Sexual reproduction, genetic material from two parents, emerged as a fundamental evolutionary innovation of eukaryotes. The emergence of sexual reproduction in the Domain Eukaryota highlights the unique properties of eukaryotic cells. Eukaryotes have Complex Cell Structure, chromosomes within a nucleus, meiosis, a special type of cell division that reduces the chromosome number by half and creates genetic […]
Sexual Reproduction Read More »
An example of early live birth is the protomammal Kayentatherium, Jurassic period. This cynodont is related to early mammals and its clutch size suggested egg-laying, providing clues about the transition to live birth. The switch to live birth in mammals, including marsupials and placentals, likely evolved once at their common ancestor, suggesting live birth in mammals
Mammals: First Live Births Read More »
After about 320 million years, the next significant leap in egg evolution came with reptiles, which developed amniotic eggs. These eggs have a protective shell and specialized membranes to support development outside of water, enabling reptiles to lay eggs in terrestrial environments.
Reptile Amniotic Eggs Read More »
The evolution of egg-laying evolved before fish. It is thought to have developed with or shortly after the emergence of the first multicellular animals, around 640 million years ago. Kingdom: Animalia > Phylum: Porifera (sponges) and Cnidaria (jellyfish, corals, etc.)
All life today are either Prokaryote or Eukaryote. Around 2 billion years ago, Eukaryotes evolved from Prokaryotes. The evolutionary leap to eukaryotes introduced cells with a nucleus and membrane-bound organelles, a complex architecture derived from prokaryotic predecessors through endosymbiosis. This process, crucial for eukaryotic evolution, involved the incorporation of prokaryotic cells into the cytoplasm of
The First True Eukaryotes Read More »
Both reptiles and our ancestor synapsids evolved from amphibians. While reptiles evolved better amniotic eggs, synapsid eggs were like amphibian eggs. Synapsid’s birthing process eventually led to mammalian live births. These are the animals that evolved Complex Sentience, the ability to feel various emotions. While it is unknown when this complex spectrum fully evolved, it
Early Complex Sentience Emerges: Dimetrodon Read More »
Morganucodon is an example of a plant eater likely similar to our direct-line ancestors around this time. It is not a direct human ancestor but is among the early mammaliaforms, close to the lineage leading to true mammals. It likely had a varied diet, but its inclusion here highlights the transition towards more specialized mammalian
Morganucodon: An Early Mammalian Herbivore Read More »
Plesiadapis, a proto-primate, is an example of a fruit-insect eater likely similar to our direct-line ancestors around this time. Class: Mammal; Early Primate (Plesiadapiformes) Time Period: Late Paleocene Diet: Likely Frugivorous/Insectivorous
Plesiadapis: First fruit-insect eaters. Read More »
Creatures of this time evolved into fish (us), jellyfish, cephalopods, and arthropods. In the deep waters of the late Precambrian era, the seeds of sentience were sown with the evolution of the earliest common ancestors to later cephalopods and fish. These primordial creatures, equipped with the most basic nervous systems, embarked on the path toward
Presentient Animals Emerge: The Ediacaran Prelude Read More »
First Brains: By about 520 million years ago, hunters roamed the seas. In the Cambrian explosion, a period of rapid evolutionary development that began around 541 million years ago, the earliest known animals with structures recognizable as brains made their debut in the Earth’s oceans. They possessed rudimentary beginnings central nervous systems, including a brain.
Earliest Known Hunter Read More »
The appendix is a small, finger-shaped pouch attached to the large intestine. It has long been considered a vestigial organ, meaning that it has no function in the human body. However, recent research suggests that the appendix may actually serve as a reservoir for beneficial gut bacteria. The appendix is an example of a Phenotype
The millipede Pneumodesmus newmani is the oldest air-breathing animal known to date. This ancient denizen of the Scottish waters once roamed the Earth during the early Silurian era. The millipede likely supplemented its oxygen intake through air as well as using its gills while in water. Kingdom: Animalia > Phylum: Arthropoda > Class: Diplopoda (millipedes)
Oldest Known Air Breather Read More »
First DNA Life: From chemical reactions before 4 billion years ago to replicating molecules about 4 billion years ago to DNA based life then to LUCA, the only DNA based branch to survive. Meaning, DNA based life likely started before LUCA, and LUCA is the only branch to survive the test of time. From LUCA
LUCA: Last Universal Common Ancestor Read More »
Around 1.7 billion years ago, a branch of protozoa, an advanced branch of the eukaryote cells, split into animals, plants, and fungi. These three separate lineages are the ancestors of modern plants, fungi and animals. 1.7 billion years ago: Plants diverge from the common protozoa ancestor. 1.5 billion years ago: Fungi and animal branch emerges.
Animals, Plants, and Fungi Split Read More »
The earliest known vertebrates originated about 530 million years ago during the Cambrian explosion. Domain: Eukaryota > Kingdom: Animalia > Phylum: Chordata
The first land plants appeared during the Ordovician period. Life was diversifying rapidly during the Ordovician period.
Through genetic analyses, scientists now believe the Comb Jellyfish is the earliest known true animal to evolve on Earth. Prior to this genetic analyses, simple sponges were thought to have evolved first. Kingdom: Animalia > Phylum: Ctenophora > Class: Tentaculata
First True Animals – Comb Jellyfish Read More »
Organisms that consist of more than one cell took several billion years to evolve from unicellular organisms. All species of animals, land plants and most fungi are multicellular, as well as many algae. A few organisms are partially both such as slime molds and social amoebae. Domain: Eukaryota > Kingdom: Animalia > Phylum: Porifera (sponges)
First Multicellular Animals Read More »
The earliest known life on Earth are fossilized microorganisms found in hydrothermal vent precipitates. Currently dated to about 3.42 billion BCE. These microorganisms were prokaryote cells. Single celled organisms with no nucleus and had early simple DNA. More complex DNA in a nucleus evolved about 1.5 billion years later in Eukaryotic cells, circa 2 billion
Oldest Known Fossil-Microorganisms Read More »
North America splits from Europe causing diverging evolutionary lines. Over millions of years, the modern-day Europe (Eurasian plate) and North America (North American Plate) separated during the final breakup of Pangaea in the early Cenozoic Era. This split is a later part of that breakup and created the North Atlantic Ocean.
Opening of the North Atlantic Ocean Read More »
