Chapter 5,9 &10: Review…How do we get

Bio Diversity

Biodiversity Influenced by

Climate which determines biomes, Diverse Habitat and Natural selection

….species interactions….

Natural Selection • Some individuals may be better suited to

the environment than others.

• Those better able to survive and reproduce leave more offspring. Bird of Paradise

• Their descendants form a larger proportion of the next generation.

Mutation • Genes are inherited from one generation to the next

– Genes made up of DNA• When cells divide

– DNA is reproduced , Each cell gets a copy• If an error occurs in the reproduction of DNA it gets

passed to new cells• DNA change = Mutation

Mutation

The Evolution of Life on Earth

• Earliest fossils 3.5 billion years old– Photosynthetic relative of bacteria– Released large amounts of oxygen into the

atmosphere

Evolution of Life on Earth

Carl Sagan

The Evolution of Life on Earth

• Cambrian Period 600 million years- 500 my– Earliest multicellular organisms

– Shells, gills, filters, efficient guts and circulatory system.

– Life remained in oceans

The Evolution of Life on Earth

• Devonian Period

– 420–360 million years ago

– First animals on land = crossopterygian

– Gave rise to the amphibians

• Still tied to water for reproduction

• Modern species include frogs, toads, newts, limbless water “snakes”

Early Life on Land Innovations for life on land

Structural supportAvoid dessication and UV rays

Means for exchanging gases with airA moist environment for reproduction system

The Evolution of Life on Earth

• Reptiles– Freed from water by evolving a watertight egg– Originate in the Carboniferous (375 mya)– Wide spread by the Jurassic (185 mya)– Two orders of dinosaurs that gave rise to

mammal and birds.

The Evolution of Life on Earth

• Mammals– More capable brain

and faster metabolism

– Placental uterus one key to mammalian success

Human Success

Walking upright

Strong Opposable thumb

Complex brain

That means we can solve problems and work to live more sustainably

Varied Habitat calls for varied forms

Virginia

California

Habitats are dynamic… constantly changing.. Succession

Examples -after a lava flow and at the edge of a receding glacier.

Primary Succession

Where there was no life previously

Secondary succession- from abandoned field to mature forest

Secondary Succession- re-colonization

Dune Succession

• Plants of early succession tend to be– Small, grow well in bright light, and withstand

harshness of environment

• Over time, soils richer, hold more moisture and larger plants can become established– Eastern red cedar, eastern white pine– Beech and maple later on

Succession and Chemical Cycling