Download - The Mind-Boggling Diversity of Life

The Mind-Boggling Diversity of Life• The Eukarya domain

contains four kingdoms– Protista– Plantae– Fungi– Animalia

• Eukaryotes evolved sometime after prokaryotes populated the Earth

The Dawn of Eukarya• Key evolutionary

features of eukaryotes:

– Presence of a nucleus – Membrane-bound

internal compartments– Larger cell size– Sexual reproduction– Multicellular (not all are

though)

Eukaryotes Have Subcellular Compartmentalization and Larger Cells

• Eukaryotic DNA is in a nucleus

• Increased complexity allows eukaryotes to function with greater efficiency

• Eukaryotes are thousands of times larger in volume than prokaryotes

Sexual Reproduction Increases Genetic Diversity

• Sexual reproduction increases genetic diversity by producing offspring that are different from each other and from both parents.

Protista: The First Eukaryotes


• The protists include any organism that do not fit into the other kingdom classifications

• Shared Derived Traits:– Simple organization – No specialized tissues

• Can be mobile using a flagella, cilia, or pseudopodia


• Live in almost any environment that contains liquid water

• Many protists, such as the algae, are photosynthetic

Protists are Autotrophs, Heterotrophs, or Mixotrophs

• What is an autotroph? What is a producer?

• What is an heterotroph? What is a consumer?

• What is an mixotrophs?


• Algae are autotrophic producers that use energy from sunlight to carry out photosynthesis and release oxygen gas as a by-product

Algae as an Energy Source?


• Heterotrophic protists rely on other organisms for energy

Some Heterotrophs Protists Are Pathogens

• Some of the best-known protists are disease-causing pathogens– Malaria ---

Giardia


• Mixotrophs obtain energy from a variety of sources, depending on environmental conditions– Photosynthesize– Consumer

• W2L: How is this adventitious for the mixotroph?

Euglena viridis

Fungi: A World of Decomposers

Fungi• Shared derived trait:

Fungal cells have a protective cell wall that produce chitin to protect the cell and give the fungus structure

• Fungi can be multicellular or single-celled species

• DNA comparisons show that fungi are more closely related to humans than to plants!

Fungi• The body of a

multicellular fungus is called the mycelium and is made up of many mycelial strands of hyphae

Fungi Play a Key Role as Decomposers

• Fungi are heterotrophs that decompose organic materials

• Fungi are the most important decomposers on land

• W2L: What do you think would happen if there were no more fungus in the world?

Fungi Can be Dangerous Parasites

• Parasitic fungi decomposes the tissue of living organisms

Athlete's Foot Ring “worm”

Zygomycosis

Yeast

Fungal Parasites• The carpenter ant

(genus Campanotus) is infected by a parasitic fungi of the genus Cordyceps, which changes the behavior of their host

• spores attach to the surface of the ant and enter the ant’s body

• mycelia grow inside the ant’s body absorbing soft tissues but avoid vital organs

• When the fungus is ready to reproduce, the mycelia grow into the ant’s brain!

• The fungus produces chemicals in the brain causing the ant to climb to the top of a plant and latch on

• The fungus then devours the ant’s brain, killing the host releasing clusters of spores into the air completing the life cycle of the fungus

http://uts.cc.utexas.edu/~gilbert/

Lichens and Mycorrhizae: Collaborations between Kingdoms

• Symbiosis is the process of two organisms working together in close association

• Fungi have formed beneficial relationships with members of almost every kingdom

Lichens Contain a Fungus and a Photosynthetic Microbe

• A lichen is a positive association between:– a photosynthetic

microbe (algae or cyanobacteria) and a fungus

• Lichens are pioneers of barren environments, helping to facilitate soil formation

Mycorrhizae are Beneficial Associations Between a Fungus and a Plant’s Root

• Mycorrhizae are beneficial associations between a fungus and the plant root

• Plant gets more water with Mycorrhizae

• Mycorrhizae gets sugars from plant

Plantae

Plantae• Shared derived trait: Plants are multicellular

autotrophs that use specialized organelles called chloroplasts to carry out photosynthesis

Plantae• Shared derived trait: cell walls made with

cellulose

Plantae

• Bryophytes – earliest land

plants– mosses, liverwort,

and hornwort• Gymnosperms– conifers

• Angiosperms– flowering plants

Plants Had to Adapt to Life on Land

• In order to evolve on land, plants developed a waxy cuticle that prevents them from drying out

Plants Had to Adapt to Life on Land

• Stomata are pores that open and close to allow the carbon dioxide needed for photosynthesis to enter the leaves

Plants: Vascular System

• Vascular tissue:– Phloem• Transports food

molecules like sugar• Flows down

– Xylem • transports water and

dissolved nutrients• Flows up

Gymnosperms• Gymnosperms were the first plants to

evolve pollen and seeds– The evolution of seeds contributed

to their success• Pollen – contains sperm cells– dry and powdery– produced in great quantities

• Seed – plant embryo and a short

supply of food encased in a protective seed coat

Male Cone

Female Cone

Angiosperms

• Angiosperms produce flowers and fruit

• Most abundant and diverse group of plants

• Contain both male and female structures

• Bright petals, odors, and sugary nectar are used to attract pollinators

Plants Are the Basis of Land Ecosystems and Provide Many Valuable Products

• Nearly all organisms on land depend on plants for food

Plants• Plants have value when left in nature as well– Preventing runoff and erosion– Recycle carbon dioxide from the atmosphere– Produce oxygen to breath

Little Shop of Horrors?!

White Plant?!• Ghost plant, where

doe it get its energy?

Monotropa uniflora

• a non-photosynthetic plant that parasitizes mycorrhizal partners of other plants

Biology is a little Messy• What is one of the main

shared derived traits of plants?

W2L: How can you explain the Ghost Plant then? Is it technically not a plant?

Cool Thought!

• What if there were plants on another planet?