elephants
 Parts of Africa, Mexico, India
 Temperate Woodland and Shrublandsemiarid climate, dominated by shrubs
and open woodlands
 Coyotes, foxes, blacktailed deer
 Hot, dry summers, cool moist winters
 Western coasts of N and S America
 Northwestern Coniferous forest- made up
of variety of conifers, lush vegetation
 Mild temperatures, cool summers with
abundant precipitation during spring, winter,
fall
 Pacific coast of northwestern U.S. and
Canada
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Tundra
Taiga
Savanna
Deciduous Forest
Rainforest
Grasslands
Desert
www.blueplanetbiomes.org/world_biomes.htm
Aquatic Ecosystems
 Determined by primarily the depth, flow, temperature,
and chemistry of the overlying water
 Grouped by abiotic factors that affect them
 Freshwater ecosystems divided into 2 types- flowing
water and standing water ecosystem
 Plankton- tiny, free-floating organisms live in
freshwater and saltwater
 Phytoplankton- unicellular algae supported by
nutrients, form base of food web
 Zooplankton- planktonic animals that feed on
phytoplankton
 Freshwater wetlands- water covering land for at least
part of year
 Bogs, marshes, swamps
 Estuaries
 Estuary occurs where freshwater rivers and streams
flow into the sea
 Ex. Bays, mud flats, salt marshes, Mangrove
swamps
 Very species rich
 Vital to marine animals that are used as food
 Ex. Shrimp, mullet, redfish, anchovies
 Marine Ecosystems
 Divided into photic and aphotic zones
 Ocean divided into zones based on depth, distance
from shore: intertidal zone, coastal ocean, open ocean