science term 1 2009
DESCRIPTION
Science Term 1 2009. Miss Simpson. This term we are going to be looking at 2 main topics…. “Eco warriors” “Under the sea” The strands you will be tested on are : investigating life and living earth and beyond. - PowerPoint PPT PresentationTRANSCRIPT
Science Term 1 2009
Miss Simpson
This term we are going to be looking at 2 main topics…
• “Eco warriors”• “Under the sea”
• The strands you will be tested on are :investigating life and living
earth and beyond
• We will also go to Scitech once a week to conduct experiments and see the new displays they have there.
• We will try to organise an excursion where we go to Mettam’s Pool (coral reef) or perhaps even AQUA
But the bad news…• You will have homework!!!
• There will always be things that you need to finish off from class
• You also have a Science homework book that we will use throughout the term.
• If you need some help with your homework or access to a computer after school, I will organise a ‘homework club’ for you.
So lets get into it…
___ __ _______ What is ecology?
• The scientific study of the interactions that determine the distribution and abundance of organisms
• Distribution = where an organism is found
• Abundance = how common an organism is
Questions for Ecologists:
• Why are organisms found where they are?
• Why do some places have more organisms than others?
• Why do the numbers of individuals change over time?
• Before we go any further, lets have a look at the way things are structured here on
Earth…
Levels of Biological Organisation:
• biosphere• ecosystems• communities• populations• organisms• organ systems• organs• tissues• cells• organelles• molecules
BiosphereBiosphere
Ecosystems
Communities
Populations
Organisms
What is the role of Ecology in society?
• To provide impartial information gathered from scientific study that can be used to guide public policy (laws etc)
• It is NOT to make moral judgments on issues and policies
An Example:Otters, oil, and killer whales
• In 1989: the Exxon Valdez ran aground in Prince William Sound, Alaska
The largest oil spill ever in the US
Plants and animals devastated
• One role of ecologists was to document the short term impact on the organisms
• NOT decide whether or how much Exxon should pay
What about the sea otters?
• Its been almost 20 years since the spill and they still haven’t recovered
• Should Exxon pay more -- are they at fault?
Sea otter (Enhydra lutris)
• A small (≈ 25kg) marine mammal
• Relies on fur, not fat, for insulation
• Oil mats fur and reduces insulation
• Historically hunted for fur (nearly driven to extinction in 1800’s)
• They recovered in parts of US, but still protected by law
Ecologists job
• So is Exxon responsible ?
• Ecologists have been studying the sea otters and this is what they found:
— Sea otter populations throughout Alaska began crashing in 1980’s
— Most of these populations were not impacted by the oil spill
Indicates that the current problem with otters is not due to the oil spill…
But what then?
• We need to look at the eating habits of the killer whales…
• Scientists observed killer whales eating otters (which they don’t usually do)
• A single killer whale could eat 2000 otters a yearBut why are they only eating otters now?
What’s going on?
• The killer whales used to eat sea lions & seals
• But now these prey items have become rare
• Why?
Overfishing• Pollock and Salmon – the 2 foods that sea lions &
seals love to eat.
• If there is not enough food for sea lions & seals they will starve
• If there are not enough sea lions & seals, the Killer whales will starve
• As a result: Killer whales started eating sea otters
Food web: before overfishing
Killer whaleHumans
Urchins
Kelp
Sea OtterSea lion &
Seal
Pollock &
Salmon
Urchins Sea otter eating an urchin
Sea lion eating a salmon
A killer whale eating a Sea lion
Food web: after overfishing
Killer whaleHumans
Urchins
Kelp
Sea otter
Sea lion &
Seal
Pollock &
Salmon
• Now it’s time for you to do some work…
ACTIVITIES
• 1. Complete the wordsearch.
• 2. Using the word ECOLOGY, write down as many things as you can that relate to this topic – you can use single words or write down sentences about what you already know.
• 3. Research the definitions for the words you found in your wordsearch.