1. Biodiversity

2. Biodiversity
Biological Diversity or Biodiversity, is the variety of the earth’s species, the genes they contain, the ecosystems in which they live, and the ecosystems processes such as energy flow and nutrient cycling.

3. Biodiversity Biodiversity
increases with speciation
decreases with extinction
Give-and-take between speciation and extinction  changes in biodiversity

4. Why Biodiversity is important?
It supplies us with food, wood, energy, medicines,…
It preserves the air and water quality and maintains the fertility of soils.
It helps us to dispose of wastes and to control populations of pests

5. In carrying out these free ecological services, which are also part of the earth’s natural capital, biodiversity helps to sustain life on the Earth.

6. Biological Evolution by Natural SELECTION

7. Idea Early Greek philosophers
Wallace and Darwin (1858) independently proposed the concept of natural selection as a mechanism for biological evolution’
But Darwin gathered evidence and publish it in 1859 in his book, On the Origin of Species by Means of Natural Selection

8. Charles Darwin 1809-1882 British naturalist
Proposed the idea of evolution by natural selection
Collected clear evidence to support his ideas

9. Darwin’s Observations
Most species produce more offspring than can be supported by the environment
Environmental resources are limited
Most populations are stable in size
Individuals vary greatly in their characteristics (phenotypes)
Variation is heritable (genotypes)

10. Darwin’s finches 13 species of finches in the Galápagos Islands
Was puzzling since only 1 species of this bird on the mainland of South America, 600 miles to the east, where they had all presumably originated
Darwin noted that the plants and animals of South America were very distinct from those of Europe.
Organisms from temperate regions of South America were more similar to those from the tropics of South America than to those from temperate regions of Europe.
Further, South American fossils more closely resembled modern species from that continent than those from Europe.

11. Darwin’s finches Differences in beaks
associated with eating different foods
adaptations to the foods available on their home islands
Darwin concluded that when the original South American finches reached the islands, they adapted to available food in different environments

13. What did Darwin say?
Organisms reproduce more than the environment can support
some offspring survive
some offspring don’t survive
competition
for food
for mates
for nesting spots
to get away from predators

14. Survival of the fittest
Who is the fittest?
traits fit the environment
the environment can change, so who is fit can change
Peppered moth

15. According to this theory, life has evolved into six major groups of species, called Kingdoms.
Tree of life (development of life)

16. At any given moment (e.g. the ‘present’), all we see is current diversity… all extinct forms are gone (99.9%)
Time 

18. Lamarck
Lamarck’s theory stated that organisms evolve over time due to the environmental factors that act upon that organism
If they began to use an organ more than they had in the past, it would increase in its lifetime.
Meanwhile organs that organisms stopped using would shrink.

19. Fossil Record: The world’s cumulative body of fossils found.
Fossils: Mineralized or petrified replicas of skeletons, bones,… or impressions found in rocks
Strongest evidence for evolution

20. Main cause of evolutionary change:
Mutation: random changes in the structure or number DNA molecules in a cell that can be inherited by offspring.
Mutations can occur in any cell, but only those taking place in reproductive cells are passed on to offspring.
New genetic traits that give better chances for survival (now or in the future)

21. Populations evolve when genes mutate and give some individuals genetic traits that enhance their abilities to survive and to produce offspring with theses traits (natural selection)

22. Adaptation
An adaptation or adaptive trait, is any heritable trait that enables and individual organism to survive through natural selection and to reproduce more than other individuals under prevailing environmental conditions

23. For natural selection to occur,…
The trait must be heritable.
The trait must lead to differential reproduction, which enables individuals with the trait to leave more offspring than other members of the population.

24. Genetic Resistance
Genetic resistance is the ability of one or more organisms in a population to tolerate a chemical design to kill it. (Ex. Bacteria)

25. Natural Selection acts in individuals, but evolution occurs in populations

26. When environmental conditions change:
A population of a species faces 3 possible futures:
Adapt
Migrate
Become extinct

27. Humans
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28. How long does it takes?
Populations of genetically diverse species that reproduce quickly often adapt to a change in short time.
Species that cannot reproduce large numbers of offspring rapidly, take long time to adapt.

29. 3 Common myths
Survival of the fittest means survival of the strongest.
Organisms develop certain traits because they need or want them.
Evolution by natural selection involves some grand plan of nature in which species become more perfectly adapted.

30. Speciation
Tectonic plate movements, volcanic eruptions, earthquakes, and climate change have shifted wildlife habitats, wiped out large number of species, and created opportunities for the evolution of new species.

