1. All we have yet discovered is but a trifle in comparison with what lies hid in the great treasury of nature. Antoine Van Leeuwenhoek

2. Biodiversity and Evolution

3. Case Study: Why Should We Protect Sharks?
More than 400 known species.
6 deaths/yr.
79-97 million sharks killed every year:
-Fins, organs, meat, hides, fear, by-catch
32% shark species threatened with extinction.
Reasons for protection: cancer resistant,
keystone species.

5. Importance of Biodiversity
Biodiversity: the variety of Earth’s species, their genes, the ecosystems where they live, and the sustaining ecosystem processes (nutrient cycling, energy flow).
Vital to sustaining life on earth (supplies us with food, wood, fiber, energy, and medicine).

7. Components of Biodiversity (cont’d)
Functional diversity: bio/chemical processes needed for survival of species & communities.
-energy flow & matter recycling.
Ecosystem diversity: variety of terrestrial and aquatic ecosystems.
-storehouse of genetic, species diversity.

8. Components of Biodiversity
Species diversity:
Est. 8 million to 100 million species.
1.9 million identified.
-insects make up most of known species.
-unidentified are mostly in rain forests and oceans.
Genetic diversity: variety of genetic material within a population.
-enables life to adapt to environmental changes.

9. FYI: Why You Should Love Insects
Bad rep: compete for food, spread disease, bite and sting, invade lawns.
Natural capital:
pollination (allows flowering plants reproduce sexually).
free pest control: insects eat other insects.

10. E.O. Wilson: Biodiversity
Loved bugs as a kid.
Specialized in ants.
Widened scope to
earth’s biodiversity.
Theory of island
biogeography.
First to use “biodiversity” in a scientific paper.

11. Evolution of Species
Biological evolution: change in the genetic makeup of a species over generations.
Theory of evolution: organisms with adaptive traits have an advantage over others.
Alfred Russell Wallace
Charles Darwin:
-studied beak shape in Galapagos finches.
-published On the Origin of Species by Means of Natural Selection.

12. Natural Selection
Individuals with advantageous traits are more likely to survive & transmit traits to succeeding generations.

13. Steps of Selection Genetic variability exists in a population.
-mutations (random changes to DNA) are source of variation.
-mutations within gametes are inheritable.
Environmental factors favor survival of individuals with adaptive trait over others.
Adaptive trait may lead to differential reproduction, which enables individuals with adaptation to produce more offspring.

15. Natural Selection and the Six Kingdoms/Tree of Life

16. The Geologic Time Scale

17. Natural Selection & Genetic Resistance
Ability of members of a population to resist a chemical designed to kill it.

18. Evidence of Natural Selection
Fossil record: entire collection of preserved species.
-represents ≈ 1% of all species on Earth.
Homologous structures:
-similar structures in dissimilar species.
DNA analysis

19. Limitations to Natural Selection
Genetic change must precede change in the environmental conditions.
Reproductive capacity:
-Species that reproduce rapidly and in large numbers are better able to adapt.

20. Common Myths about Evolution through Natural Selection
“Survival of the fittest” is not “survival of the strongest” .
(Fittest is in terms of leaving behind the most offspring )
Organisms do not develop traits out of need or want.
No grand plan of nature for perfect adaptation (evolution is not “goal oriented).

21. Case Study: How Did Humans Become Such a Powerful Species?
Three human adaptations:
Strong opposable thumbs
Walk upright
Complex brain: allows for weapon
development, creation of protective devices, and technologies that extend our senses.

22. 4-3 Geology and Natural Selection
Tectonic plates affect evolution and the location of life on earth.
-change the location of continents & oceans.
-influences climate & distribution of species.
-species became geographically isolated from one another.
Earthquakes: shifting of tectonic plates; may isolate populations.
Volcanic eruptions: occur near plate boundaries; may wipe out populations.

23. Movement of the Earth’s Continents over Millions of Years
Pangea’s breakup explained: Scrat’s Missing Adventure
Video Clip , Video Clip 2

24. Climate Change and Natural Selection
Cyclical climate changes restrict location/ survival of populations.
-adapt, migrate or become extinct

25. Catastrophes and Natural Selection
Collisions between the Earth & large asteroids
have occurred throughout history.
-caused destruction of ecosystems/species.
-created opportunities for new species.

26. 4-4 Biodiversity, Speciation and Extinction
Biodiversity results from the interaction between speciation and extinction.

27. Extinction Biological extinction: effects global population.
Local extinction: widespread, but not global.
Endemic species: found only in one area; particularly vulnerable to extinction.
Background extinction: typical low rate of extinction.
-1-5 species per million species/year.
Mass extinction: above background rate.
-3-5 over 500 million years.

28. Golden Toad of Costa Rica
Found in cloud forests m above sea level.
Climatic change, pollution, ultraviolet radiation, and/or fungal skin infections? No one knows why it went extinct.

