1. if you were asked to manage this site for species diversity, what would you aim to do? how would...

• 1. If you were asked to manage this site for species diversity, what would you aim to do? How would you do it?

• Species richness- the number of species in a given area.

• Species evenness- the measure of whether a particular ecosystem is numerically dominated by one species or are all represented by similar numbers of individuals.

Measuring Biodiversity

Biodiversity• Diversity Increasers Diversity Decreasers – Diverse habitats– Disturbance in the habitat (fires, storms, etc.)– Environmental conditions with low variation– Environmental stress– Evolution– Extreme amounts of disturbance– Extreme environments– Extreme limitations in the supply of a fundamental resource– Geographic isolation– Introduction of species from other areas– Middle states of succession (habitat regrowth)– Trophic levels with high diversity

Biodiversity• Diversity Increasers Diversity Decreasers

• Diverse habitats• Disturbance in the

habitat (fires, storms, etc.)

• Environmental conditions with low variation

• Evolution• Middle states of

succession• Trophic levels with high

diversity

• Environmental stress• Extreme amounts of

disturbance• Extreme environments• Extreme limitations in

the supply of a fundamental resource

• Geographic isolation• Introduction of species

from other areas

As far as we can tell, we are the only species that can value its diversity.

• Should we take care of it?• How will people later judge our

generation if we do not attempt to preserve a minimum of diversity, especially because we know perfectly well how to accomplish this?

• Too much interruption might have unpredicted but severe consequences for human lives and society.

What creates all this biodiversity?

•EVOLUTION!the process by which different kinds of living organisms have developed and diversified from earlier forms during the history of the earth.

Evolution is the mechanism underlying biodiversity

• Evolution- a change in the genetic composition of a population over time.

Fossils present but rare

Evolution and expansion of life

Fossils become abundant

Plants invade the land

Age of reptiles

Age of mammals

Insects and amphibians invade the land

Modern humans (Homo sapiens) appear about 2 seconds before midnight

Recorded human history begins 1/4 second before midnight

Origin of life (3.6–3.8 billion years ago)

Cane Toad – Team Think3. Distinguish between , natural selection, artificial selection and genetic engineering.- Which of these took place in this movie? why?- Now, how would scientists use genetic engineering

to “solve” the cane grub problem?

Evolution• Evolution by artificial

selection- when humans determine which individuals breed.

• Evolution by natural selection- the environment determines which individuals are most likely to survive and reproduce.

• Evolution by genetic engineering the deliberate modification of the characteristics of an organism by manipulating its genetic material.

Some… of the GMOs• Honey - produced from GM crops. • Cotton - Resistant to certain

pesticides – • Rice - Genetically modified to

contain high amounts of Vitamin A. • Soybean - Genetically modified to

be resistant to herbicides – • Sugar cane - Made resistant to

certain pesticides. • Tomatoes - Made for a longer shelf

life • Corn - Resistant to certain pesticides • Sweet corn - genetically modified to

produces its own insecticide. • Canola – • Potatoes - -

Flax - An herbicide-resistant GM flax was introduced in 2001, but was soon taken off the market because European importers refused to buy it.Papaya - The first virus resistant papayas were commercially grown in Hawaii in 1999. Cotton seed oil – Meat - Meat and dairy products usually come from animals that have eaten GM feed.Peas - Genetically modified (GM) peas created immune responses in mice, suggesting that they may also create serious allergic reactions in people. .Vegetable Oil - Most generic vegetable oils and margarines used in restaurants and in processed foods in North America Dairy Products - About 22 percent of cows in the U.S. are injected with recombinant (genetically modified) bovine growth hormone (rbGH).Vitamins -

• Livestock genetically altered to give maximum output at minimum cost to farmers (high milk production or high meat output, sheep optimum wool growth, pigs could be altered to have large amounts of meat with a minimum of fat)

* Crops genetically altered for resistance to drought, frost, pests, disease, and herbicides

Chec

k in

Interpret the graph

As land size increases

the diversity in

species increases

Interpret the graph

Interpret the graph

The Plot Thickens! Using the data and knowledge from the last few graphs, explain the

relationship between # of species and Sunda Islands and New Guinea

Island Biogeography

Unique characteristics of islands

• Isolation

• Disturbances can be catastrophic

• Less genetic diversity (than mainland settings)

Deforestation

Central Park NYC

Mountain Tops

Suburbs

Farming / Agriculture

Farming /

Agriculture

* More species on bigger islands * Fewer species

on more isolated islands

Theory of Island Diverstiy The number of species found on an undisturbed island is determined by immigration and extinction. This can lead to evolution. Immigration and emigration are affected by the distance of an island from a source of colonists. Usually this source is the mainland. As well as size of the island Islands that are more isolated are less likely.

Large Close Small Close

Large Far

Small Far

Share data with 2 – 3 other teams and average out

YOU!

1 meter away 1 meter away

1.5 meter away

1.5 meter away

Exit Card

• You are a part of a forestry science team appointed by the government to determine what kind of forest islands are the most desirable in order to save native fauna and flora, which may migrate between habitat lands.

• Describe the size of your habitat land, its distance from the source population and supporting reasoning as to your decision.

Island Biogeography = immigration – extinction

Source: MacArthur and Wilson. The Theory of Island Biogeography

As the number of species on an island increases, the rate of colonization will decline because available ecological niches become fewer

As the number of species on an island increases, the rate of extinction will increase because species compete for resources

Island Biogeography = immigration – extinction

Species Equilibrium

The number of species on an island represents a balance between colonization and extinction

Source: MacArthur and Wilson. The Theory of Island Biogeography

How does this relate to landuse/landcover change?

Species Extinctions

Source: World Conservation Monitoring Centre, "Global Biodiversity" Chapman & Hall, London, 1992)

Source: Bolger et al., 1997. Response of rodents to habitat fragmentation in coastal southern California. Ecological Applications, 7(2): 552-563. (note: trend line added to rodents vs shrub size figure)

Conservation initiatives

Evolution by Random Processes

• Mutation- occur randomly and can add to the genetic variation of a population.

• Genetic drift- change in the genetic composition of a population over time as a result of random mating.

• Bottleneck effect- a reduction in the genetic diversity of a population caused by a reduction in its size.

• Founder effect- a change in a population descended from a small number of colonizing individuals.

Evolution shapes ecological niches and determines species distributions

• Range of tolerance- all species have an optimal environment in which it performs well. The limit to the abiotic conditions they can tolerate is known as the range of tolerance.

• Fundamental niche- the ideal conditions for a species.

Niches• Realized niche- the range of abiotic and

biotic conditions under which a species lives. This determines the species distribution, or areas of the world where it lives.

• Niche generalist- species that live under a wide range of conditions.

• Niche specialist- species that live only in specific habitats.