ESS 104 Midterm 1

Formation of the Earth

4\.6 billion years ago

The oldest thing on Earth, a zircon, was found in:

Australia

Plate tectonics have a profound impact on Earth’s living systems and our understanding of them. Why?

The configuration of the continents helps determine ocean circulation. Geographic isolation and proximity can be drivers of evolution. Subduction has destroyed most of the older rocks on Earth, thus destroying any fossils that might have existed in them.

What are the earliest fossils on Earth?

Biomarkers, isotopic fractionations and chemical fossils

Formation of the Moon

4\.5 billion years ago

Initiation of plate tectonics

3 billion years ago

Oxygenation of the Earth

2\.5 billion years ago

The event that occurred between 2400 and 2200 mya (2.4 and 2.2 billion years ago) and enabled life as we know it today was:

The Great Oxidation Event

Scientists who study fossils of organisms other than humans are:

paleontologists

Fossil beds are composites. This means:

They may include fossils brought in from somewhere else. They are time-average.

The atmosphere of the Early Earth consisted primarily of:

Nitrogen and carbon dioxide

The study of sequences of rocks in time is called:

stratigraphy

Fossils are:

evidence of life preserved in rocks

Fossils are preserved in __________ rocks

sedimentary

The three types of fossils are:

body, trace, and chemical

What has to happen for an organism to become a fossil?

Death, rapid burial, preservation, lithification (becoming a rock), erosion and exposure

The Green River shale, Burgess Shale, Solnhofen Limestone and Chengjiang are examples of:

lagerstatten

The vast majority of fossils are found in:

sediments deposited in shallow lakes, lagoons or flood plains

The study of hierarchical relationships and naming of organisms is called:

taxonomy

The paleontology species concept is NOT based on

DNA

One of the best examples of an evolutionary series that is strong evidence for evolution was collected by:

O.C. Marsh

A fundamental grouping of organisms that descended from a common ancestor is a:

phylogeny

What is NOT a problem for paleontologists when setting up a new species?

Evolutionary series

Ontogenetic, population and taphonomic are all types of

variation that hinder paleontologists in recognizing species

The environment in which sediment was laid down is called

depositional environment

The relative time scale used by all geologists world-wide is mostly based on

marine fossils

Replacement/Permineralization fossil

Dissolved compounds in ground water swap out shell and skeleton material

Cast/Mold fossil

Sediment fills in around and inside the organism and the hard parts dissolve

Chemical fossil

chemicals preserved that provide an organic signature for life including itsotopes and biomarkers preserved in rocks

Mummification fossil

Organism is desiccated and preserved in a very dry environment

Freezing fossil

Organism is preserved in ice

The processes involved in fossilization are known as

taphonomy

Convergent evolution

Similar structures or traits that develop independently on different organisms to solve the same problem

Darwin’s preferred model of evolution was

phyletic gradualism

Erasmus Darwin was

Charles Darwin’s grandfather, thought transmutation was driven by competition and sexual selection and all life came from a common ancestor but didn’t have evidence

Jean-Baptiste Lamarck was

The man who developed the first cohesive theory of evolution after his studies of biology, called it transmutation and thought acquired traits were inherited

A species can have one of two fates

Extinction or speciation

Body fossils

Hard parts of an organism, such as bone, teeth or shells

Trace fossils

not actual biological material but provide evidence of the activities of ancient organisms, coprolites, tracks, eggs

Natural selection is driven by

competition for sexual partners, space and food

Natural selection

The process in which heritable variations that result in better adaptations to a changing environment result in a new species

phyletic gradualism

evolution that occurs slowly in a very stable environment

punctuated equilibrium

pattern of evolution in which long stable periods are interrupted by brief periods of more rapid change, unstable environment

extinction

to die out completely

background extinction

the extinction that goes on all the time in relatively small numbers, caused by biological causes and natural selection

mass extinction

when global extinction rates rise dramatically for a geologically short time

mass extinction characteristics

geologically rapid, involves a significant number of organisms from different phyla and is global

how many mass extinctions have there been?

5 (Ordovician Silurian, Devonian, Permian Triassic, cretaceous-tertiary)

The generally accepted cause of the end-Cretaceous mass extinction was

a meteorite/bolide impact

evidence for a meteorite impact at the end of the Cretaceous includes

high iridium levels, tektites and shocked quartz

The crater believed to be the one formed by the end-Cretaceous meteorite is near

the Yucatan Peninsula, Mexico

The largest mass extinction was

end-Permian (or Permian-Triassic), 95% of marine animal species exterminated, entire classes & orders disappeared

The cause of the end-Permian mass extinction is

still not known for sure, but the ocean became inhospitable

explosive radiation

the geologically sudden increase of global species diversity

mass extinction results in

explosive radiation due to vacant ecological niches

Most of the body plans on Earth arose

during the Cambrian radiation

The three evolutionary faunas recognized by Jack Sepkoski are

Cambrian, Paleozoic, Modern

Which phyla has no symmetry?

sponges (Porifera)

The basis of Functional Morphology is

form follows function

In functional morphology, biomechanics is used to

decide what really is possible

In evolution, compromise occurs because

nature is parsimonious and wants to use the fewest resources, therefore it will not expend energy for an unnecessary adaptation

Convergent evolution demonstrates functional morphology because

similar structures evolve to solve the same problems

Convergent evolution happens because

there are a limited number of morphologies that will perform a function successfully

We figured out what a Dire Wolf looked like by using

comparison

Functional morphology

the study of structural adaptations an organism makes to its environment and lifestyle

What is not true of morphological features?

They are usually neutral (features are NOT usually neutral, meaning they almost always have a purpose, a neutral feature would be eye color)

paleontology

the study of fossils

What are problems with the fossil record?

Physical destruction, rarefaction (preservation bias), age bias

Biological species concept

species is a group of populations whose members have the potential to produce fertile offspring

ontogenetic variation

changes that you can see between young individuals and old individuals of the same species

population variation

genetic differences between local populations

taphonomic variation

when geological processes like plastic deformation change the shape of a bone, resulting in apparent anatomical differences

microevolution

evolutionary change within a species or small group of organisms, especially over a short period

macroevolution

large-scale evolutionary changes that take place over long periods of time

divergent evolution

dissimilar organs that have a similar origin and underlying anatomy

What are the nature of morphological features?

they are mostly adaptive, very few neutral (non-functional) features, only a limited number of ways an organism can adapt to its environment, most options are already in use by extant organisms, many fossil morphological features can be extrapolated from a living equivalent, adaptation is non-random

pseudo fossils

not actual fossils, they are minerals or rocks that happen to look like fossils

unaltered/original material

dead organism has been incorporated into the rock but has not undergone the permineralization or replacement processes

permineralization

new material fills in the void spaces of a dead organism

replacement

the organisms original materials are replaced with new ones

bilateral symmetry

the organism is mirrored down the center

radial symmetry

the organism has repeated segments arranged around a central point

chirality

symmetry that involves rotation as well as reflection

five-point symmetry

the organism has five matching segments repeated around a central point, ex. starfish