29. Mass Extinctions Fig. 4-12, p. 93 Figure 4.12
Tertiary
Bar width represents relative
number of living species
Era
Period
Species and families
experiencing
mass extinction
Millions of
years ago
Ordovician: 50% of animal families, including many trilobites.
Devonian: 30% of animal families, including agnathan and placoderm fishes and many trilobites.
500
345
Cambrian
Ordovician
Silurian
Devonian
Extinction
Paleozoic
Mesozoic
Cenozoic
Triassic: 35% of animal families, including many reptiles and marine mollusks.
Permian: 90% of animal families, including over 95% of marine species; many trees, amphibians, most bryozoans and brachiopods, all trilobites.
Carboniferous
Permian
Current extinction crisis caused
by human activities. Many species
are expected to become extinct
within the next 50–100 years.
Cretaceous: up to 80% of ruling
reptiles (dinosaurs); many marine
species including many
foraminiferans and mollusks.
Triassic
Jurassic
Cretaceous
250
180 65
Quaternary
Today
Figure 4.12
Fossils and radioactive dating indicate that five major mass extinctions (indicated by arrows) have taken place over the past 500 million years. Mass extinctions leave many organism roles (niches) unoccupied and create new niches. Each mass extinction has been followed by periods of recovery (represented by the wedge shapes) called adaptive radiations. During these periods, which last 10 million years or longer, new species evolve to fill new or vacated niches. Many scientists say that we are now in the midst of a sixth mass extinction, caused primarily by human activities.
Fig. 4-12, p. 93

30. FYI The Passenger Pigeon - Gone Forever
Once the most numerous bird on earth.
In 1858, Passenger Pigeon hunting became a big business.
By 1900 they became extinct from over-harvest and habitat loss.
Figure 11-1

31. Global Extinction
Some animals have become prematurely extinct because of human activities.
Figure 11-2

32. Giant panda Black-footed ferret Whooping crane Northern spotted owl
Blue whale
Figure 11.3
Endangered natural capital: species that are endangered or threatened with premature extinction largely because of human activities. Almost 30,000 of the world’s species and 1,260 of those in the United States are officially listed as being in danger of becoming extinct. Most biologists believe the actual number of species at risk is much larger.
Mountain gorilla
Florida panther
California condor
Hawksbill sea turtle
Black rhinoceros
Fig. 11-3, p. 224

33. Speciation species arise:
Evolutionary process by which new biological
species arise:
Geographic isolation: physical isolation of populations for a long period lead to…
Reproductive isolation: mutations in geographically isolated populations prevent the production of viable offspring.

34. Geographic Isolation Can Lead to Reproductive Isolation

35. Changing Genetic Traits
Genetic engineering: alters genes by adding, deleting segments of DNA for desired trait(s).
Artificial selection: use
selective/crossbreeding
Normal mouse (left) vs. Transgenic mouse
with Human Growth Hormone

36. 4-5 The Importance of Species Diversity
Species richness: number of different species in a given area.
Species evenness: the comparative number of individuals of each species in an ecosystem.
-low evenness: few individuals of each species.
-high evenness: many individuals of each species.

37. FYI: Species Richness and Evenness
Which plot has a higher species richness? Each color represents a different species.
Which plot has a greater species evenness?

38. Variations in Species Richness and Species Evenness
High species richness Low species richness
Low species evenness High species evenness

39. Species Richness on Islands
Species equilibrium model, theory of island
biogeography.
Rate of new species immigrating should balance with the rate of species extinction
Island size and distance from the mainland need to be considered.
-small islands have a higher extinction rates.
-islands closest to the mainland have greater species richness.

40. Effects of Species Richness
Determined by two factors:
-plant productivity (more plant biomass)
-enhanced sustainability
FYI: Current hypothesis suggests that the more species, the more nutrients, the more pathways for energy flow. Our buddy, E O Wilson says,
“There’s a common sense to this: the more species you have, the more likely you’re going to have an insurance policy for the whole ecosystem”.

41. 4-6 Roles of Species in an Ecosystem
Ecological niche: role of species & everything needed for its survival.

42. Generalists Generalist species: broad niches many different locations
varied diet
tolerate wide range of conditions

43. Specialists Specialist species: narrow niches restricted habitat
restricted diet
narrow tolerance of environmental conditions

44. Five Major Species Roles in Ecosystems
Native: normal resident.
Nonnative: migrate, introduced into.
-AKA invasive, alien, exotic
Indicator: provide early warnings of damage
to communities.
Keystone: role determines types, abundance
of other species in community.
Foundation: create, enhance habitats for other
species.

45. Invasive Species

46. Deliberately Introduced Species
Purple loosestrife
European starling
African honeybee
(“Killer bee”)
Nutria
Salt cedar
(Tamarisk)
Figure 11.11
Threats to natural capital: some of the more than 7,100 harmful invasive (nonnative) species that have been deliberately or accidentally introduced into the United States.
Marine toad
(Giant toad)
Japanese beetle
European wild boar
(Feral pig)
Water hyacinth
Hydrilla
Fig a, p. 234

47. FYI: Invasive Species
The Argentina fire ant was introduced to Mobile, Alabama in 1932 from South America.
Most probably from ships.
No natural predators.
Figure 11-12

48. Indicator Species

49. Keystone Species

50. Foundation Species

51. Exam Focus Role of top predator in ecosystem.
Components of biodiversity
Link between biodiversity, speciation & extinction.
Most abundant identified species.
Steps of natural selection, including the “raw” material that drives it and its result.
Basics of geologic time scale/resulting kingdoms.
Role of plate tectonics in speciation

52. Exam Focus (cont’d) Genetic resistance.
Importance of fossil record to evolution.
Reasons for vulnerability to extinction of endemic and specialist species.
Species richness vs evenness.
Ecological niche