1
Q
Are fungi multicellular or unicellular? Heterotrophic or autotrophic?
A
- Unicellular AND multicellular
- Heterotrophic
2
Q
How do fungi acquire food?
A
By absorbing dissolved molecules
3
Q
What role do fungi play in ecological systems?
A
Main decomposers
4
Q
Can fungi be deadly?
A
Yes, they can be deadly pathogens
5
Q
What kingdom may have driven evolution to land?
A
Fungi
6
Q
What are some similarities that fungi have with plants?
A
- Many grow “rooted” in the ground
- Cells have cell walls and vacuoles
- Sexual and/or asexual reproduction
- Some make spores like basal plant groups
- Many species produce a fruiting body to aid in reproduction
7
Q
What are some similarities that fungi have with animals?
A
- Heterotrophic and lack chloroplasts
- Produce chitin
- Store carbohydrate energy as glycogen
- Produce vitamin D when exposed to sunlight
- Genetic similarities
8
Q
What are some unique features of fungi?
A
- Reproducing via clonal budding or binary fission
- Cells grow as hyphae
9
Q
What are hyphae? How does their growth occur?
A
- Cells in most multicellular fungi grow as elongated filamentous structures (called hyphae)
- Hyphal elongation occurs at the tips
- Tip growth occurs by the extension of cell walls through the external polymerization of cell wall components and the internal synthesis of new cell membranes
10
Q
What are the 9 parts of a hyphae?
A
- Hyphal wall
- Septum
- Mitochondrion
- Vacuole
- Ergosteral crystal
- Ribosome
- Nucleus
- Endoplasmic reticulum
- Lipid body
11
Q
What is the common ancestor that fungi and animals share?
A
A flagellated protist
12
Q
What kind of fungi retain their flagellum? What are they most genetically similar to? When did they first branch?
A
- Basal fungi like chytrids
- Protists
- 1-1.5 billion years ago
13
Q
What are the different ways taxa are distinguished?
A
- Based on morpholgy, such as size and shape of spores or fruiting structures
- Could also be based on genetic similarity, or their biochemical and physiological characteristics, such as their ability to metabolize certain biochemicals
14
Q
What are the 6 different types of fungi?
A
- Chytrid fungi
- Anaerobic fungi
- Zygote fungi (or zygomycetes)
- Root symbiotic fungi
- Sac fungi
- Club fungi
15
Q
Which types of fungi are often referred to as “higher fungi”
A
Sac fungi and club fungi
16
Q
Which types of fungi are mostly unicellular?
A
Chytrid fungi and anaerobic fungi
17
Q
What is chytrid fungi?
- What is their structure like?
- Where do they live?
- How do they reproduce?
- What do they breakdown?
A
One of the earliest diverging fungal lineages
- Microscopic with a flagellum
- Aquatic, can live in wet conditions
- Mostly asexual reproduction occurs through the release of zoospores, derived through mitosis
- Breakdowns cellular strengthening materials such as chitin and kertain
Sometimes act as parasites
18
Q
What is anaerobic fungi?
- Where is it found?
- What was it first thought to be?
- What is its structure like?
- How does it reproduce?
- What does it breakdown?
A
- Found in the digestive tract of many herbivores
- First thought to be a chytrid
- Microspic with a flagellum
- Asexual reproduction
- Breaks down cellular strengthening materials, such as cellulose, aids in the digestion of plant material
19
Q
What is zygote fungi?
- What are they commonly referred to as?
- Where are they found?
- How do they reproduce?
- How does this change when environmental conditions degrade?
- Are they parasites? Of what?
A
- Mold or mycorrhizal fungi
- Mostly terrestrial, in soil or on decaying matter
- Typically reproduce asexually using sporangiospores
- They switch to sexual reproduction by fusing mating strains into a zygospore
- Some are parasites of plants, insects, and small animals
20
Q
What is root symbiotic fungi?
- Where is it found?
- How does it reproduce?
- What does it produce?
A
A form of mycorrhizal fungi
- Mostly terrestrial, in soil
- Asexually, produces glomerospores, and cannot survive without the roots of plants
- Produce arbuscular mycorrhizae, a form of hyphae that interacts with the root cells of plants.
21
Q
What is sac fungi?
- What is its defining feature?
- How does it reproduce?
A
The largest phylum of fungi
- The ascus, a microscopic sexual structure where spores form
- Also reproduces asexually
Ranges from molds to mildews to yeast to mushrooms
Also the fungal symbionts in the majority of lichens
22
Q
What is club fungi? How does it reproduce?
A
- Contains true mushrooms but also puffballs, stinkhorns, bracket fungi, earth stars, smuts, bunts, rusts, some yeasts
- Reproduce sexually via the formation of specialized club-shaped end cells called basidia
23
Q
How can you tell fungi apart?
A
By looking for the structure types commonly used for sexual reproduction
24
Q
What are some features of multicellular fungi?
A
- Possess hyphae that can collate into a mycelium
- Fruiting bodies sprout above the ground
- Most of the non-yeast zygote, root symbiotic, sac, and club fungi
25
What is the largest whole fungus? How old is it? What is the largest individual mushroom?
- The largest whole fungus belongs to *Armillaria ostoyae*, which covers 9 km^2 in an Oregon State Park, it is estimated to be 2400 years old
- The largest individual mushroom belongs to *Phellinus ellipsoideus* and can weigh 500kg
26
How do fungi digest food? What are their three nutritional modes?
