Life Invaded the Land Chapter 12, Section 3 Biology Mrs. James

Formation of the Ozone Layer Early life could only survive in water because the earth lacked an ozone layer 2.5 billion years ago O2 was being added to the earth by what organism ?

Plants and Fungi on Land The 1 st organisms to live on land were: –Plants –Fungi Plants evolved from photosynthetic protists Plants & fungi needed each other to survive

Plants and Fungi on Land Mycorrhizae – biological partnerships between plants & fungi Mutualism – a relationship between 2 species in which both species benefit –The fungus provides minerals to the plant –The plants provides nutrients to the fungus

Arthropods The 1 st animals to invade the land were arthropods Arthropod – an animal with a hard outer skeleton, a segmented body, and paired, jointed limbs –Lobsters, crabs, insects & spiders

Arthropods Insects –Evolved from the 1 st land dwellers –Most plentiful & diverse group –Success is connected to having wings & flying –Led to partnership of insects & flowering plants –Oldest fossil of flowering plant is 127 million years old

Vertebrates - Fishes Vertebrates – an animal with a backbone Fish were the 1 st vertebrate –Jawless fish – 530 million years ago –Jawed fish – 430 million years ago –Changes in fish eventually made them capable of living on the land

Vertebrates - Amphibians The 1 st land vertebrates inhabited the land 370 million years ago They were amphibians: –Have lungs –Had limbs (derived from fins)

Vertebrates - Reptiles Reptiles evolved from amphibians –340 million years ago –Better than amphibians –Dry, water-tight skin –Water-tight eggs

Vertebrates – Mammals & Birds Birds evolved from feathered dinosaurs After the mass extinction 65 million years ago, the make- up of the earth changed Birds & mammals became dominant animals

Vertebrates – Birds & Mammals Important roles in evolution –Extinction –Continental drift Continental drift – movement of earth’s land masses in the present-day position of the continents

Any Questions? There are more dates to add to your timeline Timelines are due the Monday after spring break Worth – 25 points if you have all dates & a description of what happened then in a timeline format Extra credit – up to 7 points for illustrations for each date (hand drawn or printed off the computer)