10/3/2014
The Mind‐Boggling Diversity of Life
Protists, Plants, and Fungi
• 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
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10/3/2014
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
– Does not fit into other groups
• Can be mobile using a flagella, cilia, or pseudopodia
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 as an Energy Source?
Protista: The First Eukaryotes
• Live in almost any environment that contains liquid water
• Many protists, such as the algae, are photosynthetic
Protists are Autotrophs, Heterotrophs, or Mixotrophs
• Algae are autotrophic producers that use energy from sunlight to carry out photosynthesis and release oxygen gas as a by‐product
Protists are Autotrophs, Heterotrophs, or Mixotrophs
• Heterotrophic protists rely on other organisms for energy
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10/3/2014
Some Heterotrophs Protists Are Pathogens
• Some of the best‐known protists are disease‐
causing pathogens
– Malaria
‐‐‐ Giardia Protists are Autotrophs, Heterotrophs, or Mixotrophs
• 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
Fungi: A World of Decomposers
Fungi
• The body of a multicellular fungus is called the mycelium and is made up of many mycelial
strands of hyphae
• 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 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?
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10/3/2014
Fungal Parasites
Fungi Can be Dangerous Parasites
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Yeast
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
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
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
Plantae
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10/3/2014
Plantae
• Shared derived trait: Plants are multicellular autotrophs that use specialized organelles called chloroplasts to carry out photosynthesis
Plantae
• Bryophytes – earliest land plants
– mosses, liverwort, and hornwort
• Gymnosperms
– conifers • Angiosperms
– flowering plants
Plantae
• Shared derived trait: cell walls made with cellulose
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: Vascular System
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
• Vascular tissue:
– Phloem
• Transports food molecules like sugar
• Flows down
– Xylem • transports water and dissolved nutrients
• Flows up
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10/3/2014
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
• 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
Female Cone
Plants Are the Basis of Land Ecosystems and Provide Many Valuable Products
• Nearly all organisms on land depend on plants for food
Little Shop of Horrors?!
Angiosperms
Plants
• Plants have value when left in nature as well
– Preventing runoff and erosion
– Recycle carbon dioxide from the atmosphere
– Produce oxygen to breath
White Plant?!
• Ghost plant, where doe it get its energy?
• a non‐
photosynthetic plant that parasitizes mycorrhizal
partners of other plants Monotropa uniflora
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10/3/2014
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? 7