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.