- Fungi find food, secrete digestive enzymes (called exoenzymes) to digest the food, and then absorb the smaller food molecules
1. Parasitic
2. Mutualistic
3. Saprophytic
27
What are saprophytes?
- Decomposers that feed on waste/dead organic matter
- A critical role in nutrient cycling in nature
- Resets the food web and allows for nutrients to move
28
What is the mycorrhizal network?
An underground network found in forests (and other plant communities) created by the hyphae of fungi joining with plant roots.
29
What can fungi form mutualistic relationships with? What is an example?
- Fungi form mutualistic relationships with plants, algae, cyanobacteria, and animals
- Ex. lichens (symbiotic partnership between a fungus and an alga or cyanobacteria)
30
31
What do pathogenic and parasitic fungi do?
- Form a type of symbiotic relationship with other living organisms
- They benefit to the detriment of their host
- Many species affect trees and other plants, or other types of mushrooms, and even animals
- Some parasitic fungi form mushrooms, while many do not.
32
What are some examples of fungi as pathogens and parasites?
- Corn smut: a crop disease
- Pine needle rust: a plant disease
- White nose syndrome: digests keratin and has crashed bat populations
33
How has fungi driven evolution on land?
- Would have evolved from aquatic algae, but the transition to land would be a challenge
- Proto plants lacked roots
- Fungi can dissolve rocks to extract minerals, a process called biological weathering
- Mutual symbiosis formed, plants got nutrients and fungi got carbs
- 90% of all plants still have fungal partners
34
Are plants prokaryotes or eukaryotes?
Are they multicellular or unicellular?
How do they get their nutrition?
About how many known species of plants are there?
How many of these produce seeds?
- Eukaryotes
- Mostly multcellular, except for some (e.g. green algae)
- Predominantly photosynthetic
- ~380000, ~260000 produce seeds
35
What are the major plant groups? What are some examples of each?
- Non-vascular plants
Bryphotes
Green algae
- Vascular plants
Seedless: Lycophytes and pterophytes
Seed plants: Gymnosperms and angiosperms
36
What are the differences between vascular plants and nonvascular plants?
- Vascular plants have **material transport system** for water and food; nonvascular plants do not
- Vascular plants have **roots**, nonvascular plants have **rhizoids**
- Nonvascular plants are usually in damp conditions and are often smaller
- Most nonvascular plants reproduce **asexually** by **spores** or vegetative propagating (budding), most vasucular plants reproduce **sexually and form seeds**
37
What are organs in plants?
- Two or more types of tissues that perform a functions
- Roots, stems, leaves
38
What are tissues in plants?
- Groups of cells that together perform a particular function
- Dermal, vascular, ground
39
What are cells in plants?
- Parenchyma cells, collenchyma cells, schlerenchyma cells, water-conducting cells of the xylem, sugar conducting cells of the phloem
40
How do nonvascular plants reflect their early evolutionary history?
By direct diffusion of material and rhizoids
41
How do vascular plants reflect their evolutionary history?
- They use roots, stems, and leaves to draw resources from the ground (water and minerals) and aboveground (CO2 and light)
- These organs form a root system and a shoot system (stems and leaves)
42
What do roots do?
- Anchor a vascular plant in the soil
- Absorb minerals and water
- Require carbohydrates from stem, can store starches
43
What is the primary root called? Where does it originate?
The radicle
- Originates in the embryo
- The first root to emerge from a germinating seed
- Branches to form lateral roots
44
What are the two primary types of root system?
- Taproot system
- Fibrous root system
45
What is the taproot system?
Consists of one main vertical root (taproot: prevents plant from toppling over) and lateral roots (carry out most of the absorption
46
What is the fibrous root system?
Consists of many smaller roots emerging from the stem (no tap root); primary root (the radicle) dies and is replaced
47
What are the pros and cons to the taproot system?
CON: More costly to produce
PRO: Allows for increased height (access to more light) and energy storage (starches)
48
What are the pros and cons of the fibrous root system?
CON: Reduced growth height
PRO: Easier to grow, but more difficult to be uprooted and killed by grazine animals
49
What are the 4 kinds of specialized roots? What does each do?
**Prop Roots**: Stabilize plants in loose soils or when they are too large
**Aerial Roots:** Plants germinate in forest canopy, roots grow down
**Pneumatophores Roots:** Air roots lets plants access oxygen when submerged
**Green Roots:** Photosynthetic aerial roots, for plants that grow above ground
50
What are stems? What do they require?
- Requires water and minerals from roots
- Raised and seperate leaves; exposing them to sunlight
- Raised reproductive structures, facilitating dispersal of pollen and fruit
51
Stems consist of an alternating system of what?
- Nodes (points at which leaves are attached)
- Internodes (stem segments between nodes)
52
What is the apical bud? What is the axillary bud?
- Apical: Location where shoot growth occurs
- Axillary: Precursor of a branch or lateral shoot at the junction between the stem and a leaf
53
What are three specialized underground stems?
- **Bulb:** An underground plant stem that sends out roots and shoots
- **Stolon/Rhizome:** Stems that grow at the soil surface (stolon) or below (rhizome) that form roots at the nodes
- **Tubers:** Enlarged ends of rhizomes or stolon specialized for storing carbohydrates
54
What are leaves? What do they consist of?
