1. Chapter 8: Biological Diversity and Biological Invasions

2. Overview What is Biological Diversity? Biological Diversity Basics
Biological Evolution
Competitive and Ecological Niches
Symbiosis
Predation and Parasitism
How Geography and Geology Affect Biodiversity
Invasions, Invasive Species and Island Biogeography

3. What is Biological Diversity
Bio diversity refers to the variety of life forms in an area.
Expressed 2 ways
Number of species in an area
Number of genetic types in an area

4. Why Do People Value Nature?
Eight Reasons
Utilitarian
Public service
Moral
Theological
Aesthetics
Recreational
Spiritual
Creative

5. Biological Diversity Basics
Genetic Diversity
Total number of genetic characteristics of a specific species, subspecies, or group of species
Habitat Diversity
The different kinds of habitats in a given unit area
Species Diversity
Species richness - total number of species
Species evenness - relative abundance of species
Species dominance - the most abundant species

6. Species Diversity
Counting the number of species is not enough to describe biological diversity
Left = 10 species; 100 individuals, 87 elephants, 9 species with 2 individuals each
Right = 10 species; 100 individuals, 10 individuals each species
Which has greater species richness? Species evenness?

7. Number of Species on Earth
1.5 million species have been identified
Estimated that almost 3 million different species currently exist
All living things categorized into taxa
Kingdom
Phylum
Class
Order
Family
Genus
Species

9. Biological Evolution How did biological diversity come about?
Too amazing to have come about by chance
Many believed that it must have been created by God
“everything in the world is marvelously ordered by divine providence and wisdom for the safety and protection of us all” -Cicero

10. Biological Evolution Charles Darwin Biological Evolution Ninth century
Explanation of diversity known as biological evolution
Biological Evolution
Change in inherited characteristics of a population from generation to generation

11. Biological Evolution New species arise as a result of:
Competition for resources
Difference among individuals in their adaptations to environmental conditions
Four processes lead to evolution
Mutation
Natural selection
Migration
Genetic drift

12. Mutation Genes are inherited from one generation to the next
Contained in the chromosomes of each cell
Genes made up of DNA
DNA made up bases A,C,G,T
How these letters are combined determines the “message” interpreted by a cell

13. Mutation When cells divide
DNA is reproduced
Each new cell gets a copy
Mutation - when an error occurs in the reproduction of DNA as it gets passed to new cells
Possible causes: radiation or a viruses

14. Mutation In some cases offspring with a mutation cannot survive
In some cases a mutation simply adds to genetic variability in the species
In some cases mutation changes the offspring drastically and a new species is created

16. 5 big factors that decrease biodiversity - HIPPO
H = Habitat Destruction
I = Introduced Species
P = Pollution
P = Population Growth
O = Over-consumption

17. Natural Selection
Some individuals may be better suited to the environment than others
Those better able to survive and reproduce leave more offspring
Their descendants form a larger proportion of the next generation
The accumulation of changes may lead to reproductive isolation
Resulting in a new species

18. Natural Selection Four primary characteristics Genetic variability
Environmental variability
Differential reproduction that varied with the environment
Influence of the environment on survival and reproduction

19. Migration and Geographic Isolation
Two populations become geographically isolated for a long time
Differences accumulates so that they no longer reproduce
Two new species have formed
Migration important evolutionary process (Adaptive Radiation)
Ex: Hawaii honey creeper and Darwin’s finches

21. Genetic Drift Genetic drift Founder effect
Changes in frequency of a gene in a population simply by chance
Founder effect
Small number of individuals are isolated from larger population
Less genetic variation than original population
Characteristics present are affected by chance
Individuals may NOT be better adapted

22. Interaction between Species
Competition
The outcome is negative for both groups
Symbiosis
Benefits both participants
Predation and parasitism
The outcome benefits one and is detrimental to the other.

