Diversity of Life

Chapter 4, Section 3

Evolution overview

• All life on earth began about 3.5 billion years ago with organisms that were a single cell

• Then one billion years ago organisms that are made of many cells appeared as a result of evolution

• During evolution traits that do not help organisms survive disappear while good traits that help with survival remain

Classification

• As a result of evolution earth is populated by many different organisms with different traits.

• We group these organisms according to their similar characteristics

• Classification – grouping and naming of organisms according to their evolutionary relationships and shared characteristics

Tree of Life

Organisms are classified into based on:

1.Cell Typea. Prokaryotes

b. Eukaryotes

Prokaryotic Cell Eukaryotic Cell

2. Number of Cellsa. Unicellularb. Multi-cellular

Unicellular

Multicellular

3. Cell Structure

4. Mode of Nutritiona.Autotrophs- Chemoautotrophs - Photoautotrophs

b.Heterotrophs

3 Domains of Life • Domain Bacteria

–Eubacteria• Domain Archae

–Archaebacteria• Domain Eukarya

–Protists, Fungi, Plantae, Animalia

Three Domain System    

Domain Eukarya - includes organisms composed of eukaryotic cells (plants, animals, fungi, protists – 4 kingdoms)

Domain Bacteria - includes all prokaryotic cells from Kingdom Eubacteria

Domain Archaea – prokaryotic cells, includes only "ancient" bacteria, Archaebacteria (1 kingdom)

6 Kingdoms of Life

• Archaebacteria

• Eubacteria• Protist

• Fungi• Plant• Animal

Kingdom Fungae

•Multicellular (most), some unicellular (baker's

yeast)

•Heterotrophic (mainly decomposers)

•Eukaryotic

Photos by

nutmeg66

FungiPlay an important role in breaking down the bodies of dead organisms.

Recycle matter, nutrients

Fungi are not the only decomposers (worms, bacteria)

No decomposers = no life = no cycling of materials = organisms won't have the building blocks to grow and reproduce

Kingdom Protista

•Most are unicellular

•Can be heterotrophic (Ameba) or autotrophic

(Algae)

•Eukaryotes (all have nucleus)

•Most live in water

Photo of Ameba by PROYECTO

AGUA **/** WATER PROJECT

Kingdom Eubacteria & Kingdom

Archaebacteria

•Unicellular

•Can be autotrophic or heterotrophic

•Prokaryotes (do not have a nucleus)Eubacteria = common bacteria

(E. coli, Salmonella)

Archaebacteria = “ancient

bacteria”, exist in extreme

environments

Archaea and Bacteria

• Archaea differ from bacteria in their genetics and the makeup of their cell wall.

• Bacteria are microscopic, unicellular organisms that usually have a cell wall and reproduce by cell division.

• Unlike all other organisms, bacteria and archaea lack nuclei.

• Bacteria and archaea live in every habitat on Earth, from hot springs to the bodies of animals.

Bacteria and the Environment• Some kinds of bacteria break down the remains

and wastes of other organisms and return the nutrients to the soil.

• Others recycle nutrients, such as nitrogen and phosphorus.

• Certain bacteria can convert nitrogen from the air into a form that plants can use. This conversion is important because nitrogen is the main component of proteins and genetic material.

Bacteria and the Environment

• Bacteria also allow many organisms, including humans, to extract certain nutrients from their food.

• The bacterium, Escherichia coli or E. coli, is found in the intestines of humans and other animals and helps digest food and release vitamins that humans need.

Kingdom Plantae

•Multicellular

•Autotrophic

•Eukaryotic

•Cannot move

(due to cell walls)

Plants

• Mosses – example of plants with no vascular tissue (can not transport water inside the plant) – live near water or in humid areas, can't grow tall

• Vascular Plants – transport water fro roots all the way to the top of the plant – can grow tall, no need to be near water

Vascular Plants

• Gymnosperms – cone bearing plants – naked seed – seeds are not enclosed

• Angiosperms – flowering plants – greatest number of plants on Earth – seeds are enclosed in a ........ fruit; flower serves to attract pollinators

Kingdom Animalia

•Multicellular

•Heterotrophic

•Most can move

•Examples: birds,

insects, worms,

mammals, reptiles,

humans, anemones

Photo by Eduardo Amorim

Photo by Tambako the

Jaguar

Animals

• Invertebrates are animals that do not have backbones (insects, squid, horseshoe crab).

• Vertebrates are animals that have a backbone, and includes mammals, birds, reptiles, amphibians, and fish. Only Birds and mammals are warm-blooded.