- The main photosynthetic organ
They consist of:
- A flattened lamina (blade) with specialized cells that contain chloroplasts for phosynthesis
- A petiole: stalk that attaches the leaf blade to the stem at the node (missing in some, like grass)
55
What are compound leaves?
Leaves with many leaflets attached to the petiole via a petiolule
56
What are the four basic structures of a flower?
- Sepals: modified leaves that help enclose and protect a flower bud before it opens
- Petals: modified leaves: often colourful
- Stamens: pollen producing reproductive organs
- Carpels: ovule-producing reproductive organs
57
What are sepals?
What are they called collectively?
What is their purpose?
- Collectively called the calyx
- Form the outermost part of the flower
- Cover/protect the flower in bud
- Often the most "leaf-like" of the flower parts
- May be photosynthetic
58
What are petals?
What are they called collectively?
What is their purpose?
- Collectively called the coralla
- Act as a lure to attract pollinators
- Colourful, including human visual range and UV colouration
- Nectaries
59
What are stamens?
- The androecium ("male reproductive part")
- Each composed of a **filament** that holds up a capsule-like structure called an **anther**
- Pollen grains (the immature male gametes) develop within the anther
60
What are carpels? What are the three parts and their functions?
- The gynoecium ("female reproductive part")
- **Ovary:** sac-like structure that contains one or more ovules where female gametes develop
- **Style:** long, slender neck or carpel where ovary is located
- **Stigma:** sticky, moist tip which receive pollen
61
What are cotyledons?
- Embryonic leaf (or leaves) in seed-bearing plants
- Provide the nutrition needed for the embryonic plant to germinate and become established as a photosynthetic organism
62
What are monocots? Eudicots?
Monocots - one cotyledon
Eudicots - two cotyledon
63
What is dermal tissue in plants? What does it do? What is it comprised of?
- Tissue that covers and protects the surface of the plant
- It protects plant from damage, **prevents water loss**, and regulates gas exchange
- Comprised of thin epidermis, waxy cuticle, and specialized guard around stoma or cork cells
64
What are vascular tissues? What do they do? What are the two types?
- Transports food, water, hormones and minerals between roots and shoots
- Provides structural support
Two types:
- Xylem (water and minerals)
- Phloem (photosynthesis products)
65
- What does the xylem do?
- What direction?
- Where does it take place?
- Transports water and minerals
- One way (upward) flow
- Hollow dead cells
- Transport is bulk flow due to negative pressure
- No end walls
- Form center of the vascular bundle
- Rich in lignin, which supports the plant
66
- What does the phloem do?
- What direction?
- Where does it take place?
- Transports food in the form of sugars
- Two-way flow
- Live cells with no nucleus
- Transport is by osmosis/turgor pressure
- Perforated end walls
- Outside edge of vascular bundle
- Also transports amino acids, mRNA, and hormones
67
What are ground tissues? What are three main types?
Majority of the plant body
- Parenchyma: filler tissue, spongy
- Collenchyma: growing support, high in cellulose
- Schlerenchyma: main support, high in lignin; dies after it matures
68
What is pith?
Ground tissue that is internal to vascular tissue
69
What is cortex?
Ground tissue that is external to vascular tissue
70
What are parenchymal cells?
- **Comprises the filler or flesh of most of the plant**
- **Contain chloroplasts**
- Forms the cortex in roots, the pith and cortex in stems, the mesophyll of leaves, the pulp of fruits
- Intracellular space, spongy feel
Functions:
- Living cell that perform most metabolic functions (ex. most photosynthesis occurs in these cells)
- Can store starch in stems and roots
71
What are collenchymal cells?
**Provide structural support in growing stems and leaves**
- Elongated cells with thick primary cell walls
- Often found under the epidermis or the outer layer of cells in young stems and in leaf veins
Function:
- Living polyhedral cells that support young parts of the plant shoot (elongate with the stems and leaves as they grow)
- Affected by mechanical stress
72
What are sclerenchymal cells?
**Make the plant hard and stiff; die after they mature**
- Also act as supporting cells, but are much more rigid than collenchyma cells
- Often occur in regions of the plant that have stopped growing
- Dead at maturity (but rigid walls remaind as a skeleton that supports the plant)
73
What do water-conducting cells in xylem do? Are they alive or dead? What are the two types?
**- Conduct water and minerals
- Dead elongated cells**
- Two types: tracheids and vessel elements; both tubular, elongated cells
- Cellular contents of these cells pass through structures leaving thick cell walls that allow water to flow (dead at maturity)
74
What do sugar-conducting cells in phloem do? Are they alive or dead?
**- Conduct sugar
- Alive but lack many organelles**
- Sieve cells or also called sieve tube elements
- Alive at maturity, but lack nucleus, ribosomes, vacuole, cytoskeletal elements to allow for more room for nutrients to pass through
- Connected by sieve plates
75
What is photosynthesis? Where does it take place? What is the formula?
- Chloroplasts capture light energy and convert it into chemical energy that is stored in sugar
- Within parenchyma cells
6 CO2 + 12 H2O + Light energy -> C6H12O6 + 6 H2O
76
How many chloroplasts do parenchyma cells in the palisade mesophyll contain?
30-40
77
How many membranes surround the stroma in chloroplasts?
What are the sacs called that contain the chlorophyll in the stroma?
- 2
- Thylakoids
78
Where and how do water and minerals enter the plant?
- Through the roots
- Through osmosis (primarily)
Water moves from an area of high concentration (soil) to an area of low concentration (root cells) across a semi-permeable membrane
79
What do root hairs do?
