IB Conservation Biology

Ozone layer

• The ozone layer is in the stratosphere and absorbs/blocks UV radiation

• In 1985 data collected on the ozone layer showed a dramatic depletion particularly over Argentina and antarctica 

What was the thinning caused by?

This thinning was caused by the releases of CFCs. In the presence of UV light CFC becomes Cl-

What are CFCs used for?

CFCs used for aerosol,  freezers, refrigerators, and air conditioners.

Why is the ozone largely fixed?

Ozone hole is largely fixed due to finding replacements for CFCs

O3

Chemical formula for ozone

Conservation Biology

Conservation biology is an attempt by scientists and governing bodies to maintain or increase biodiversity

How can humans increase biodiversity?

• Reintroduce species

• Make new habitats for species to live in

Indicator Species

If present, indicates a healthy ecosystem

Restoration

Bringing a habitat back to its former state

Threatened Species

Was plentiful, but now on its way to being an endangered species

Ex: Great white population bounced back once California mad hit an illegal species to fish

Endangered Species

• At risk of becoming extinct

• Titles can be given by nations or the international communities

• Illegal for humans to interact with threatened or endangered species except for research purposes

• Removal of introduced species

• Alien and invasive species tend to be removed in management areas

• All of the above requires both prioritization and funding

Biological reserves

Area that is protected for biodiversity

What are the three features needed to be considered for a reserve to be successful?

Size, edge effect, and corridors

Size

Single large vs. several small

Edge Effect

Area where thing sin the preserve interact with things not in the preserve

• Example cowbirds vs. songbirds

• Percentage composition is integral

• More edge effect in a small nature reserve than a large nature reserve → border takes up more percentage in smaller reserves

Corridors

Connect habitats

What causes extinction?

Change → new competitor or the environment is change and the species is no longer well suited for the environment

Local Extinction

Extinction in an ecosystem but not extinction globally

• Ex: no grizzly bears in California

What is a keystone species?

A species that other organisms in an ecosystem depends on, disproportional impact on the other species in an ecosystem

Marsupials

• Does most development in parents’ pouch

• North America only has opposums

  • Competition → extinction

• Marsupials in Australia

  • Placental mammals could not get to Australia

What are the three ways to calculate a fishes age?

Ear bones, Fish scales, and hubs fish heads

Ear bones

Every year fish put a new layer of bone on their ear bones → you can count the rings

Fish scales

Scales have a ring where more material is added each year → you can count the rings

Hubbs fish heads

• Hubbs is the research arm of seaworld

• Hubbs breeds white seabass

• Microchip put in head

• You can cut out the head and send it to hubbs

Maximum sustainable yield

• Maximum number of individuals from one species that humans can collect without damaging the population

  • Taking as many individuals as new individuals can be born

• Not widely practiced

Maine lobster

Minimum and maximum size → best genes and most fecundity (reproductive rate)

Great white sharks

Maximum sustainable yield for great white sharks is 0 because they reproduce so slowly

How do humans use coal?

Coal used for electricity → rotate magnetic fields we will create an electrical field (heat from burning coal)

How do humans use trees?

Trees used for wood → buildings and infrastructure → deforestation, erosion → algae blooms and dead-zones

How do humans use fish stocks?

• We fish them to eat

• Fish stocks: amount of fish available (commercially viable species) → releases Hg into the atmosphere which gets into organisms → when you eat enough of the organisms you get a neurological disorder; decreased biodiversity

  • Also depends on how you catch the fish 

International Council for Exploration of the Sea (ICES)

Recommends catch levels for fish stocks

Bycatch

Organisms caught and killed accidentally

Purse Seine

Used to catch large amounts of fish

Rod and reel

Has the lowest amount of bycatch because they can release the unwanted fish and they often survive → often used for niche fishing

Gill Net

Monofilament net, extremely high bycatch → gill net fishing is illegal in California

Long line

• Long cord (1-3 miles long), each secondary line has a baited hook, medium amount of bycatch

• Problem comes with length of line → something may be stuck on the hook for 10 hours and die on the hook

Otter trawl

Tunnel shaped that catches organisms on the substrate which is moving faster than the fish can swim, tend to haul al to of the fish in before they can die → disturbance of habitat

How do we determine fish population?

Tagging to determine what type of fish is under the water and in what quantity

Why were fish stock historic laws enforced?

Due to overfishing

• For example in 2007 it was discovered the Atlantic Cod levels were 75% lower than their historic levels

NOAA

• Deals with climate, oceanography, and marine biology

• In 2021 NOAA announced that regulations were working and fish stocks were improving