23. Competitive Exclusion Principle
Two species that have exactly the same requirements cannot coexist in exactly the same habitat.
Ex- British Red Squirrel and American Grey Squirrel

24. Niches: How Species Coexist
Ecological Niche Concept
Explains how so many species can coexists
Example: Flour beetles (Tribolium)
Specific # of beetles of two species placed in flour
Containers maintained at various temp and moisture levels
Periodically beetles counted
One species always wins but which one depends on conditions

27. Niches: How Species Coexist
All flour beetles have the same ecological functional niche
Same “profession” – eating flour
Different Flour beetles can live in different habitats

28. Measuring Niches Describe the niche Measured Niche
the set of all environmental conditions under which a species can persist and carry out its life functions
Measured Niche
Fundamental niche
Realized niche
Ex- flatworms in streams

29. Fundamental temperature niche
The occurrence of freshwater flatworms in cold water streams in Great Britain. When A and B occur alone niche is larger than where they occur together.
Realized temperature niche

30. Symbiosis Describes a relationship between two organisms
beneficial to both
enhances each organism’s chance of persisting
Each partner called a symbiont
Ex- reindeer and gut bacteria
Food for reindeer
Home for bacteria

31. Predation and Parasitism
Relationship is beneficial for predator or parasite and negative for prey or host
Predation
One organism (predator) feeds on other live organisms (prey)
Parasitism
One organism (the parasite) lives on, in, or within another (the host)

32. How Geology and Geography Affect Biologic Diversity
Species are not uniformly distributed over the earth’s surface
They are not uniformly distributed locally, either
Species change with soil type and topography:
slope, aspect (the direction the slope faces), elevation, and nearness to a drainage basin

33. Interrelationships among climate, geology , soil, vegetation and animals.

35. Biotic Provinces
In 1876 Wallace suggested that the world could be divided into six biogeographic regions
Referred to as realms
Neartic, Neotropical, Palaeartic, Ethiopian, Oriental, and Australian

37. Biotic Provinces
In each major biogeographic area certain families of animals are dominant and fill ecological niches
For example large herbivores
North America - bison and pronghorn
South America - capybara
Australia - kangaroo
Africa - giraffes and antelope

38. Biotic Provinces
Wallace’s realms still valid and extend to all life forms
A biotic province is a region inhabited by a characteristic set of taxa, bounded by barriers that prevent emigration and immigration.

39. Biotic Provinces W/in a realm
Species more likely to be related
Evolved and adapted in the same place for a long time
When a species introduced may be unrelated or distantly related to native species.
Ecological and evolutionary adjustments are yet to take place.
Introduced species may be superior competitor

40. Biomes
Similar environments provide similar opportunities and similar constraints
Leads to evolution of organisms similar in form and function
Rule of climatic similarity

41. Biotic Province vs. Biome
A biotic province is based on who is related to whom
An evolutionary unit
A biome is based on niches and habitat
If we know the climate we can make predictions about the biome

43. Saguaro from North America
Example of Convergent Evolution- given sufficient time and similar climates species similar in shape and form will tend to occur
Joshua Tree
Saguaro from North America
Euphorbia of East Africa

44. Ostrich from Africa
Rhea from South America
Emu from Australia
Divergent evolution - population is divided and each evolves separately

45. Invasions, Invasive Species and Island Biogeography
Fewer species than continents
Two new sources of species is migration and evolution
Smaller the island the fewer the species
The farther away from a continent the fewer the species

47. Island Biogeography Small islands tend to have fewer habitat types
A small population easily wiped out by a storm, flood, catastrophe or disturbance
The smaller the population the greater the risk of extinction
The farther an island is from the mainland the harder it is to reach

48. Island Biogeography
Islands tend to maintain consistent number of species over time.
Result of the rate at which species added
Minus rate at which they become extinct
Concept applies to ecological islands
A comparatively small habitat separated from a major habitat of some kind.

49. Biogeography and People
Biogeography affects biological diversity
Changes in biodiversity affect people and resources
Effects extend from individuals to civilizations

50. Biogeography and People
People alter biodiversity by
Direct hunting
Directly disturbing habitats
Introducing exotic species into new habitats
Introductions of exotics have mixed results
Food sources, landscaping, pets
Disastrous ecological consequences