Increase root surface area
80
What are the three routes water/minerals are transported from cell to cell in the roots?
**Apoplastic route:** within the cell wall or extracellular space (or through dead cells)
**Symplastic route:** through cells via plasmodesmata
**Transmembrane route:** through cells with repeated crossing of cell membranes
81
How is bulk flow of sap upwards possible?
Transpiration: loss of water vapour from leaves
82
What is the cohesion-tension hypothesis?
- Transpiration provides the pull for the ascent of water
- Cohesion of water molecules transmits this pull along the entire length of the xylem
- Adhesion of water molecules to cell walls prevents water from moving back to roots and provides the force to pull water up the sides of the xylem
83
What are stoma? What do they do?
- Openings that allow for gas exchange
- 95% of the water lost in a plant is through the stomata (transpiration)
84
What are vascular bundles?
Which is adaxial and which is abaxial
- Formed by the xylem and phloem, and supporting and protective tissues
- Xylem is adaxial, meaning it is closer to the centre of the stem or root
- Phloem is abaxial, meaning it is closer to the exterior
85
What is different in eudicot stems vs monocot stems?
In eudicot stems, vascular bundles are arranged in a ring, whereas in monocot stems, they are scattered throughout the ground tissue
86
What is the simplified version of the photosynthesis equations?
6 CO2 + 6 H2O + Light energy -> C6H12O6 + 6 O2
87
How is light energy converted into ATP and NADPH while producing O2 as a byproduct in the thylakoids? (Light-Dependent Reaction)
1. Light is absorbed by chlorophyll in Photosystem II (PSII)
2. H2O is split into O2, protons (H+), and electrons (e-)
3. Electron transport chain moves electrons from PSII to Photosystem I (PSI), releasing energy used to pump H+ into the thylakoid lumen, creating a proton gradient
4. H+ flows back into the stroma via ATP synthase, generating ATP
5. Electrons reaching PSI are re-energozed by light and transferred to NADP+, forming NADPH
88
What does the Calvin Cycle do? (Light-Independent Reaction)
Use ATP and NADPH to fix CO2 and synthesize glucose precursors, in the stroma
1. **Carbon Fixation:** RuBisCO enzyme catalyzes the reaction between CO2 and ribulose-1,5-biphosphate (RuBP) to form 3-phosphoglycerate (3-PGA)
2. **Reduction:** 3-PGA is phosphorylated by ATP and reduced by NADPH to form glyceraldehyde-3-phosphate (G3P)
3. **Regeneration:** Some G3P exits the cycle (eventually forming glucose); the rest regenerates RuBP, using ATP
89
What is translocation?
- Transport of the products of photosynthesis (principally sugars)
90
What does pressure flow cause?
Sugar to flow through sieve tubes from sites of sugar production to sites of sugar use or storage
91
What are essential elements? What are they absorbed by?
- Minerals that are required for plants to complete their life cycle
- The roots
These are the building blocks to make cells, proteins, and enzymes
92
What are some elements that plants require?
- Nitrogen
- Phosphorus
- Potassium
- Sulfur
- Magnesium
- Chlorine
- Nickel
93
What are minerals? How much of a plant's dry mass do they account for? What makes up the other part?
- Simple inorganic nutrients that cannot be synthesized by an organism
- Minerals account for ~4%
- Carbohydrates ~96%
94
How do scientists determine essential minerals? How does this process work?
Hydroponic culture!
- Plants are grown in a solution of minerals instead of in soil
- This isolates the variable we want to see, since soil can have a lot of elements
95
What are macronutrients? What are micronutrients?
- Major essential elements plants need in relatively large quantities
- Essential elements needed in smalled quantities
96
What are the 3 numbers on a bag of fertilizer?
Ratios of:
- Nitrogen
- Phosphorus
- Potassium
97
How do plants get nitrogen?
Through the nitrification process:
1. Bacteria convert N2 to ammonia (or from decomposition or animal waste)
2. Bacteria convert ammonia to nitrites
3. Bacteria convert nitrites to nitrates, which are useful to plants!
98
How do plants get phosphorus?
- Phosphorus present in soil from weathering of rocks
- Soil microbes and root exudates help solubilize bound phosphorus, making it more available for uptake
- Most plants for symbiotic relationships with mycorrhizal fungi, which extend hyphae into the soil and enhance phosphate uptake, especially in low phosphorus conditions
99
What kind of transport system is used to move phosphates into plants? Why?
- Energy-driven transport systems
- Phosphate concentration in the soil is much lower than in plants
100
What do fungi get from plants in a mutualistic relationship?
Carbon
101
Where does potassium originate from? How do plants get potassium?
- Originates from weathering of potassium-bearing minerals and decomposition of plant and animal residues
- Potassium is taken up by specific K+ transporter proteins in the root epidermal cells, mainly via active transport
102
How do root hairs take up potassium?
Roots hairs take up water and dissolved minerals from pores between soil particles
103
What is mixotrophy?
Where organisms combine autotrophy and heterotrophy
104
What's an example of an organism that is mixotrophic? How do they digest the animals?
- "Carnivourous" plants that often live in nutrient poor soils
- Prey is captures
- Enzymes are secreted for external digestion
- Elements are transported by endocytosis (or active transport mechanisms) in the glandular cells
105
What colour is a healthy leaf? A phosphate deficient leaf? Potassium deficient? Nitrogen deficient?
