Chapter 1: Palaeontology as a science
Fossils = the remains of any ancient organism.
Palaeontology = the study of the life of the past. The key value of palaeontology has been to show us
the history of life through deep time
Palaeontology in the modern world:
1. Origins: where did life come from?
2. Curiosity about different worlds
3. Climate and biodiversity change: climate change and future of the Earth
4. The shape and tempo of evolution: tree of life
5. Extinction
6. Dating rocks: biostratigraphy = the use of fossils in dating rock. This was previous the main
reason.
Palaeontology through time:
Fossils were used as magical stones in Roman and medieval times. Leonardo da Vinci used his
observations of modern plants and animals, and of modern rivers and seas, to explain the fossils sea
shells found high in the Italian mountains. Later Nicolaus Steno demonstrated the true nature of
glossopetra simply by dissecting the head of a huge modern shark and showing that its teeth were
identical to the fossils. Robert Hooke also gave detailed descriptions of fossils. He was the first to hint
at the idea of extinction. Georges Cuvier demonstrated the reality of extinction. He realized that all
organisms share common structures (comparative anatomy). Charles Lyell believed that the fossil
record showed no evidence of long-term change but rather cycles of change. Jean-Baptiste came up
with the idea of evolution. Charles Darwin developed the theory of evolution by natural selection.
Palaeontologists also made progress in understanding the earlies stages in the evolution of life.
Collecting fossils is still used today in macroevolution, a field that studies rates of evolution, the
nature of speciation, the timing and extent of mass extinctions, the diversification of life etc. Charles
Walcott found the Burgess Shale fauna, with many new species.
Classical and medieval views about fossils were often magical and mystical. In the 16 th and 17th
century observations showed that fossils were the remains of ancient plants and animals. By 1800,
many scientists accepted the idea of extinction. By 1830, most geologists accepted that the Earth was
very old. By 1840, the major diversion of deep time (stratigraphic record) had been established by
the use of fossils. It was seen that fossils showed directions in the history of life. By 1860, evolution
explained this.
Science consists of testing hypotheses.
Research in palaeontology has many facets:
- Finding new fossils
- Using quantitative methods to answer questions about paleobiology, paleogeography,
macroevolution, the tree of life and deep time.
, Chapter 6: Fossil form and function
Fossils species are identified according to their external form. The form of any organism is shaped by
evolution, by adaptations from either natural or sexual selection.
1. Form is the only evidence we have in the fossils for identifying species and wider
relationships to reconstruct the tree of life.
2. Form can tell us about behaviour and ecology
3. Variations in form are commonplace within a species and the study of changes in form
through time informs us about evolution.
Species concept:
- Biological: for modern plants and animals, but needs interbreeding
- Morphological: the bounds of a species entirely on form. All members of a species should
look similar. The true species boundary might however be missed.
Variations in form within species:
1. Individual variation
2. Geographic variation: physical differences in species that live elsewhere
3. Sexual dimorphism: males and females have different characteristics within a species
4. Growth stages: different stages from larval to adult
5. Ecophenotypic effects: local ecological conditions affect the form of an organism, so the
organism changes throughout its lifetime.
Allometric = different measure growth, so the proportion of for example the eyes changes through
an organism its lifetime. Positive = when the growth increases faster that the isometric expectation.
Negative = when the growth is slower that the isometry.
Isometric = an organism has the same measures during its lifetime.
Within any clade there are many forms. Relates organisms usually show some common aspects of
forms but have differences. The range of forms within a clade is the disparity (= the sum of
morphological variation).
Ontogeny = developend (growth from an embryo to adult) and phylogeny = evolutionary history. The
general characters first develop (ontogeny), after which the special characters develop (phylogeny).
The external form (phenotype) of an organism is controlled by the genetic code (genotype). There
are a number of development genes that determine fundamental aspects of form (symmetry,
anteroposterior orientation and limb differences).
Functional morphology: the assumption is that biological structures are adapted in a way that they
are efficient. Examples are: hard skeletons, limbs, pallial line and muscle scars.
- Comparison with modern analogs: there are two issues, phylogeny (relations with animals)
and functional analogs (anatomic parellels).
- Biomechanical modelling: make interpretations of movements. It may be used to access how
the design of an ancient organism matches the hypothetical forces acting on it. They are easy
to produce, but it is important to check all possible gaits have been cosiderded.
- Circumstantial evidence: clues about lifestyles
1. Preserved in sedimentary rocks: deposition conditions
2. Associated fossils: food web, life habits
3. Associated trace fossils: linked to their producers
4. Body fossils: preserve evidence of soft tissue
Fossils = the remains of any ancient organism.
