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functions of roots
anchorage
absorption
conduction
storage
What are the two MOST IMPORTANT functions of roots?
anchorage
absorption
What does meristematic tissue contain
meristems
What does vascular tissue include?
Xylem and phloem
What does a root’s high surface area to volume ratio facilitate?
absorption of water and nutrients
morphological diversity of roots
taproot system
fibrous root system
taproot system description
taproot is a large vertical main root of a plant’s root system; grows directly downward
Where is taproot formed?
formed from a strongly developed taproot and its branches
What can arise from taproot?
lateral roots
branch roots
Where is the fibrous root system found?
Found in monocots
How does the fibrous root system develop?
main root system develops from roots that arise from the stem (adventitious roots)
Fibrous root system definition
system in which no one root is more prominent than the others, primary root usually short lived
Which type of root system is better at preventing erosion?
Fibrous root system
Which type of root system tends to be better at accessing water and nutrients in more shallow soil?
Fibrous root system
Which type of root system tend to be better at accessing water and nutrients in deeper soil?
taproot system
niche partitioning in root systems
differences in rooting depth minimize competition for water and nutrients in grassland species
root system phenotypic plasticity
the structure of the root system can vary depending on environmental conditions
waterlogged soils leads to…
shallower roots
dry soils lead to…
deeper roots
patches of nutrient-rich soils lead to…
more roots
root morphology
root cap
root hairs
functions of the root cap
protects the apical meristem
sense gravity and determine the direction of growth
synthesizes and secretes a slimy substance that reduces friction as root moves through soil
What are root hairs? (cell-wise)
epidermal cells
What is the function of root hairs?
absorption of water and nutrients
Do root hairs have a high surface area to volume ratio?
yes
examples of modified roots
photosynthetic roots
penumatophores
proproots
anchorroots
storage roots
photosynthetic root function + biome
photosynthesis; tropical rain forest, swamp
pneumatophores function + biome
gas exchange; wetlands, swamps, mangrove forests
prop roots function + biome
stabilization; tropical rain forest, mangrove forests
anchor to trees; tropical rainforest, temperate deciduous forest
anchor roots function + biome
storage roots function + biome
store carbohydrates; shrubland, grasslands, savannah
morphological diversity in shoot system
variation in size and shape allows plants of different species to harvest light at different locations, which reduces competition
phenotypic plasticity in shoot system
the size and shape (form) of an individual’s shoot system can vary based on growing conditions
functions of stems
support
conduction
generate new tissue
storage
TWO MAIN functions of stems
support
conduction
plant growth
plants can grow throughout their lives; they have indeterminate growth
what are meristems?
populations of undifferentiated cells that retain the ability to undergo mitosis
what do meristems contribute to?
primary and secondary growth of plants
primary growth
increase in length of shoots and roots
apical meristems are located at the tips shoots and roots
secondary growth
increase in width (girth) of shoots (and some roots)
lateral meristems (cambia) form cylinders made up of a single layer of meristematic cells
what are the functions of bark?
inner bark (secondary phloem) - conduction of sugar
outer bark - protection from pathogens, prevent water loss
protection from fire
What are the functions of wood (secondary xylem)?
conduction of water (sapwood)
structural support (heartwood)
A tree will die if the bark is stripped off around the entire circumference of the tree. Why?
Phloem cells are removed, sugars can no longer be transported from the leaves to the roots, and the roots will die.
examples of modified stems
succulent stem
stolons
rhizome
tuber
thorns
succulent stem function + biome
water storage; desert
stolons function + biome
asexual reproduction; temperate deciduous forest, grassland
rhizome function + biome
asexual reproduction, storage; shrubland, grassland, savanna, temperate deciduous forest
tuber function + biome
carbohydrates storage; shrubland, grassland
thorns function + biome
defense; savanna, temperate deciduous forest, thorn forest
Main functions of leaves
photosynthesis
relatively high surface area to volume ratio facilitates absorption of light
morphological diversity in leaves
simple leaf
compound leaf
doubly compound leaf
needlelike leaf
alternate
opposite
whorled
rosette
Which leaf type is more common in drier biomes? Why?