Healthy: green
Phosphate: pink/purple edges
Potassium: orange then yellow edges
Nitrogen: yellow and orange down the middle
106
What were the first plants? Where did they live?
- Types of green algae
- They were aquatic
107
What happened about 480 mya, when unicellular charophytes evolved?
- They were able to survive on land!
- Had more access to sunlight and carbon dioxide
- Could photsynthesize more efficiently
- Produced more oxygen!
108
How and where did some ancient charophytes grow?
In wide flat mats in shallow water or on mud flats
109
What were the first land plants like?
- Nonvascular
- Needed to grow directly on or near water
- No roots - not much organic soil - also no vascular tissues in their shoots
110
What are the benefits of moving from water to land? What are the challenges?
Benefits:
- Unfiltered sunlight
- More carbon dioxide
- Few/no herbivores and pathogen
- Mineral substrates
Challenges:
- Scarcity of water
- Solar radiation
- Lack of structural support against gravity
111
What is a cuticle? What does it do?
- A waxy coating that is present on most exposed surfaces
- Avoids desiccation
- A form of waterproofing that also mediates solar radiation
112
A cuticile limits the ability of the plant to absorb water; what did they evolve to get around this?
- Plants evolve roots that are protected from the sun and draw moisture from the soil
113
What is sporopollenin? Why is it needed?
- A durable polymer that covers exposed zygotes of charophytes and the walls of plant spores
- When charophytes evolved out of water, reproduction became a barrier because the gametes were too vulnerable, therefore needed protection
114
What are some structures that safeguard offspring of plants?
- Pollen grains
- Seeds
- Cones
- Fruits
115
What are two ways plants solved gravity challenges on land?
- Turgor pressure
- More robust structure
116
What is turgor pressure/hydrostatic pressure?
- The ability to regulate the pressure of fluid within cells
- Changes in osmolarity allow the flow of **water into cells filling the vacuole**
- Due to their tough cell wall (plants) **the cell can become swollen and rigid**
- This allows plants to either hold position or move body parts
117
What are some tissues that increase structural support in plants?
- Collenchyma (thick cellulose cell walls)
- Schlerenchyma (thick cell wall of cellulose and a lignified secondary cell wall)
- **Really tough parts of plants like coarse fibers and wood**
118
What are auxins?
A group of plant hormones that control the growth of plants by modulating cell division
119
How do stems respond to high concentrations of auxins vs roots?
Stems grow more
Roots grow less
120
What does phototropism do?
Causes an unequal concentration of auxins to cluster in the stem away from the light, causing that side to grow faster and bend toward the light
121
What does geotropism do?
- Causes an unequal concentration of auxins to cluster on the underside of organs
- In roots it slows growth (causing them to grow down)
- In shoots they grow more (causing them to grow up)
122
In summary, what are non-vascular land plants?
- Early colonizers of land
- Modern examples are mosses, liverworts, and hornworts
- Evolved the: cuticle, stoma, rhizoids, and sporopollenin
- Were the dominant (and only) land plant for 40 million years during the Ordovician period
123
In summary, what are vascular seedless land plants?
- The beginning of being able to exploit the soil and enter drier habitats
- Modern examples are ferns and club mosses
- Evolved the : roots and shoots, proper leaves, vascular system
- Changed the game!
- Became the dominant land plant for the next 150-200 million years with humble beginnings, but becoming a major dense forest forming plant with various species of tree fern covering the landscape
- There are still living tree ferns today!
124
In summary, what are vascular seeded land plants?
- Evolved to live across a range of habitats and niches
- Divided into gymnosperms and angiosperms
- Evolved the: seeds and means of seed dispersal, collenchyma and schlerenchyma tissue
125
What are gymnosperms? When were they evolved?
- Evolved in the Triassic and dominated for 150 million years
- All are **perennial woody plants**, include conifers, cycacds, and ginkgo
- Name means "nake seeds", based on the unenclosed condition of their seeds
- Seeds develop either on the surface of scales or leaves, which are often modified to form cones
126
What are angiosperms? When did they evolve?
- Evolved in the Cretaceous and have dominated since
- Range from annual to perennial, and herbaceous to woody
- They include all forbs, grasses and grass-like plants, majority of broad-leaved trees, shrubs, vines, cacti, succulents, and most non algae aquatic plants
127
What are angiosperms distinguished by?
- Flowers, the reproductive organs or flowering plants
- Endosperm within their seeds that forms after fertilization, but before the zygote divides, which provides food for the developing embryo (the cotyledon)
- Fruits, a closed carpel that completely envelop the ovules (the seed)
128
How did plants pave the way for us?
- Modulate global CO2 and O2 levels
- Vascular plants were able to colonise land away from water
- Significantly increased the bio-available chemical energy (the world runs on sugar)
- Produced organically enriched soils that allowed for more plants, and the formation of todays ecosystems
129
What is animal form and function?
| like what does each mean and what does the study of them show?
Form: structure, anatomy
Function: physiology
The comparative study of animals reveal form and function are closely correlated
130
What are the basic principle of animal form and function?
- Form and function in animals are correlated
- Animals' body plants exhibit hierarchical organization
- The activity of animals' tissues, orans and organ systems and coordinated
- Animals exchange material with the environment
-Animals maintain homeostasis: osmoregulation, thermoregulation/energy requirements
131
What are some examples of form and function being correlated in animals?