31. Speciation One species can evolve into two or more species
2 step process
Geographical isolation
Reproductive isolation
When a group becomes geographically isolated over time it will become reproductively isolated = new species formed. 31

32. Ammospermophilus spp
Geographic isolation
When a population becomes divided by a natural barrier.
Mountains, river, body of water, landslides
Groups can’t interbreed or intermix
Become adapted to a different environment
Harris’s antelope squirrel inhabits the canyon’s south rim (L). Just a few miles away on the north rim (R) lives the closely related white-tailed antelope squirrel 32

33. Reproductive Isolation
Differences in isolated groups become so great, they can no longer interbreed
Physical changes
Behavioral changes
Biochemical changes 33

34. How long does it takes the speciation?
For some rapidly reproducing organisms, this may occur within hundreds of years.
For most species, it takes from tens of thousands to millions of years.

35. Extinction
Extinction of a species occurs when it ceases to exist; may follow environmental change - if the species does not evolve
Evolution and extinction are affected by:
large scale movements of continents
gradual climate changes due to continental drift or orbit changes
rapid climate changes due to catastrophic events

37. Extinction: Lights Out
Extinction occurs when the population cannot adapt to changing environmental conditions.
The golden toad of Costa Rica’s Monteverde cloud forest has become extinct because of changes in climate.
Figure 4-11

38. Extinction
Background extinction - species disappear at a low rate as local conditions change
Mass extinction - catastrophic, wide-spread events --> abrupt increase in extinction rate
Five mass extinctions in past 500 million years

39. How many mass extintions?
Some biologists argue that a mass extintions should be distinguished by a low speciation rate as well as by a high rate of extintion.
Under this: only 3 mass extintions.

40. A mass extintion provides an opportunity for the evolution of new species that can fill unoccupied ecological roles or newly created ones.

41. Species Diversity: Richness vs. Evenness
Species Richness: measurement of the
number of species in a given area
Species Evenness: measurement of how
evenly distributed organisms are among
species
Community A Community B
species
species
species
species
species

42. Species richness appears to increase the productivity and stability or sustainability of an ecosystem.
While there may be some exceptions to this, most ecologists now accept this as a useful hypothesis

43. the species’ occupation and its
Niche is
the species’ occupation and its
Habitat
location of species
(its address)

44. Niche
A species’ functional role in its ecosystem; includes anything affecting species survival and reproduction
Range of tolerance for various physical and chemical conditions
Types of resources used
Interactions with living and nonliving components of ecosystems
Role played in flow of energy and matter cycling

45. Scientists use the niches of species to classify them broadly as: Generalist species Specialists species

46. Types of Species Generalist large niches Live in many places
Eat a variety of food
tolerate wide range of environmental variations
do better during changing environmental conditions
Such as flies, cockroaches, mice, rats, humans,…

47. Types of Species Specialist narrow niches
May be able to live in only one type of habitat
Use one or a few types of food
Tolerate a narrow range of climatic and other environmental conditions
more likely to become endangered
do better under consistent environmental conditions
Such as tiger salamanders, China´s giant panda

48. Specialist species Generalist species with a narrow niche
Fig. 4-7, p. 91
Specialist species
with a narrow niche
Generalist species
with a broad niche
Niche
separation
Number of individuals
Figure 4.7
Overlap of the niches of two different species: a specialist and a generalist. In the overlap area, the two species compete for one or more of the same resources. As a result, each species can occupy only a part of its fundamental niche; the part it occupies is its realized niche. Generalist species such as a raccoon have a broad niche (right), and specialist species such as the giant panda have a narrow niche (left).
Niche
breadth
Region of
niche overlap
Resource use
Fig. 4-7, p. 91

49. Generalist Species
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50. Any given species may play one or more of five important roles- native, nonnative, indicator, keystone, or fundation roles – in a particular ecosystem.

51. Types of Species
Native species normally live and thrive in a particular ecosystem
Nonnative species are introduced - can be called exotic or alien
Indicator species serve as early warnings of danger to ecosystem- birds & amphibians
Keystone species are considered of most importance in maintaining their ecosystem
Foundation species help to create habitats and ecosystems

52. Nonnative Species
Nonnative plant species are invading the nation's parks at an alarming rate, displacing native vegetation and threatening the wildlife that depend on them
At some, such as Sleeping Bear Dunes National Lakeshore in Michigan, as much as 23 percent of the ground is covered with alien species, and the rate of expansion is increasing dramatically.

53. Indicator Species
a species whose status provides information on the overall condition of the ecosystem and of other species in that ecosystem
reflect the quality and changes in environmental conditions as well as aspects of community composition

54. Keystone Species
A keystone is the stone at the top of an arch that supports the other stones and keeps the whole arch from falling
a species on which the persistence of a large number of other species in the ecosystem depends.
If a keystone species is removed from a system
the species it supported will also disappear
other dependent species will also disappear
Examples
top carnivores that keep prey in check
large herbivores that shape the habitat in which other species live
important plants that support particular insect species that are prey for birds
bats that disperse the seeds of plants