15.1 The diversity of life is based on the origin of new species

1
15.1 The diversity of life is based on the
origin of new species
2
I. What is a Species?

• A. Biologist define a species as a population
  whose members have the ability to breed with one
  another in nature and produce fertile offspring.
• B. This is referred to as the Biological Species
  Concept

3
II. From Microevolution to Macroevolution

• A. Earlier we saw microevolution refers to a
  change in the allele frequency in a population.
• B. Macroevolution is a dramatic change
• New species evolving (speciation)
• Extinction of species
• New features of living things
• C. Speciation leads to an increase in biologic
  diversity

4
III. Reproductive barriers between species

• A. Reproductive isolation is a condition that
  keeps two species from interbreeding.
  Reproductive isolation usually involves two or
  more of the following, but just one is sufficient
  for isolation to happen
• Timing- breeding seasons occur at different times

5
Reproductive barriers

• Behavior- different mating behaviors prevent
  successful mating
• Habitat- species are adapted to specific habitats
  in the same area and dont interact
• Structure- reproductive structures are
  incompatible
• Sterility- mating may occur but offspring are
  sterile due genetic differences

6
IV. Geographic isolation and Speciation

• A. When one species becomes physically separated
  into two populations, the separation may lead to
  two distinct species through microevolution. This
  is called Geographic isolation.

7
Geographic isolation

• B. Species can become geographically isolated
  from each other in two ways
• 1. Geography of the Earth may change and
  separate a species
• 2. The species may be dispersed or moved to
  different point on the globe by other methods
  (stowaways on ships or planes)

8
Geographic Isolation
9
Population Evolution
10
V. Adaptive Radiation

• A. When multiple species arise from one common
  ancestor and spread-out to and adapt to different
  habitats this is known as Adaptive Radiation.
• B. The numerous types of finches in the
  Galapagos Islands are an example of adaptive
  radiation.

11
Adaptive radiation
12
Adaptive radiation
13
VI. Tempo or Speed of Speciation

• When species diverge in spurts of relatively
  rapid change, then these new species may remain
  unchanged for an extremely long period in the
  fossil record this is known as Punctuated
  Equilibrium.

14
Adaptation Models
15
15.2 Evolution is usually a remodeling process
16
I. Refinement of Existing Adaptations

• A. Complex structures may have evolved from a
  similar structure having the same basic function
• B. An example of this would be the eye which has
  many interacting parts

17
Complexity of eye
18
II. Adaptation of Existing Structures to New
Functions

• A. There are thousands of instances where
  existing materials or structures evolved into new
  adaptations
• B. Chitin originated to help marine animals from
  predators, now it is found in land animals and it
  is used to fight dehydration
• C. The flippers of penguins are another example
  of using old structures for new functions

19
III. Evolution and Development

• A. Embryology is the study of the processes of
  multicellular organisms as they develop from
  fertilized eggs to fully formed organisms
• B. Genes that control the development of an
  organism are of particular importance
• C. Sometimes the timing or rate of development
  plays a role in evolution

20
Remodeling Process

• Ground and Tree Dwelling

21
15.3 The fossil record provides evidence of
lifes history
22
I. How Fossils Form

• A. Soft body parts usually decay quickly, and
  hard parts like bone, teeth and shells may become
  fossils
• B. Fossils arent always bone, they can be
  footprints, burrows, impressions or even dung

23
Fossils
24
II. The Fossil Record and Geologic Time Scale

• A. The Geologic Time Scale organizes Earths
  History into four distinct ages known as the
  Precambrian, Paleozoic, Mesozoic and Cenozoic
  Eras
• B. Eras are divided into periods and the periods
  are divided into epochs
• C. New eras are recognized by a major change in
  the life forms of that time

25
Geologic Time Scale
26
Geologic Eras

• 4.6 bya- Precambrian (cells appear simple
  animals)
• 540 mya- Paloezoic (complex animals plants)
• 245 mya- Mesozoic (dinosaurs mammals)
• 65 mya- Cenozoic (mammals humans)

27
III. Dating Fossils

• A. Radiometric dating measures certain
  radioactive isotopes to determine the ages of
  rocks and fossils
• B. Half-Life is the number of years it takes for
  50 of the original sample to decay ya(1-r)t
• C. The half-life is unaffected by temperature,
  pressure and other environmental conditions

28
Radioactive Isotopes

• Carbon 14 -gt carbon 12 (living -bone, plants)
• Isotope (more neutrons) -gt normal
• Uranium 238 --gt Lead 206 (volcanic rock)
• 100 of isotope present time
• Less isotope -gt older the material

29
Radioactive Isotopes and Age
30
Half-Life
31
IV. Continental Drift and Macroevolution

• A. Landmasses on different plates change position
  relative to one another known as continental
  drift
• B. There are two major events of continental
  drift that had a major impact on the history of
  life
• 1. 250 million years ago all the plates moved
  together forming Pangea
• 2. 180 million years ago Pangea began to break
  up, isolating the continents

32
Continental Drift
33
V. Mass Extinctions

• A. Earth had relatively long periods of stability
  broken by brief episodes of great species loss
  known as mass extinctions
• B. Extinctions occur all the time but there have
  been five or six distinct periods of mass
  extinction over the last 600 million years
• C. After every extinction the surviving organisms
  have a new opportunity to change

34
15.4 Modern taxonomy reflects evolutionary history
35
I. What is Taxonomy?

• A. Taxonomy involves the naming and
  classification of organisms
• B. The goal is to reduce confusion and organize
  life into larger groups or related species

36
Classification
37
II. The Linnaean System of Classification

• A. Carolus Linnaeus developed a system that uses
  a two part Latin name for each species and a
  hierarchy of species into broader groups
• B. The two part name is binomial which means the
  first name is the genus and the second name is
  the species

38
Kingdoms
39
5 Kingdoms

• Monera - bacteria (prokaroyote)
• Protista- amoeba (single cell)
• Animal- platypus
• Plant- fern
• Fungi- mushroom
• Virus (Non-living?) a kingdom?

40
III. Classification and Evolution

• A. A diagram that reflects evolutionary
  relationships has a branching pattern called a
  phylogenetic tree
• B. Convergent Evolution is a process in which
  unrelated species from similar environments have
  adaptations that seem similar
• C. Similar adaptations that result from
  convergent evolution are called analogous
  structures

41
Phylogenic Tree
42
Classification Groups (Linnanean)

• Kingdom (largest 5 of them) --gt Phylum --gt Class
  --gt Order --gt Family --gt Genus --gt Species
  (millions of them)

43
5 Kingdom / 3 Domain
44
IV. Molecular Data as a Taxonomic Tool

• A. The relatedness of species can be measured by
  comparing genes and gene products
• B. This evidence is independent of structural data

45
V. Cladistics

• A. Cladistics is the scientific search for
  ancestral relationships among species
• B. Each branch on a cladogram is called a clade
  every clade consists of an ancestral species and
  all of its descendants
• C. Derived characters are homologous
  characteristics that unite the organisms as a
  group

46
Cladogram
47
Cladogram
48
VI. Comparing Classification Schemes

• A. The Kingdom is the broadest taxonomic category
  
• B. Biologists have gone from a two-kingdom
  system, three-kingdom system, five-kingdom system
  and now to a three domain system

49
Re-examining Classification
50
Redis Experiment
51
(No Transcript)