Ears in jackrabbits:
- Form: thin, large
- Function: acute sense of hearing, heat exchange
132
What is convergent evolution?
Evolution of similar features in independent evolutionary lineages
133
What are the different kinds of animal cells?
1. Stem cells: can be anything! aren't specified yet
2. Intestinal cells: absorb nutrition
3. Red blood cells
4. Muscle cells: special cells for contraction
5. Liver cells: detoxify blood, secrete enzymes
6. Nerve cells
134
What are the four kinds of animal tissues? What does each one do?
1. Epithelial: Covers **outside of bod**y, lines organs and cavities
2. Connective: **holds** many types of **tissues and organs together**
3. Muscle: responsible for **movement**, **heart contraction**
4. Nervous: Recevies, processes, and **transmits information**
135
True or false: the activity of animals' tissues, organs, and organ systems are coordinated
True!
136
What is the endocrine system? What is the nervous system?
- Hormones released into the blood; slow, gradual changes, long distance signaling, chemical
- Neurtransmitters released onto other cells; fast, rapid response, often short distance signaling, electrical/chemical
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How do animals exchange material with the environment?
Materials such as nutrients, waste products, and gases must be exchanged across the cell membranes of animal cells
The rate of exchange is proportional to a cell's surface area
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What are regulators?
Maintain a constant internal environment
139
What are conformers?
Allow internal conditions to vary with external ones
Large fluctuationsin the external environment induce equally large responses of the control system to offset the disturbance
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What does homeostasis mean?
Same; standing still; maintaining internal stability
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How is homeostasis often maintained?
Through negative feedback pathways
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What is negative feedback? What is an example?
- The response opposes or removes the signal
- Ex. blood glucose increases (following a meal) -> insulin is released -> blood glucose decreases (as insulin takes glucose out of the blood) -> no more insulin is released
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What are positive feedback pathways? What is an example?
- The response reinforces the signal
- Ex. fetus pushes against cervix -> cervix stretches -> sensory signals sent to brain and oxytocin (hormone) is released -> oxytocin contracts uterus -> fetus moves down and pushes against cervix -> cervix stretches.......
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What is osmoregulation?
The process by which animals control their solute concentration and water volume
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What is osmosis?
- Net movement (diffusion) of **water** across a semi-permeable membrane from a region of low **solute** concentration to a region of high solute concentration
- Water diffuses until the solute concentration is equalized
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What is osmolarity?
Total concentration of all the solutes in a solution
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What is a semipermeable membrane?
Permits the diffusion of water but not solute
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What is isoosmotic? How does water move in these solutions?
- When two solutions have the same osmolarity
- If a membrane separates the solutions, water will move across the membrane in both directions equally = no net movement of water
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When solutions differ in osmolarity what is the more dilute solution called? What about the one with a great concentration?
- Hypoosmotic
- Hyperosmotic
150
Does a hyperosmotic solution have more water or solute?
More solute; less water
Reversed for hypoosmotic
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What happens to animal cells in hypotonic solutions?
- Lysis!
- Cells swell with water and burst
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What happens to animal cells in hypertonic solutions?
- Crenation
- Cells shrink and develop surface protrusions
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What is osmotic pressure?
Pressure required to oppose the movement of water by osmosis
154
Are animals in freshwater hypoosmotic or hyperosmotic to the environment?
Do they gain or lose water?
Do they gain or lose ions?
- Hyperosmotic
- Gain water
- Lose ions
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Are animals in saltwater hypoosmotic or hyperosmotic to the environment?
Do they gain or lose water?
Do they gain or lose ions?
- Hypoosmotic
- Lose water
- Gain ions
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What makes sharks different from other saltwater animals?
- Sharks are not hypoosmotic!
- They contain high concentrations or urea (nitrogenous waste) and trimethylamine oxide (organic molecule that protects proteins from damage by urea)
- **Sharks are hyperosmotic but hypoionic**
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What do the kidneys do in dehydrating environments?
Conserve water
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What are kidneys comprised of? What do these things do?
- Comprised of nephrons
- Blood is filtered into nephrons
- Some water/ions are reabsorbed into the blood
159
In the kidney, where does a lot of reabsorption of water take place?
The loop of Henle
160
What does ADH do?
Helps terrestrial mammals osmoregulate!
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What is bioenergetics?
The overall flow and transfomation of energy in an animal
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What is energy required for in animals?
Growth, repair, activity, and reproduction
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What is metabolic rate?
What is it measured in?
What is it determined by?
- The amount of energy an animal uses during a given time interval
- Measured in joules or kilocalories
- Determined directly by the amount of heat generated by metabolism or indirectly by the amount of oxygen consumed or carbon dioxide producted
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Do larger animals or smaller animals have higher metabolic rates?
- Larger animals have higher metabolic rates than smaller animals
- BUT smaller animals have higher metabolic rates *per gram* than larger animals
- Bigger bodies; more energy needed to keep it alive
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Every species have an optimal temperature range. How is this maintained?
Modifications in physiology or behaviour to maintain temperature within that range
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What are endotherms?
- Rely on heat generated through metabolic processes to regulate body temperature
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What are ectotherms?
- Do not generate heat (or not enough to elevate body temperature) - rely on heat from external sources
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What are homeotherms?
Maintain stable body temperature
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What are poikilotherms?
Allow body temperature to fluctuate with environment
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What is radiation?
The emission of electromagnetic waves by all objects warmer than absolute zero
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What is evaporation?