Palaeontology = the study of the life of the past. The key value of palaeontology has been to show us
the history of life through deep time
Palaeontology in the modern world:
1. Origins: where did life come from?
2. Curiosity about different worlds
3. Climate and biodiversity change: climate change and future of the Earth
4. The shape and tempo of evolution: tree of life
5. Extinction
6. Dating rocks: biostratigraphy = the use of fossils in dating rock. This was previous the main
reason.
Palaeontology through time:
Fossils were used as magical stones in Roman and medieval times. Leonardo da Vinci used his
observations of modern plants and animals, and of modern rivers and seas, to explain the fossils sea
shells found high in the Italian mountains. Later Nicolaus Steno demonstrated the true nature of
glossopetra simply by dissecting the head of a huge modern shark and showing that its teeth were
identical to the fossils. Robert Hooke also gave detailed descriptions of fossils. He was the first to hint
at the idea of extinction. Georges Cuvier demonstrated the reality of extinction. He realized that all
organisms share common structures (comparative anatomy). Charles Lyell believed that the fossil
record showed no evidence of long-term change but rather cycles of change. Jean-Baptiste came up
with the idea of evolution. Charles Darwin developed the theory of evolution by natural selection.
Palaeontologists also made progress in understanding the earlies stages in the evolution of life.
Collecting fossils is still used today in macroevolution, a field that studies rates of evolution, the
nature of speciation, the timing and extent of mass extinctions, the diversification of life etc. Charles
Walcott found the Burgess Shale fauna, with many new species.
Classical and medieval views about fossils were often magical and mystical. In the 16 th and 17th
century observations showed that fossils were the remains of ancient plants and animals. By 1800,
many scientists accepted the idea of extinction. By 1830, most geologists accepted that the Earth was
very old. By 1840, the major diversion of deep time (stratigraphic record) had been established by
the use of fossils. It was seen that fossils showed directions in the history of life. By 1860, evolution
explained this.
Science consists of testing hypotheses.
Research in palaeontology has many facets:
- Finding new fossils
- Using quantitative methods to answer questions about paleobiology, paleogeography,
macroevolution, the tree of life and deep time.
, Chapter 6: Fossil form and function
Fossils species are identified according to their external form. The form of any organism is shaped by
evolution, by adaptations from either natural or sexual selection.
1. Form is the only evidence we have in the fossils for identifying species and wider
relationships to reconstruct the tree of life.
2. Form can tell us about behaviour and ecology
3. Variations in form are commonplace within a species and the study of changes in form
through time informs us about evolution.
Species concept:
- Biological: for modern plants and animals, but needs interbreeding
- Morphological: the bounds of a species entirely on form. All members of a species should
look similar. The true species boundary might however be missed.
Variations in form within species:
1. Individual variation
2. Geographic variation: physical differences in species that live elsewhere
3. Sexual dimorphism: males and females have different characteristics within a species
4. Growth stages: different stages from larval to adult
5. Ecophenotypic effects: local ecological conditions affect the form of an organism, so the
organism changes throughout its lifetime.
Allometric = different measure growth, so the proportion of for example the eyes changes through
an organism its lifetime. Positive = when the growth increases faster that the isometric expectation.
Negative = when the growth is slower that the isometry.
Isometric = an organism has the same measures during its lifetime.
Within any clade there are many forms. Relates organisms usually show some common aspects of
forms but have differences. The range of forms within a clade is the disparity (= the sum of
morphological variation).
Ontogeny = developend (growth from an embryo to adult) and phylogeny = evolutionary history. The
general characters first develop (ontogeny), after which the special characters develop (phylogeny).
The external form (phenotype) of an organism is controlled by the genetic code (genotype). There
are a number of development genes that determine fundamental aspects of form (symmetry,
anteroposterior orientation and limb differences).
Functional morphology: the assumption is that biological structures are adapted in a way that they
are efficient. Examples are: hard skeletons, limbs, pallial line and muscle scars.
- Comparison with modern analogs: there are two issues, phylogeny (relations with animals)
and functional analogs (anatomic parellels).
- Biomechanical modelling: make interpretations of movements. It may be used to access how
the design of an ancient organism matches the hypothetical forces acting on it. They are easy
to produce, but it is important to check all possible gaits have been cosiderded.
- Circumstantial evidence: clues about lifestyles
1. Preserved in sedimentary rocks: deposition conditions
2. Associated fossils: food web, life habits
3. Associated trace fossils: linked to their producers
4. Body fossils: preserve evidence of soft tissue
