ecology and earth...
TRANSCRIPT
Ecology and
Earth ScienceChapters 1-5
Learning Goals Quiz #12
Describe and identify the levels of organization in Ecology
Know the difference between abiotic and biotic factors
Recognize the relationships between producers and consumers, including feeding and habitat relationships
Describe the flow of energy in trophic levels using food webs and/or pyramids
Give methods and reasons for the recycling of nutrients in the Biosphere
Quiz #13
You will be able to define succession and why it’s good for an ecosystem
You will be able to describe and read a population graph for all species, including humans
You will be able to explain what factors affect populations
You will be able to describe the reasons and causes for vanishing and extinct species
You will be able to explain humanity’s efforts toward conservation and preserving species
Ecology A major portion of biology is the science of
ecology.
Ecology is the study of interactions that take
place between organisms and their environment
How do organisms rely on each other to survive?
How do things like the weather and land formations
affect organisms?
How do nutrients cycle throughout the earth so that
they don’t go to waste?
Abiotic Factors Anything in an environment that is non-living is called
an abiotic factor
Temperature
Weather patterns
Presence of light
Soil composition
Abiotic factors can be both helpful and detrimental to
an organism, even to the point where the presence of
an abiotic factor determines whether or not a species
survives.
Ex. What is the impact on bumblebees if a late frost
occurs?
Biotic Factors Any living organism in an environment, whether
or not it directly affects an organism, is a biotic
factor.
All organisms require at least one other organism
Food: Animals eat other organisms (plant or
animal)
Shelter: Birds use the heights of trees to protect
against ground predators
Reproduction: Flowers rely on insects to pollinate
and reproduce
Protection: Remoras, tiny sucker-fish, live attached
to larger marine animals for defense.
Levels of Organization Biology and ecology are described in different
levels of organization.
These levels are based on what organisms are
present and what interactions occur.
Levels of organization help scientists identify
different interactions and what the
consequences of these interactions are
Atom Molecule Organelle Cell Tissue
Organ Organ System…
Levels of Organization Level #1: Organism
Every individual is it’s own level of organization
Level #2: Population
A population is a group of organisms of the same
species, which can interbreed and live in the same
area at the same time.
Members of the same population work together for
protection
Members also compete for food, mates, and
places to live
Levels of Organization
Level #3: Community
A community is a group of more than one
population interacting in the same area at the
same time.
The individual populations in the community may
directly or indirectly interact with each other, but
some interaction does occur.
The populations may compete with each other
(sharks and dolphins), help each other (clownfish
and anemones), or have no affect on each other.
Levels of Organization
Level #4: Ecosystems
Ecosystems are groups of communities as well as
the abiotic factors in the same area at the same
time.
Ecosystems can be both terrestrial and aquatic
Forests, meadows, a garden, a lake, deep ocean,
shallow ocean
70% of the earth’s surface are salt-water
ecosystems
Levels of Organization Level #5: Biomes
Biomes are groups of ecosystems that share similar average temperatures and rainfall levels
In general, there are 14 recognized terrestrial biomes, 12 freshwater biomes, and 5 marine biomes
○ Desert, temperate rainforest, tundra, upland river, etc.
Level #6: The Biosphere
The portion of Earth in which life exists, including the land, water, and air or atmosphere
Ranges from the bottom of the ocean to the top of the sky
Does not include below the surface of the earth, so it’s not just another word for “the earth”
If the earth were the size of an apple, the biosphere would be around the size of the peel.
Habitats and Niches
A habitat is where an organism will live throughout its
life.
Habitats can change, move, or even disappear.
A habitat can be as big as a desert or as small as a
tree stump
If a habitat is like an organism’s address, a niche is like
an organism’s profession
A niche is a part of how an organism lives that allows it
to avoid competition
If two organisms live in the exact same habitat but live
different types of lives, they don’t compete
Habitats and Niches
Example of Niche’s: The Horned Owl and Red Fox
Both owls and foxes live in low lying forests. Both eat
small rodents off the forest floor. But the foxes feed at
day and the owls feed at night, so they don’t compete
with each other.
Symbiosis
Some organisms are so dependent on interacting with other species that they are in life-long coordination with those species. This is called symbiosis.