The removal of heat from the surface of a liquid that is losing some of its molecules as gas
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What is convection?
The transfer of heat by the movement of air or liquid past a surface
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What is conduction?
The direct transfer of thermal motion (heat) between molecules in contact with each other
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What is evaporative cooling?
- Sweating
- Panting
- External fluids
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What is urohidrosis in birds?
Birds produce waste on their legs to cool themselves down
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What is vasodilation?
- Required a thin layer for diffusion of heat
- Heat loss from our blood across a surface
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What is gular fluttering in birds?
- A cooling mechanism where the gular sac is rapidly expanded to increase the speed of air moving through the sac and buccal cavity
- As fast air passes, heat moves from the blood vessels close to the surface (convective) and also through the moist membranes (evaporative)
179
What is insulation?
- Maintaining body temperature; prevents heat loss
- Reduces the flow of heat into or out of an organism
- Mammal and birds
- Skin, hair, blubber, fur, feathers
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What is countercurrent blood flow (to raise body temperature)?
1. Arteries carrying warm blood to the animal's extremeties are in close contact with veins conveying cool blood in the opposite direction, back toward the trunk of the body. This arrangement facilitates heat transfer from the arteries to veins along the entire length of the blood vessels
2. Near the end of the leg or flipper, where arterial blood has been cooled to far below the animal's core temperature, the artery can still transfer heat to the even colder blood in an adjacent vein. The blood in the veins continues to absorb heat as it passes warmer and warmer blood travelling the opposite direction in the arteries
3. As the blood in the veins approaches the centre of the body, it is almost as warm as the body core, minimizing the heat loss that results from supplying blood to body parts immersed in cold water.
181
What are some behavioural modifications that are key in regulating body temperature?
Sun exposure:
- Warm up in sun
- Cool down in shade
Water exposure:
- Enter water to cool down
Stable habitat:
- Minimize shifts in ambient temperature
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What is regional endothermy?
- Some ectotherms can regulate body temperature to an extent
- Ex. fast swimmers in cold water such as tuna, sharks, marlins
183
What are range shifts?
- Animals moving poleward
- Entering deeper, colder water
184
What do animals do when they are too hot and they can't move or there is no where to go?
- Hibernation!
- Controlled decrease in body temp to conserve energy
185
What is gas exchange?
- Gases (O2 and CO2) move by diffusion from a region or higher partial pressure toa region of lower partial presure
- Partial pressure being pressure exerted by an individual gas in a mixture
- O2 is delivered from the environment to the cells (to be used in cellular respiration!)
- CO2 is eliminated from cells into the environment
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What is the pathway for oxygen?
- Breathing
- Pulmonary O2 diffusion
- Circulatory O2 delivery
- Tissue O2 diffusion
- Tissue O2 utilization
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What do animals use as a repiratory medium?
- Air or water
- Less O2 in water than in air
- Obtaining O2 from water requires greater efficiency than air breathing
188
What do animals require between their cells and respiratory medium?
How does gas exchange occur across respiratory surfaces?
What are some examples of respiratory surfaces?
- Large, moist respiratory surfaces
- Diffusion
- Outer surface, skin, gills, tracheae, and lungs
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What are trachael systems? How do they work?
- Found in terrestrial insects
- Oxygen enters through **spiracles** and moves through the body via the **tracheal tubes** and branching **tracheoles**
- No connection between the respiratory and circulatory systems
190
What are gills?
Outfoldings of the body that create a large surface area for gas exchange
191
How do fish gills function?
A fish continuously pumps water through its mouth and over gill arches, using coordinated movements of the jaws and operculum (gill cover) for this ventillation. Each gill arch has two rows of gill filaments, composed of flattened plates called lamellae. Blood flowing through capillaries within the lamellae picks up O2 from the water. The countercurrent flow of water and blood maintains a partial pressure gradient down which O2 diffuses from the water into the blood over the entire length of a capillary.
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How does countercurrent exchange work in fish?
- Water and blood flow in opposite directions
- Very efficient
193
What's a reason that some animals likely transitioned from water to land?
Low O2 in the water likely led some animals to start breathing air
194
What is bimodal breathing in amphibians? What form do they use as larvae? As adults?
The adult salamander uses its skin and lungs to exchange gases with the environment. Before maturity, it uses external gills while in a watery environment.
- Larvae use gills and skin
- Adults use lungs and skin
195
What are lungs?
Organs of the respiratory system in reptiles, birds, and mammals (and most adult amphibians... even some fish)
- The respiratory system (open or closed) transports gases between lungs and the rest of the body
- The size and complexity of lungs correlate with an animal's metabolic rate
196
What do birds' air sacs allow them to do?
Exchange gas on both inhalation and exhalation
197
How does air move through the lungs of mammals?
Through the pharynx, larynx, trachea, bronchi, and bronchioles to the alveoli, where gas exchange takes place
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What are alveoli? What are the types of cells?
The site of gas exchange
Type 1: thin; allow exchange of gases
Type 2: synthesize and secrete surfactant
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What is tidal exchange?
In mammalian lungs, air enters the system and mixes with some stale air
200
Compare the efficiency of counter current, cross current, and tidal exchange?
Counter Current > Cross Current > Tidal Exchange
201
How does a flat body enhance diffusion?
- Increases surface area and minimizes diffusion distance
- Soime animals use cilia, flagella, gastrovascular cavities, etc. to circulate substances instead of a circular system
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What are circulatory systems comprised of? What is its job?
