Principles of Paleontology

Final Exam Review

Microfossils

any evidence of past life you need to magnify to study

Foraminifera

Domain: Eukaryota

Kingdom: Rhizaria

Phylum: ___

Radiolaria

Domain: Eukaryota

Kingdom: Rhizaria

Diatom

😩 Domain: Eukaryota

Kingdom: Chomalveolata

Coccolithophore

Domain: Eukaryota

Kingdom: Chomralveolata (Algae like)

Porifera

Domain: Eukaryota

Kingdom: Animalia

sponge spicules

Ostracoda

Domain: Eukaryota

Kingdom: Animalia

Phylum: Arthropoda

Subphylum: Crustacea

Class: “seed shrimp”

Conodonta

Domain: Eukaryota

Kingdom: Animalia

Phylum: Chordata

Class: ___

Conoform (cone); Ramiform (blade); Pectiform (platform)

Embryos

juveniles of all animals ex. microfossils

Micro-vertebrates

teeth

Modern Cyanobacteria

Domain: Eubacteria

Occasionally preserved in chert

Stromatolite

Psuedofossil

A

Architarchs

Archaea, bacteria, or eukaryotes

Morphology

the study of form (size, shape, structure) of organisms and the relationship of their constituent parts

What constrains size?

metabolism/feeding

reproduction

locomotion

What do size constrains predict?

an organisms life mode

Biological Shape

dimensionless ratio of size parameters

Ratios

Can still be inadequate in defining shape

How to communicate measurement

1. Table of data

2. numerical analysis

3. graphs and plots

Drawing

removes noise

difficult subjects like bones

reconstructions

photographs

are purely objective (if unaltered)

Models

1. Mathematical Equation (coiling model to build the shape

2. Landmark analysis - eliminates size and distortion, only looks at shape

3. Harmonic analysis

Variables in similar groups

more characters, more detail

features will only be applicable to a few groups

Variables in higher taxa

fewer characters, less detail

applicable to more groups

Ontogeny

life history of an organism

Direct Development

zygote - adult through gradual change

Indirect development

zygote - larval stage - adult

abrupt metamorphosis

95% of marine invertebrates

Marine invertebrate Larvae

Planktic

Marine invertebrate Adults

Benthic

Cross Section analysis

plotting variation in assemblage presumed to present various growth stages (multiple specimens)

Longitudinal analysis

One individual

plotting growth in single individuals

requires growth lines

Coordinate Transformation

compares landmarks between 2 growth stages

juvenile vs adult

Determinate Growth

rapid early growth, flattens toward adult hoot

more common

Indeterminate growth

many invertebrates continue to grow as long as they live and eat

problem: population comparisons

Isometric growth

ratio between any 2 measurements does not change

ie. shape does not change from juvenile to adult

Anisometric growth

ratio between 2 measurements does change throughout ontogeny

What does Surface Area/Volume ration effect?

1. Respiration/absorption

2. Strength

3. metabolism/heat

4. adhesion vs. Gravity

How to adjust for surface area/volume problems

1. Anisometric growth

2. Complex structures (convolutions)

3. Large organisms need to increase girth of their bones proportionally more to support themselves

4. Unused material in volume (inert material)

Allometry

the growth of body parts at different rates, resulting in a change of body proportions

study the relationship of body and size

Y = _bX^a

Log (Y) = aLog(X) + Log(b)

Positive Allometry

Y increases at a faster rate than X

Negative Allometry

Y increases at a slower rate than X

Brain mass vs. Body Mass

Human Ontogeny

Encephalization

enlarged brain relative to an allometric trend

Examples of Allometry

Brain mass vs Body mass

Metabolic Rate vs Body mass

Muscle characteristics vs fiber number/weight

Heterochrony

Evolutionary changes in the timing of development

Paedomorphosis

descendant adults resemble ancestor juveniles

Hypermorphosis

process can either end later or extends development

aka adult descendant looks older than adult ancestor

Classification

arrangement of objects according to a system or principle

Classification in paleontology

an outline of evolutionary history

Monophyletic Classification

a group contains an ancestor and all of its descendant members

Paraphyletic classification

a group contains an ancestor and only some of its descendants

Polyphyletic classification

a group of unrelated members

Orthodox Classification

organisms are grouped on the basis of features that seem to reflect their common ancestry

Disadvantages of Orthodox classification

subjective

difficult to reproduce

untestable

Phenetic Classification

Organisms grouped on overall similarity

Steps for phenetic classification

1. identify as many features as possible

2. record features in a data matrix; code matrix

3. derive similarity table

4. sort into groups (phenogram)

5. produce formal classification

6. evaluate plausibility

Advantages of Phenetic Classification

objective

all characters/features hold equal weight

lots of features

can group anything

Disadvantages of phenetic classification

convergence isn’t considered as a factor for similar features

can group anything

Cladistics

Organisms are grouped on features that all members possess

Cladogram

branching diagram with taxa at the ends, relative position reflects evolutionary sequence

There is no ancestor

No depiction of time

Apomorphy

derived character/feature

Synamorphy

shared derived character/feature

Pleisiomorphy

primitive character

Synpleisiomorphy

shared primitive character

Node

represents hypothetical common ancestor at the branch tops and is defined by synamorphies that unite those taxa

Outgroup

primitive relative of the clade used to “root” the tree

Advantages of Cladistics

objective

reproducible

testable

Disadvantages of cladistics

Does not produce convenient nomenclature higher taxonomic groups; New naming system proposed - Phylogenetic systematics

Parsimony

Shortest number of steps

calculate every possible arrangement and go with the simplest/least steps

Bayesian

Probability based on prior observation