Mutualism: Two species benefitting from each other
Butterflies and Flowers
Commensalism: One specie benefits, the other is unaffected
Whales and barnacles
Parasitism: One specie benefits, the other is harmed
Ticks and Dogs
Autotrophs
Autotrophs are also known as producers
In the ecological world, you are either a producer (you produce your own food) or a consumer (you collect food)
Sunlight is the main energy source for life on earth
Plants and some bacteria are able to absorb sunlight.
The sunlight is used by these organisms to produce food.
Of all the sun’s energy that reaches the earth, less than 3% is used by living things
Consumers
If you’re not a producer, you’re a consumer.
Consumers must eat or absorb food for energy
There are five types of consumers
1) Herbivores: eat only plants
○ Cows, deer, caterpillars
2) Carnivores: eat other animals
○ Snakes, dogs, owls
3) Omnivores: eat both plants and animals
○ Humans, bears, crows
Consumers, cont.
4) Scavengers: feed on decaying
matter (plant or animal), which is called
detritus
Mites, earthworms, snails, crabs.
5) Decomposers: Break down organic
matter, then devour the broken down
nutrients
Bacteria, mushrooms
Flow of Matter and Energy Energy flows through an ecosystem in one
direction
From the sun to autotrophs (producers) to
heterotrophs (consumers)
Energy never goes from consumers to producers
Food Chains—show the flow of energy from
organism to organism
Food chains typically show 3-4 organisms only
Food webs—show all energy transfers in an
ecosystem
Most ecosystems are represented by food webs
Trophic Levels Trophic Levels—each step in a food chain or
food web is called a trophic level 1st level—producers
2nd, 3rd, 4th levels—consumers. (By the time you get to a 5th level, there’s almost never
enough energy left.)
The second level is almost always herbivores
The highest level is the top carnivore/omnivore of an ecosystem
A food chain typically takes you through all four trophic levels once, but…
Only about 10% of the energy available within one trophic level is transferred to organisms at the next trophic level.
Cycles of Matter
Recycling in the biosphere
Energy is a one-way flow, but matter can be
cycled and recycled over and over again.
The sun provides energy, so the sun is a
constant source. But we have a finite source of
matter on Earth. Therefore, we need to recycle
it
Matter can pass from organism to organism,
from the earth to organisms, or from organisms
to the earth.
The Carbon Cycle Carbon is the key ingredient to earth. It is found in
all living organisms, as well as the air, rocks, water, etc.
There are four different kinds of processes involved in the carbon cycle
#1: Biological Photosynthesis, respiration, decomposition
#2: Geochemical Release of CO2 by volcanoes, geysers
#3: Biogeochemical Conversion of organisms into coal and petroleum
(fossil fuels) by the pressure of the earth over time
#4: Human Activity Mining, burning fossil fuels, deforestation
The Nitrogen Cycle
Nitrogen gas makes up 78% of our atmosphere
Nitrogen is essential for making amino acids
(amine=nitrogen)
Nitrogen, in the form of nitrate (NO-), is essential
for plant growth.
Bacteria also use nitrogen in the soil by converting
nitrogen into ammonia, NH4
The Phosphorus Cycle
Phosphorus is not common in our atmosphere,
but is of great biological importance
Phosphorus does not enter the atmosphere. It is
found in soil minerals, rocks and ocean sediments
Phosphorus is an important part of RNA and DNA
Extra Credit for Quiz 12
From 1932-1968 the chemical factory in Minamata,
Japan released wastewater into the Minamata
Bay. The waste contained a dangerously high level
of methylmercury which was absorbed by shellfish
in the bay. Fish in the bay would feed on the
shellfish, then humans would feed on the fish.
Methylmercury is toxic to all animal species, but
which species (shellfish, fish, or humans) was most
affected by the toxin? Explain your answer in 1-2
sentences.
Ecological Succession
When a disaster occurs on an ecosystem, succession is
the process of recovery.
Disasters aren’t always bad. In general, they clean an
ecosystem and allow new organisms to begin growth.
The first event is the disturbance. This may be a storm, a
tree falling, a volcanic eruption, etc.
Next comes the primary species, the first plant (or
autotroph in general) that is able to survive in an area.
Finally comes secondary succession. Species that can
feed on the primary species move in. Then species that
can feed on the secondary species move in, etc…
ADD PIC HERE
Populations
Based on fossil records, what percent of the total number of organisms that have ever existed on the planet are currently alive today?
