ECOLOGY AND HUMAN INTERACTIONSWhat happens to the world

now that we are in the picture?

Reminder- Niche

A niche describes ALL of the characteristics that any species needs to survive Examples:

amount of space type of food climate conditions

If humans change any of these in any place, they make a species die off or move, because they have changed its niche

Biodiversity

bio- living diversity- differences

the number of different living things in an area

more biodiversity gives the ecosystem a better chance for overall survival when changes occur

Population Growth

Most populations grow exponentially until they reach their carrying capacity the maximum number of individuals that area

can hold Something limits their growth

this is their limiting factor may be amount of space, food, or number of

predators

Human Population Growth

Human Activities

Many human activities create or change different areas’ limiting factors

*All of these are because of increasing human populations! overconsumption habitat fragmentation invasive species global warming ozone depletion biomagnification

Overconsumption

Humans take more than they need overharvesting of tuna population crash overhunting of bison, wolf overharvesting of shrimp

If too few are left in too large an area, they cannot find mating pairs

Often, products are taken without regard for other items around them

Direct harvesting- picking of only the best or most desired crops, leaving the others behind

Habitat Fragmentation

Breaking up large areas of land so humans can use them

Olympic National Park Example

Introduced/Invasive Species

species introduced to an area where they do not belong THEY HAVE NO NATURAL PREDATORS, so they

are better competitors and take over!

Global Warming

Gases put into the atmosphere trap heat around Earth, making a “blanket” guilty gases:

carbon dioxide water vapor methane

Increase in global temps by 1-2 degrees celcius could make oceans rise by as much as 20

feet!

Global Carbon Dioxide Levels

Ozone Depletion

DIFFERENT FROM GLOBAL WARMING! Certain chemicals in the air act to break

down a layer in our atmosphere that protects us from the sun’s radiation. this makes us cooler BUT increases our risks

for cancers

Biomagnification

(or biological magnification)

Any toxic substance that begins in an ecosystem will get passed up in higher and higher concentrations as it works its way up the food web

The end result…

We have changed the Earth in so many ways that we are causing: species to MOVE

ex. maple trees species to go extinct (no longer in existence

anywhere) ex. dodo bird

6th extinction??? 5 times in Earth’s history there have been

massive die-offs of species. Are we the cause of #6?

Biodiversity Hotspots

Question?

List three positive and three negative things humans have done to the environment