BIOL 221 - Unit 4: Form and Function, Biodiversity, & Ecology

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