.8%. The rest have all gone extinct
Based on fossil records, how many mass extinctions have occurred throughout history?
6
A mass extinction is when more than 50% of species on the planet die within a short period (say 20 million years)
Extinction Events
As best as we can tell, earth has seen six major
extinctions
We learn this by comparing the number of fossils found
at depths all around the world and finding levels where
many fossils disappear and new fossils emerge.
Many incidents contribute toward an extinction event
Volcanic eruptions
Meteors
Massive climate shifts
Diseases
Mutations that lead to new species (example: mammoth to elephant)
Biologists study these to find patterns in tracking populations on Earth today
Extinction eventsExtinction Name Time Period Organisms Lost
Cambrian/Ordovincian 488 Million YA Ancient Relatives of snails
and clams
Ordovincian/Silurian 450 MYA Ancient Relatives of coral,
starfish, octopi
Late Devonian 360 MYA Nearly all marine plant and
animal life
Permian/Triassic (The
Great Dying—90%)
251 MYA Flowering plants and giant
insects (crocodiles survived)
Triassic/Jurassic 205 MYA Stegosaurs, Brachiosaurs,
Archaeopteryx, Apatosaur
Cretaceous 65 MYA T-Rex, Pterodactyls, Raptors
Population growth model
While studying population growth in different
species we’ve noticed an interesting trend:
They’re all the same.
All populations follow a 5-step process toward
survival. This can be shown on population graphs.
The key point for a population is where to find
their carrying capacity.
The carrying capacity is the maximum number of
organisms an environment can support.
If your population goes higher than the carrying
capacity, not everyone can survive.
The Population Graph A) A species
begins to
grow. Only a
few starting
members are
reproducing,
so the overall
growth is slow
but climbing
The Population Graph
B) Rapid
Growth
occurs.
Multitudes of
new babies
have grown
and are able
to reproduce.
The
population
growth is
increasing
rapidly
The Population Graph
C) Carrying
Capacity is
reached. As
organisms are
added to the
population,
the food,
shelter and
competition is
too harsh. The
population
begins to die
off.
The Population Graph
D) The stress
of over-
population
takes over.
Lack of
resources
causes
massive
death from
disease,
predators,
malnutrition,
etc.
The Population Graph
E) Stabilization.
Population will
hover at the
carrying
capacity and
fluctuations
will become
less drastic
and extreme.
Population Growth Factors There are basically two ways to grow a population to its
carrying capacity.
R-selection (High rates of birth):
Organisms have a short lifespan, so they reproduce early
and in great numbers.
Almost no parental care occurs. Only the strong survive.
K-selection (Maintain carrying capacity):
Organisms live long lives and birth small litters multiple
different times.
Lots of parental care for offspring means even though
fewer offspring are born, they have a better chance of
survival
Population Growth Factors What factors affect population sizes?
Density-Dependent factors are factors that get
more dangerous with larger populations
Disease: is it easier to catch a cold in subway or on a
deserted island?
Predators: larger groups are easier to find
Food: larger populations require more food.
Density-Independent factors are factors that will
harm a population regardless of its size.
Natural Disasters: tornados don’t target big cities.
Pollution: smog can suffocate one bird just as easily as
10,000 birds.
Human Population Growth So far, the population graph accurately represents
every species studied on the planet—except humans.
Why?
Humans, relatively speaking, are slow reproducers.
The average number of babies born per human mother
on our planet is 2.1
Gestation (time in the womb) is long (nine months)
The typical litter size is 1.
Imagine if humans reproduced like rabbits (100-800 new
babies per year) or insects (a new baby every 12 hours)
Still, our graph looks obviously different from the
previous graph studied…
Declining Populations If a species maintains a carrying capacity, the
species will live in relative harmony.
Biologists are tracking thousands of species and noticing many are continuing to drop, and not showing any sign of stopping.
Animals showing signs of decline can be designated as “threatened” or “endangered” by the government.
Endangered isn’t about small populations. It’s about the continued decrease of a population and ability to rebound.
