Intro Flashcards
How old is the earth and when we’re the first fossils
4.6x10^9
3.5 Ga (1Ga=10^9 years)
The first organisms were heterotrophs or autotrophs?
Heterotrophs
Stromatolites
Earliest fossils: microbial mats made of layers of microorganisms and sediment. Similar to modern stromatolites formed by Cyanobacteria
How did photosynthesis alter earths atmosphere
-oxygen released from photosynthesis into oceans and lakes reacted with dissolved iron and precipitated as iron oxides
-2.7-2.2 Ga gradual accumulation in the atmosphere leading to the great oxidation event
-700Ma ago, marked increase in levels of atmospheric oxygen
What time period approached modern oxygen levels and when
Cambrian (570-510 Ma)
Cyanobacteria
Photosynthetic bacteria
Anoxygenic
Photosynthesis but no oxygen is produced
Protobacteria and chloroflexi
What type of photosynethis do Cyanobacteria undergo
Photo systems 1 and 2
Need sun, water and carbon dioxide, and release oxygen
Consequences of great oxidation event
- Ozone later formed 450 Ma making life possible near water surface and land
- Free oxygen (lethal to some organisms, important selective pressure, possible acceptor of elections in cellular respiration)
- Evolution of eukaryotic cells-2.1Ga ago
Aerobic respiration give more _____ in cellular respiration
ATP
Due to oxygen being a good carrier of electrons
Heterotroph
Dependent on an outside source of organic molecules for its energy.
-animals, fungi, one cell organisms
Autotrophs
Able to make own energy-rich molecules out of simple inorganic materials.
Prokaryotic
Eukaryotic
No nuclear envelope or chromosomes
Nuclear envelopes, complex chromosomes, organelles surrounded by membranes (all but bacteria and archea)
Epidermis and cuticle of plants
Outermost layer of cells, of all above ground portions of the plant involved in photosynthesis. Also epidermis on roots.
Waxy layer preventing water loss
Stomata
Paired with guard epidermal cells around them; is a small opening from the epidermis of a plant.
-open and close in response to environmental and physiological signals to maintain water and gas balance
Annuals
Perennials
Stem differences
Plants with a life span of one year. Stem is photosynthetic organ too
Longer living plants. Stem may become thickened and woody and covered with cork which prevents water loss.
Xylem and phloem
Parts of a plants vascular/ conducting system.
Through which water passes upward through the plant body
Through which food manufactured in the leaves and other photosynthetic parts is transported throughout the plant.
Meristems
Where plant growth originates
Embryonic tissue regions capable of adding cells indefinitely to the plant body.
Types of meristems
Apical-meristems located at the tips of all roots and shoots. Involved with extension of the plant body. (Primary growth)
Lateral-meristems-growth resulting in thickening if stems and roots in secondary growth. Two types of lateral meristems: vascular cambium and cork cambium
During transition to air, plants underwent which adaptation to reproduce?
-production of drought resistant spores
-complex, multicellular structures in which gametes were held and protected from drying out by a layer of sterile cells.
Seed plants
Plants except mosses, ferns and liverworts
Components of the Seed
Embryo, supply of stored food and seed coat
Adaptions to photosynthetic life of land
- Roots to anchor
- Stems to lift up photosynthetic parts
- Leaves for photosynthesis
- Vascular system to transport nutrients
- Reproductive cells protected in coats
Biomes
Natural communities of wide extent, characterized by distinctive, climatically controlled groups of plants and animals.
Determined by precipitation and temperature
Ecosystems
Relatively stable interacting system that involving both living organisms and their environment
-changes at slow rate
-materials are recycled
-energy flows
Importance of sea shores from transition from sea to land colonization
-high concentration of mineral resources carried by lakes, rivers, erosion: needed to make cells! Minerals are scare in ocean, but abundant near shores.
Difficulties of shores for early plants and how they overcame them
-high competition and greater organism density due to light and minerals.
-desiccation
-increased complexity of body structure
-multicellularity, functional integration, tissue specialization: anchoring, photosynthesis, conduction
How is carbon concentration different between land and water
Not, but easier to access on land
Colonization of land by plants was linked to the ability to withstand______
Desiccation
When do easiest plants appear in fossil record
450 mya
Shoots
Stems and leaves
Do all vascular plants have seeds
No
Majority of plants have relationships with ___
Fungi (microrhizy)
Primary producer
Makes organic from inorganic
-plants
How many species of organisms are photosynthetic
Half a million
How do communities come into being
Plants and other photosynthetic organisms are at the base of almost all food chains-primary producers. Therefore the rest of the chain is determined by them.
Plants are determined by soil type, climate, precipitation, seed dispersal
Botany
Study of plants
-previously considered part of medicine
Importance of plants from an anthropocentric view
-food
-drinks
-spices
-medicine
-fuel
-shelter
-paper
-energy
-atmospheric oxygen
-matter (sugars)
Agriculture began when
12-14000 ya
What 6 crops make up 80% of total caloric content
Corn (Zea)
Rice (oryza)
Wheat (Triticum)
Potatoes (Solanum)
Manioc or cassava (Manihot)
Sweet potatoes (Ipomoea)
What additional crops make up most of the remaining 20% of total caloric content
Banana
Sugarcane
Barely
Coconuts
Beans
Sugar beets
Phytoremediation
uses plants to clean up contaminated environments
Plant characteristics (6)
- Multicellular
- Eukaryotes
- Autotrophs
- Cell walls composed of mainly cellulose
- Two adult forms: alternation of generations
6.embryo
Alternation of generations
Sporophytes produce diploid spores that are resistant to desiccation and help in dispersal
Gametophytes produce haploid gametes to interchange genetic information
Plant embryos are protected by what
Tissues of female parent, and they are dependent on them for nutrient acquisition
Why aren’t algae considered plants
Don’t fit multicellular characteristic and plants closest relatives are land plants not water plants
4 main groups of plants
Bryophytes (non vascular plants)
Seedless vascular plants
Gymnosperms
Angiosperms
Bryophytes
-types
-timeline
-characteristics
Mosses, liverworts, hornworts
450-700 mya
Inefficient water transport (diffusion) , close to ground, moist habitats
Seedless vascular plants
-examples
-timeline
-characteristics
Ferns
450-700mya
Specialized tissues for water transportation (efficient) and come in many sizes from herbs to trees
Gymnosperms
-examples
-timeline
-characteristics
Conifers, gnetales
365 mya
No flowers, naked seeds, wood plants
Angiosperms
-examples
-timeline
-characteristics
Flowers
145 mya
Flowers, seeds completely enclosed in maternal tissues, efficient water transportation, convolution with pollinators