- A circulatory fluid
- A set of interconnecting vessels
- A muscular pump, the heart
- Exchange gases, absorb nutrients, transport hormones, immune cells, etc. and dispose of wastes
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What is an open circulatory system?
- Blood or hemolymph bathes organs directly in an open circulatory system
- Relies on movement
- Fluids mix
- Found in anthropods, most molluscs, some annelids, and some invertebrates
204
What is a closed circulatory system?
- Blood is transported within closed vessels in a closed circulatory system (circulatory fluid and interstitial are seperate)
- Found in some annelids, cephalopods and vertebrates
205
Do veins bring blood into or away from the heart?
Do arteries bring blood into or away from the hear?
Veins: in
Arteries: out
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Where do oxygen and CO2 diffuse in circulatory system?
In the capillaries
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What are arterioles?
Smaller arteries
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What is the flow of blood in a closed system?
From heart to capillary bed back to heart
209
What are some advantages to a closed circulatory? What are some disadvantages?
Advantages:
- More efficient at transporting circulatory fluids to tissues and cells
- Distribution of blood flow can be regulated
Disadvantages:
- Energetically expensive
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What is the heart? What are atria? What are ventricles?
Heart: two of more muscular chambers
- Atria receive blood
- Ventricle pump blood out of the heart
211
What are the different blood vessels?
Arteries, capillaries, veins
- Arteries: from heart to capillaries
- Veins: from capillaries to heart
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What is a single circuit circulatory system?
Blood passes through the heart once in each complete circuit
213
What is a double circuit circulatory system?
Blood passes through the heart twice
- Blood moving from the heart to the rest of the body (systemic circuit)
- Blood moving from the heart to respiratory organ (pulmonary circuit)
214
What are the four chambers of a fish heart?
- Sinus venosus: pacemaker; weakly contractile
- Atrium: weakly contractile; used to fill ventricle
- Ventricle: main propulsive force
- Bulbous arteriosus: extension of ventricle
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What kind of circulatory system do fish have? What does this entail?
What are the benefits and limitations?
Single circulation
- Blood passes through the heart **once in a circuit**
- Blood passes through two capillary beds before returning to the heart
Benefits:
- Not energetically expensive
Limitations:
- Heart needs to pump with enough force to pump blood through two capillary beds
- Heart receives **oxygen poor** blood
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What kind of circuit do amphibians have?
Incomplete seperation of pulmonary/systemic circuits
217
How does blood flow in amphibian hearts?
What are the benefits to this system? Limitations?
How many chambers is the heart?
Blood passes through the heart twice:
1. Pulmonary circuit (going to the lungs; heart -> respiratory organs -> heart)
2. Systemic circuit (heart -> rest of body -> heart)
- Benefit: Allows for shunting of blood depending on if on water or land
- Limitations: Still some mixing of blood in ventricle
- 3 chambered heart
218
Is the ventricle seperated in amphibians?
No, the ventricle is not completely separated into two in amphibians
Ridges try to separate but blood is going ot mix in ventricle
219
What kind of circuit do reptiles have?
Almost complete separation of pulmonary/systemic circuits
220
How does blood flow in reptiles?
Are the ventricles separated?
What are the benefits?
Limitations?
- Blood passes through the heart twice but there is more division of the ventricle (some reptiles have completely divided ventricles)
- Not completely separated ventricles, blood will mix about 10%
Benefits: More separation of oxygen-rich and oxygen-poor blood. Still opportunities for shunting
Limitations: Still some mixing of blood
221
How does the reptillian heart work?
Left atrium-> cavum arteriosum (in ventricle) -> body
Right atrium -> cavum venosum -> cavum pulmonale (both in ventricle) -> lungs
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What kind of circuits do birds and mammals have?
Complete seperation of pulmonary/systemic circuits!
223
How does the blood flow through the heart in birds/mammals?
Benefits? Limitations?
- Blood passes through the heart twice with complete double circulation
Benefits: allows for more oxygenation of tissue (important in endotherms that use a lot of oxygen to generate heat)
Limitations: energetically expensive
224
Describe literally how blood enters and flows through the heart in mammals and birds
Right atria -> right ventricle -> lungs -> left artia -> left ventricle -> rest of body
225
Why double circulation in mammals and birds?
- Birds and mammals are endotherms and require more O2 than ectotherms
- Increased O2 consumption requires more blood flow to tissues
- More blood flow = higher systemic pressure
- If systemic and pulmonary circuits were not divided, then the pressure would also rise in the pulmonary circuit=pulmoanry edema=fluid in lungs=drowning
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How many chambers is the heart in birds/mammals? Which side in oxygen poor? Which side is oxygen rich?
- Four chambered hearts
- Right side oxygen poor
- Left side oxygen rich
227
What do valves do in the heart?
Prevent backflow of blood
228
How does the cardiac cycle work?
- We change blood pressure at different times in our body
- From the beginning of one heartbeat to the beginning of the next heartbeat
- One contraction (systole - pressure when heart is contracted [top number]) and one relaxation (diastole - pressure when heart is relaxed [bottom number]) of cardiac muscle
- Atria contract first, together - then ventricles
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What is stroke volume?
The volume of blood pumped by the left ventricle in one heartbeat
- Stroke volume (ml/beat) x heart rate (bpm) = cardiac output (ml/min)
BIOL1001
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