World population of Bison: 30,000Not in danger
World population of African Lion: 46,000Endangered
Vanishing SpeciesExtinct Dinosaurs, Bali Tiger, Passenger
Pigeon
Extinct in the Wild Seychelles Giant Tortoise, Red-tailed
Black Shark
Critically Endangered Mountain Gorilla, Iberian Lynx,
Florida Panther, Pink-Head Duck
Endangered Blue Whale, Snow Leopard, African
Elephant
Vulnerable Shrews, Skunks, Manatees, Albatross
Near Threatened Western Rattlesnake, Tiger Shark,
Narwhal
Least Concerned Humans, Cows, Trout, Seagulls
Conservation
We are limited on resources. Whatever matter exists
on our planet is all we’ll ever have.
Conservation biology is a new field of science. It
focuses on ensuring diversity of species on our
planet, one way or another.
It also deals with ethical questions of diversity,
conservation tactics, human involvement, and
extinction
In short, conservation scientists believe that life and
diversity provides value.
Current Conservation Issues Habitat Loss
Organisms that rely on particular habitats may find themselves homeless due to mudslides, volcanic eruptions, deforestation
Habitat Fragmentation
Habitat fragmentation is when one wilderness area is suddenly separated from another.
Smaller areas mean a species is more susceptible to risks like disease, fire, famine, etc.
Pollution
Pollution is any environmental change that negatively affects the organisms within the environment
Exotic Species Has a species been introduced to an area that it isn’t
native to? Is it destroying the native species?
Alien Species
Alien species are species that thrive in an area they do
not belong to
The dandelion is from England, and was never found in
America until brought over by the Pilgrims
When ships sailing from Japan emptied their ballast water
into Coos Bay, Oregon, they emptied zebra mussels as
well.
Name an infamous alien species in Clark County,
Washington?
Blackberries, Bullfrogs
Overexploitation
Too much of something can be a bad thing if you don’t
give it a chance to recover
Illegal trade of exotic pets
Clear-cutting
Over-fishing
In the pacific northwest, herring had been overfished 20 years
ago
The lack of herring meant sea otters died out
Since orcas fed on sea otters, their populations died out too
Meanwhile, sea urchins, the food of otters, began to thrive
Sea urchins, who feed on kelp, decimated the kelp
populations
Solutions Habitat Preservation State/National Parks usually act as safe havens for
species
Biologists attempt to repair damaged habitats, such as swamplands.
Habitat corridors Corridors are literal pathways or access roads for
animals only that help connect separated habitats
Reintroduction Programs
Training species in captivity to be released back into the wild (has been incredibly successful)
Captivity
Worst case scenario, put the animals in captivity and maintain the few living species until solutions can be found.
Medicinal Value
Only in the past 65 years have laboratories been used
to “build” medicines. Prior to this, medicines were
always taken from natural specimens
Peniccilum commune (F)
Penicillin, an antibacterial medicine.
Cephaelus ipecacuanha (Pl)
Ipecac, a vomit inducer
Erythroxylum coca (Pl)
An old anesthetic known as “cocaine.”
Limulus polyphemus (A)
Horseshoe crab blood, a bacterial disinfectant for pacemakers
Estimates are that 328 drugs have yet to be found
Agricultural Value
Anyone who has ever eaten a fruit, vegetable,
grain, dairy or meat product knows the benefits of
agricultural conservation
We can experiment with plant genes far more
than any other organism, which helps with
research needs
It also means that should a problem arise with
one crop, entire economies and populations can
suffer
Mites and bees
Consumptive Use
Consumptive use refers to products we
harvest/build/transform from natural resources
Skins
Fibers
Rubber
Lumber
Pollinators
As long as the organism is alive and thriving, we
can obtain resources from it as well.
Other, indirect value uses
Organisms aid humans in ways that are not always
monetary or economic
Waste disposal
Water storage and the “sponge affect”
Where would rainwater go without plants to absorb it?
The “umbrella affect”
Climate regulation
Tourism
Human Impacts
Humans are organisms in this world too. But we
have greater power than almost any other
organism the world has ever known
We have the right to survive and be happy, like
any other organism
At how much expense though?
There’s a great outcry in the past 30 years to
make sure the human “footprint” is exactly the
right size and does not trample on any other
organism
Extra Credit for Quiz 13
Welwitschia plants grow in
the Namib desert, near the African coast on the
Atlantic ocean. Only 1 cm
of rain falls each year, yet
each plant can survive for
1000’s of years and grows
as tall as a human. Explain
how.