BIOL100 Ch. 14: History of Life

Prokaryotes (review)

Single-celled organisms that have a single loop of DNA, no membrane-enclosed organelles, and are able to reproduce rapidly.

Life is dominated by prokaryotes; bacteria and archaea make up more than 2/3s of the species found on Earth.

Eukaryotes (review)

(2.1 bya fossil records) Include all plants, mammals, and fungi, as well as many single-celled organisms

How old (Approx.) is the Earth?

4.5 billion years old

For roughly how long was Earth without life?

Approx. 1 billion years (As we can tell)

First life on Earth (Stromatolites)

approx. 3.7 billion years ago

Stromatolites

(3.7 Bya) The oldest known fossils formed from many layers of bacteria and sediment. These are evidence of the first cells

Domains

The highest hierarchical level in the organization of life, describing the most basic and ancient divisions among living organisms/ The three domains of life are Bacteria, Archaea, and Eukarya. Of these domains, bacteria were the first to split off from the common ancestor

Bacteria

One of three domains of life, and also one of the five kingdoms of life. The domain and kingdom Bacteria include familiar disease-causing bacteria

Archaea

One of three domains of life (two categories of prokaryotes) and also one of the five kingdoms of life. The domain and kingdom Archaea consist of single-celled organisms. They are well known for their extreme lifestyle.

Eukarya

One of three domains of life, including all the living organisms that do not fit into the domains of Archaea or bacteria, from amoebas to plants to fungi to animals. Eukarya is further divided into three kingdoms: Fungi, Plantae, and Animalia.

Fungi

One of the five kingdoms of life, in the domain Eukarya, is distinguished by its modes of reproduction. Fungi are absorptive heterotrophs

Plantae

One of the five kingdoms of life, in the domain Eukarya, encompassing all plants, which are multicelled photosynthetic autotrophs

Animalia

The animals. One of the five kingdoms of life, in the domain Eukarya, encompasses all animals, including humans, birds, and dinosaurs

Thermophiles

Archaea that thrive in very hot environments, such as volcanic springs.

Halophiles

"salt-loving" archaea that live in environments that have very high salt concentrations

First eukaryotes

2.1 billion years ago

First prokaryotes/early prokaryotes

3.7 bya appears in the fossil record.

Prokaryotic evolution & oxygen production

About 2.8 bya, a group of bacterial prokaryotes evolved a type of photosynthesis that releases oxygen as a byproduct. They at this point, were able to release enough oxygen into the atmosphere to increase the O2 concentration (making it habitable for most of the life we know today)

Biodiversity

The variety of all the world's life-forms, as well as their interactions with each other and the ecosystems they inhabit

Earliest water-dwelling forms of life

Approximately 650 mya, free-floating organisms that needed water to reproduce evolved in the water

Cambrian explosion

The burst of evolutionary activity, occurring about 540 million years ago, resulted in a dramatic increase in the diversity of life. Most of the major living animal groups first appear in the fossil record during this time. (Large predators and well-defended herbivores suddenly appear in the fossil record)

Ordovician Period

First land-dwelling organisms appeared. Early terrestrial colonists were single or few-celled algae-like plants (480 mya),

Fungi made their way to the land next (455-460 mya)

Next, land plants evolved and diversified from the original green algae that made it to land

What adaptation did plants develop during the Ordovician period to retain moisture?

Waxy cuticle

Which group of plants were the first to evolve pollen and seeds?

Gymnosperms

What reproductive structure is associated with gymnosperms?

Pinecones

Which group of plants were the first to evolve flowers?

Angiosperms

Devonian Period

(400 mya) Age of Fishes; by this point, the Earth was covered with plants

At this point, the first land animals also emerged from the aquatic environment. See Amphibians

Amphibians

(365 mya) First vertebrates to colonize the land

They descended from lobe-finned fishes

Late Permian Period

Pangaea formed (230 million years ago)

Reptiles (not dinosaurs) took over as the most common vertebrate group on land

They were the first vertebrates that could reproduce without returning to open water because they laid amniotic eggs - this began the Jurassic Period (Age of the dinosaurs)

Amniotic egg

A shelled, water-retaining egg that enables reptiles, birds, and egg-laying mammals to complete their life cycles on dry land

Evolutionary Tree

A model of evolutionary relationships among groups of organisms that is based on similarities and differences in their DNA, physical features, biochemical characteristics, or some combination of these. It maps the relationships between ancestral groups and their descendants, and it clusters the most closely related groups on neighboring branches.

Node

The point on an evolutionary tree indicates the moment in time when an ancestral group split, or diverged, into two separate lineages. This node represents the most common ancestor of the two lineages in question

Clade

A branch of an evolutionary tree, consisting of an ancestor and all its descendants

Most recent common ancestor

The most immediate ancestor that the two lineages share

Shared derived traits

A unique commonality to all members of a group that originated in the group's most recent common ancestor and was then passed down in the group

Lineage

A single line of descent

Linnean Hierarchy

A system of biological classification devised by the Swedish naturalist Carolus Linnaeus in the 18th century

Species (Review)

members of a group that can mate with one another to produce fertile offspring, or the smallest unit of classification in the Linnean hierarchy

Genus (Plural Genera)

The unit of classification in the Linnaean hierarchy above species and below family

Family

The unit of classification in the Linnaean hierarchy above genus and below order

Order

The unit of classification in the Linnaean hierarchy above family and below class

Phylum

The unit of classification in the Linnaean hierarchy above class and below kingdom

Kingdom

The unit of classification in the Linnaean hierarchy above phylum, below domain; the second-highest hierarchical level in the organization of life. The five kingdoms of life are

Bacteria

Archaea

Plantae

Fungi

Animalia

Memorandum for Linnean Classification System

"Don't Kings Play Chess On Funny Green Squares"

Don't - Domain

Kings - Kingdom

Play - Phylum

Chess - Class

On - Order

Funny - Family

Green - Genus

Squares - Species

Scientific Name

The unique two-word latin name, consisting of the genus and species names, that is assigned to a species in the Linnean hierarchy

Adaptive radiation

The expansion of a group of organisms to take on new ecological roles and to form new species and higher taxonomic groups