6th extension mod 1

How many currently known species

2.3 million

Almost all primates including humans show up just before

3 to 4 MYA

Formation of earth

4.6 BYA

First organisms recognizable to us, multicellular fossils, so not appear until

400 to 500 MYA

How many mass extinctions have there been?

5

Devonian 340 MYA

70%, caused by asteroid impact, rapid climate change (global cooling)

Triassic 200 MYA

75%, caused by increase in greenhouse gases, rapid climate change

About how many species

8.7 million

Cretatious / Tertiary 65 MYA

80% ext rate. Caused by asteroid or comet impact, volcanic activity, climate change

Mass extinction at end of Ordovician period caused loss of

85% species in planet

Ordovician 445 MYA

85%, caused by rapid climate change (global cooling), falling sea levels

Permian 250 MYA

95%, caused by volcanic activity, increase greenhouse gases, rapid climate change

Systematics

A scientific discipline focused on classifying organisms and determining their evolutionary relationships.

Family Hominidae

Ability to walk erectly

Order primates

Adapted to climb trees

Geographic separation with lungless salamanders is called

Allopathic speciation

Adaptive radiation

An evolutionary pattern in which many species evolve from a single ancestral species, adaptations to allow them to survive in different environmental conditions

Bacteria is the most

Ancient domain

Biodiversity hotspots

Areas of the world that contain more types of life than others. Account for over 50% of all plant species and 42% of all animal species

Prokaryotes

Bacteria and Archaea, no nucleus

General background extinction rate level

Btwn 0.1 and 2.0 species lost per million species per year

Domain Eukarya

Cells contain a nucleus and membrane bound organelles

post-zygotic isolation mechanisms

Different species can mate but there are reproductive issues in the offspring. Result in sterile hybrid between the parent species or offspring that lacks fitness to survive

Most general classification

Domain

3 major life groups

Eukarya, bacteria, archaea

Eukaryotes

Eukarya, have nucleus

Mass extinctions are more

Global in nature

Over one million species are in danger of

Going extinct in next few decades

Number one factor of sixth extinction crisis

Human induced climate change caused by increase of greenhouse gases in atmosphere

Genus homo

Large brain, tool use

sympatric speciation

Less common, species become isolated by other factors when territories overlap

Species

Level of biological classification that represents populations that are reproductively compatible

mass extinction

Loss of large number of plant and animal species from many different taxonomic categories in a relatively short period of time

Extinction

Loss of species from the planet

Biological species concept

Most commonly used. Defines a species as one that is sexually reproductively isolated from other species

Ex of post zygotic isolation mechanisms

Mules that come from horse and donkey

Kingdom Animalia

Multicellular organisms that are mobile and ingest food

To be considered as 2 separate species,

Organisms in a population need to be reproductively isolated from each other

punctuated equilibrium model of speciation

Periods of no change are interrupted by events that promote rapid speciation. Species arise regularly over time

Extinction is not just species but can be of an entire

Phyla or class

Class mammalian

Posses hair and mammary glands

Phyla Chordata

Possess a dorsal supporting rod (spine) and nerve cord

Supergroup Opisthokonts

Possessive cells with flagella

prezygotic isolating mechanisms

Present barriers to 2 pops of similar organisms, preventing mating

Major biodiversity on our planet lies in the

Prokaryotic domains

Phylogenetic trees

Provide indication of relatedness of organisms

Speciation

Rate at which new species are formed

Morphological species concept

Separates species based on differences in physical traits, or morphology (form). Difficult to apply to animals that don't meager fossil records

Speciation is a _______ process

Slow

Gradualistic Model of Speciation

Small changes occur periodically in a population until reproductive isolation occurs, supported by Darwin, unsupported by fossil record

Levels of org small to big

Species-populations-biological communities-ecosystem

Lungless salamanders

Start in N California, slowly migrated south and divided into 3 groups and couldn't mate together, south versions changed color and form

Species

Sum of all the populations of similar organisms that are reproductively compatible of interbreeding and producing living offspring

Biodiversity

The number of different species in an area

Taxonomy

The scientific study of how living things are classified

If the rate of species loss exceeds the rate of new speciation,

There's a general loss of biodiversity

Phylogenetic species concept

Traces evolutionary history of organism and its relatedness to other species through its traits. In this model, the study of an organisms traits and location on the evolutionary tree is a better indication of whether it is a unique species than the biological species concept

BYA

billion years ago

Archaea are more closely related to

eukarya than bacteria

MYA

million years ago

Gene flow

movement of alleles from one population to another via mating between populations

Extinction is a _____ process

natural

background extinction rate

normal extinction of various species as a result of changes in local environmental conditions, typically don't result in a large loss of species.