Fossils Flashcards
What are fossils
The remains of organisms that lived a long time ago and were conserved, especially in sedimentary rocks.
What is a biome
The largest ecological unit in the biosphere comprised of a large geographical area with a characteristic fauna and flora
What is an ecosystem
The abiotic components of an environment are co-dependent on one another and influence each other
Give the two types of forest
Afro-montane(mountain)
Sub-tropical rain forest
How are trees arranged in a forest?
Crown
Middle layer(made up of smaller trees and shrubs)
Lower level of ferns and herbaceous plants
What indicates poor soil in southern forests
Blackish brown water
Name the dating methods
Relative dating Paleomagnetic dating Fauna comparisons Dendrochronological comparisons Radiometric dating
What are the different types of fossils?
Form fossils Body fossils Moulds Trace fossils Unchanged fossils
What is a mass extinction
When massive numbers of species all over the world die simultaneously
What is biogeography
Branch of biology that deals with the geographical distribution of plants and animals
What is the most primitive form of life on earth
A group of bacteria known as archaea
What group of bacteria developed from archaeabacteria
Eubacteria
Where were cyan bacteria found
Barberton
Why was the development of cyan bacteria that gave of oxygen as waste product of photosynthesis extremely important
Life could now exist anywhere on earth and not only around the warm water
Light energy was used for this process
Only ground substances needed were water and carbon dioxide, both available in abundance
Oxygen was produced as waste product
Give the evidence that indicated that a meteorite collision 65mya did cause a mass extinction
Large amounts of iridium in rock layers of this period which are rare in rocks of earth but abundant in meteorites
Shock quartz formed in conditions of extreme impacts and speed can be found in rock layers
An impact crater found in the sea
What is the name of the oldest and biggest crater known and where is a t located
The Vredefort dome near Parys
Ash and dust from volcanic eruptions hung in a dense cloud over the earth and blocked rays of sun causing:
A cooling down of the earth trapping water in ice caps, causing sea levels to lower and aquatic habitats were changed
Photosynthesis couldn’t occur causing food webs to collapse. An oxygen deficiency resulted causing more organisms to die
Why are fossils important?
We can study:
Trends in biodiversity with the aim of understanding current biodiversity issues
Evolutionary relationships and understand more about modern species
Forming of sediments helping us to understand environmental changes of the past and present
We can explore for the minerals especially for mining
Why is the fossil record not very complete or representative?
Only 0,1% of all organisms that ever lived formed fossils
Most fossils are from aquatic organisms where sedimentation occurs more readily
Many organisms don’t have hard parts to form fossils
What is biodiversity
The variety of organisms that can be foundation by the earth, as well as the interaction between them
Genus
Related species are grouped in genus
