Lecture 14

Question 1

What is Biodiversity?

Answer 1

• It is the variability among living organisms from all sources, including diversity within species, between species, and of ecosystems.
  (UN’s formal legal def)
  Canada was the first country to sign on

Question 2

What are the 3 levels of biodiversity?

Answer 2

1. Genetic variation within population and species (genetic variation)
2. Number of species that are found within an ecological community (species variation)
3. Assortment of communities at a landscape scale (community variation)

Question 3

What is Genetic variation?

Answer 3

Each organism has a unique genome (most similar to parents and siblings)
* Variability of individuals is based on pool of
genetic variation within a population, and
the expression of genetic information (phenotypic plasticity)

Question 4

Clonal reproduction

Answer 4

Lower genetic variability
Some species can reproduce
asexually so that offspring are
genetic clones of their parents
* The largest known trembling aspen
covers more than 43 ha, consists of
47,000 stems, and weights more than
6 million kg
Clone-genetic identical offspring
no differential separation to protect them from arising challenges

Question 5

Sexual reproduction

Answer 5

Sexual reproduction has a powerful influence on genetic diversity
* Haploid sex cells from both parents undergo
recombination to create unique diploid
organisms
* High genetic variation is typically observed in
sexually reproducing organisms drives variation
- Biodiversity is higher

Question 6

Low genetic diversity

Answer 6

Genetic diversity allows populations to respond to environmental changes
* Populations with low genetic diversity are at
risk in changing environments
* They are also vulnerable to pests and disease
ex. if 10% of us harbour an immunity to a plague, then humanity is likely to continue
- As environment changes faster, organisms with higher genetic variation have an advantage
ex. Aurora trout have low diversity
- they faced nickle poisoning
- breed in captivity

Question 7

Endemic species and other taxa

Answer 7

Endemic species occur in a restricted area-represent local adaptation
* Remote islands are often rich in endemic
species:
ex. darwin’s finches
e.g. prior to discovery by humans, Hawaiian flora was 98% endemic
* We are trying to understand is there enough of the first level biodiversity in the environment or are they facing extinction
limited genetic diversity

Question 8

The Florida panther

Answer 8

• Pumas are apex predators found in
  North and South America
• They provide an interesting case-study of
  the effects of small endemic populations
• They were once widespread throughout North America (now only on west coast and Florida)
• by late 20th century, there were only 20 to 25 adults in Florida they were at risk of being extirpated
• Genetic diversity was rapidly lost
• Genetic analyses indicated inbreeding
  within this population
  Solution:
  Catch pumas in Texas put them in Florida (8 females)
• Pumas were genetically rescued from the influx of new genes
  -Heterozygosity went up
• average age got younger (more young were able to survive)

Question 9

What is species richness

Answer 9

Number of species in a particular area
- Can focus at diff taxonomic level don’t always have to look at everything
* Richness can be measured at different
scales (within a community, park,
country, etc.)
- Must have knowledge in systematics and taxonomy
- Species must be classified by their Latinized binomial name
- 2 million species named

Question 10

Global species richness (table 12.1)

Answer 10

Number of described and estimated species
varies across taxonomic groups
* In some groups, most species have not yet
been described
* Small tropical arthropods are especially poorly known
- Temperate versus tropical dichotomy:
* About 65% of named species live in the
temperate zone (lots of universities)
*Hidden biodiversity is mostly in Beatles
* About 90% of yet-to-be discovered species live in the tropical rainforest (one biome)
* Science suffers from a temperate-zone bias

Question 11

The modern syntheses

Question 12

Canadian species richness

Answer 12

• In Canada, a large number of species
  have not yet been discovered
• Most of the species yet to be named in Canada are Beatles

Question 13

Species richness decreases with ……

Answer 13

Latitude.

• Most species we don’t know yet are in the tropics

Question 14

Diversity extremes

Answer 14

• Luehea seemannii tree was found to
  have 1100 species of beetles in its canopy,
  14.5% were unknown to science

Question 15

Diversity extremes

Answer 15

• 742 tree species (DBH>10cm) were found
  on a 3 hectare plot in Malaysia with 50% as
  single individuals
• In all of Canada, there
  are ~300 tree species!
• Three times that number in one plot then we have in all of Canada

Question 16

Richness of communities

Answer 16

A landscape with a dynamic mosaic of different communities is richer than a uniform landscape