Needlelike leaf, because thin leaves help to reduce water loss and more resistant to high winds
phenotypic plasticity in leaves
the shape or form of a leaf can vary among leaves on an individual plant or among individuals throughout the range of a species in response to changes in environmental conditions
shade leaf
larger surface area
thinner
sun leaf
smaller surface area
thicker
What are the functions of epidermal cells in leaves?
protection
reduce water loss
secrete cuticle
What are the functions of trichomes in leaves?
deter herbivores
trap insects
reflect sunlight
reduce water loss
examples of modified leaves
succulent
tendril
bracts
traps
spines
succulent functions + biomes
water storage; desert
tendril functions + biome
climbing; temperate deciduous forest, temperate coniferous forest, shrublands
bracts function + biome
attract pollinators; temperate deciduous forest, tropical rain forest
traps function + biome
carnivory; wetlands, tropical rainforest
spines function + biome
defense; desert
importance of animals
provide resources for humans
provide assistance to humans
pollination
transmit diseases
How do animals provide resources for humans?
food
materials
transportation & power
medical value
pharmaceuticals
How do animals provide assistance to humans?
guide dogs
detection (sniffer) dogs
characteristics of animals
multicellular eukaryotes
cells with an extracellular matrix (ECM), which includes proteins specialized for cell-cell adhesion and communication
heterotrophs; obtain carbon from organic compounds produced by other organisms
movement, at some point in their life cycle
All animals except ______ have nerve cells (neurons) and muscle cells
sponges
What characteristic is shared by all animals and distinguishes them from choanoflagellates?
multicellularity
What are the consequences of multicellularity?
cell specialization - more efficient functioning through division of labor
individual organism can grow larger (gather more resources, store extra food, produce more surviving offspring, evade predators)
diploblasts
embryos have two types of tissue
triploblasts
embryos have three types of tissue
types of embryonic tissue layers
ectoderm
endoderm
mesoderm
ectoderm
gives rise to the skin and the nervous system
endoderm
gives rise to the lining of the digestive tract and organs that connect to the digestive tract
mesoderm
gives rise to the circulatory system, muscle, and internal structures such as bone and most organs
muscle in animals
all animals share homologous genes for contractile proteins, such as actin and myosin
in ctenophores and cnidarians, contractile cells are derived from endoderm and/or ectoderm (epitheliomuscular) cells - functionally similar to true mesodermal muscle cells
What is the consequence of muscle?
animals are able to move on their own
What type of symmetry do ctenophores, many cnidarians, and some sponges have?
Radial symmetry
What type of symmetry do all other animals have?
Bilateral symmetry
What are the consequences of radial symmetry?
greater access to environment
more likely to encounter prey and other aspects of the environment in any direction
What are the consequences of bilateral symmetry?
encounter prey and other aspects of the environment at the leading end
efficient locomotion
nervous system in animals
neurons transmit and process information in the form of electrical signals
cephalization in animals
evolution of a head, or anterior region, where structures for feeding, sensing the environment, and processing information are concentrated
What are the consequences of a body plan with cephalization and a central nervous system?
rapid, directed movement and hunting
coelom
fluid-filled cavity that is completely lined with mesoderm tissue
ceolomates
enclosed body cavity completely lined with mesoderm
acoelomates
no enclosed body cavity
pseudocoelomates
enclosed body cavity partially lined with mesoderm
What are the consequences of a coelom?
space for the circulation of oxygen and nutrients
enables internal organs to move independently of each other and independently of the inner and outer tubes
What characteristic do annelids, arthropods, and chordates all have, which evolved independently in each group?
segmentation
segmentation in animals
division of the body or a part of the body into a series of similar structures
What is the consequence of segmentation?
enables specialization
diversification of animals
evolution of animals has resulted in a variety of ways in which animals perform the functions necessary for survival and reproduction
diversity of characteristics allow animals to survive and reproduce in a variety of habitats
sensory organs
sight: light is stimulus
hearing: sound is stimulus
olfaction: molecules are stimulus
taste: molecules are stimulus
touch: contact, pressure are stimuli
thermal energy: aids in finding prey
magnetic fields: aids in navigation
electric fields: aids in detecting prey
barometric pressure: aids in avoiding storms
gravity: aids in movement in aquatic environments
diversification of animals
ecological roles (based on what animals eat)
detritivores: feed on dead organic matter
herbivores: feed on plants and algae
carnivores: feed on animals
omnivores: feed on a combination of plants, animals, fungi, protists, archaea, and/or bacteria
diversification of animals
feeding strategies (based on how animals eat)
suspension (filter) feeders: capture food by filtering put particles floating in water or the air
deposit feeders: ingest organic material that has been deposited within a substrate or on its surface
fluid feeders: suck or mop up liquids such as nectar, plant sap, blood, or fruit juice
mass feeders: take chunks of food into their mouths
non-bilaterian animal lineages
porifera
ctenophora
cnidaria
porifera (sponges)
symmetry
habitat
example organism(s)
distinguishing chracteristics
asymmetrical; a few radial
marine and freshwater biomes
sponges
spicules; lack true tissues, nerves, and muscles
ctenophora (comb jellies)
symmetry
habitat
example organism(s)
distinguishing chracteristic(s)
radial
marine biomes
comb jellies
gelatinous bodies with comb-like rows of cilia, coloblasts, diploblastic
