Test 1 Flashcards
(106 cards)
1
Q
What is the first component of a homeostatic process in multicellular organisms?
A
Cells differentiate to form different tissues.
2
Q
How do tissues combine in animals?
A
Tissues combine in different ways to form organs and organ systems.
3
Q
What does each organ system have?
A
Each organ system has a unique function.
4
Q
What is the definition of homeostasis?
A
The process or ability to establish an internal environment around their cells that can be maintained relatively independent of the external environment.
5
Q
True or False: Homeostasis is a static process.
A
False
6
Q
What are the processes and activities responsible for homeostasis called?
A
Homeostatic mechanisms
7
Q
Fill in the blank: Homeostasis is a _______ process.
A
dynamic
8
Q
What adjustments are made in homeostasis?
A
Internal adjustments
9
Q
Homeostasis compensates for changes in which environments?
A
Internal or external environment
10
Q
What is in charge of detecting a change in variable in the homeostatic process?
A
The receptor (sensors)
(Afferent neurons)
11
Q
Where do the receptors send the information, and what is it associated to?
A
The send the information to the control center, associated with nervous and endocrine system.
12
Q
Where do the efferent neurons send the information from the control center
A
The effector (hormone, muscle)
13
Q
What are the characteristics of plants?
A
1) walls made of cellulose
2) all land plants are multicellular
3) sessile/stationary
4)most plants produce chlorophyll as a photosynthetic pigment used in photosynthesis
5) Plants differ from animals in having an alternation of generations life cycle
6) the embryo is retained inside gametophyte tissue
14
Q
What are the two multicellular stages in the life cycle of land plants?
A
Diploid and haploid
15
Q
What is the diploid generation in land plants called?
A
Sporophyte
16
Q
What does the sporophyte generation produce?
A
Spores
17
Q
What is the haploid generation in land plants called?
A
Gametophyte
18
Q
How does the gametophyte generation produce gametes?
A
By mitosis
19
Q
What begins the haploid phase of the plant life cycle?
A
Specialized cells of the sporophyte produce haploid spores by meiosis
20
Q
In plants, what does meiosis produce?
A
Spores, not gametes
21
Q
What are spores?
A
Single haploid cells with fairly thick cell walls
22
Q
What happens when a spore germinates?
A
It divides by mitosis to produce a multicellular haploid gametophyte
23
Q
What is the function of a gametophyte?
A
To nourish and protect the forthcoming sporophyte generation
24
Q
What existed on land 541 million years ago?
A
No birds or other animals, no plants with leaves rustling in the breeze.
This indicates a barren landscape before significant terrestrial life forms evolved.
25
What type of cells had evolved in the preceding eons?
Cells that produce oxygen as a by-product of photosynthesis.
## Footnote
These cells contributed to the radical change in Earth's atmosphere.
26
What effect did solar radiation have on oxygen in the atmosphere?
It converted much of the oxygen into a dense ozone layer.
## Footnote
The ozone layer acts as a shield against ultraviolet radiation.
27
What was the significance of the ozone layer for early organisms?
It allowed early organisms to populate the land.
## Footnote
Before the ozone layer, organisms were primarily confined to underwater environments.
28
Fill in the blank: Cells that produce oxygen evolved as a by-product of _______.
[photosynthesis]
29
True or False: The ozone layer developed before complex life forms appeared on land.
True
## Footnote
The formation of the ozone layer was crucial for protecting early life from harmful UV radiation.
30
What happened 2.4-2.1 billion years ago?
Great Oxidation event
31
Effects of an increase in oxygen in the atmosphere
- displace CH4 (methane), which cools down the earth
- with the uv rays, O2 splits and becomes O3 (ozone)
32
What does the term 'radiation' refer to in the context of plant species?
Rapid evolution and divergence of varied plant species
33
How many living species are encompassed in the kingdom Plantae?
More than 300 thousand
34
Into how many phyla is the kingdom Plantae organized?
10 phyla
35
Name three types of modern plants.
* Mosses
* Horsetails
* Ferns
36
What are two examples of more advanced plant types?
* Conifers
* Flowering plants
37
What are the challenges to overcome when trying to colonize land
- Avoiding dessication
- physically supporting the plant body in air
- obtaining nutrients from soil
- reproducing sexually in environments where water would not be available for dispersal of sperm or eggs.
38
What are the 4 major steps within plant evolution
1- Move to land (Reliant of H2O)
2- Vascular tissue (roots and shoots)
3- Seeds
4- Flowers
39
What is most likely the ancestor of modern plants
A group of green algae called charophytes
40
what is the representative of thew charophyte lineage commonly known as
stonewort, due to the calcium carbonate that accumulates on its surface
41
are green algae plants?
No
42
synapomorphies between charophytes and land plants that indicate the green algae could be their ancestor
- cellulose in their cell walls
- store energy captured during photosynthesis as starch
- light-absorbing pigments include both chlorophyll a and chlorophyll b
43
What are the three phyla within bryophytes
- Hepatophyta (liverworts)
- Bryophyta (mosses)
- Anthocerophyta (hornworts)
44
Similarities between bryophytes and algal ancestors
- nutrients diffuse across membranes
- require H2O for sexual reproduction (flagellated sperm)
- dominant life form : gametophyte
-lack vascular tissue
- poikilohydric (can't prevent desiccation but they can rehydrate)
45
How did the bryophytes colonize bare land
small bodies trap particles of organic and inorganic matter, helping to build soil on bare rock and and stabilizing soil surfaces
46
Where do the bryophytes constitute as much as half the biomass
in boreal forests, and arctic tundra
47
What makes bryophytes clearly adapted for land
- sporophytes of some species have water conserving cuticle and stomata
- they have rhizoids, which anchor them down but don't provide them with nutrients as roots would
48
Particularities of liverworts
- simple body, thallus in the gametophyte generation
- rhizoids
- no stomata but some have pores
49
What is protonema in mosses
a filamentous web of tissues that branches out after the spore germinates
- extremely prolific, asexually produces bud after bud
50
what do the male and female gametophytes have
male: antheridia (flagellated sperm develop)
female: archegonia (eggs develop)
51
How do hornworts differ from nonvascular plants
their sporophytes can become independent of the gametophyte
52
what is a stomata
opening that allows the plant to get its nutrients
53
what challenges do stomata and cuticles help overcoming
- avoiding desiccation
- getting nutrients
54
Did the first fossil of a true vascular plant, rhynia, have leaves and roots
no
55
Function of Xylem vs Phloem
Xylem (center): transports water and minerals upwards
Phloem( outer): conducts sugars from leaves to roots and water from roots to leaves
56
which vascular tissue uses capillary action and evaporation to transport water
xylem
57
which vascular tissue is most efficient at conducting water
xylem (one way flow, adhesive and no walls between cells)
58
What is lignin
- a polymer of phenylpropanoids (monomer = coniferyl alcohol)
- evolved due to high oxygen levels in the atmosphere
- hard to break down
59
function of lignin
- provides support and rigidity to the cell walls in which it is deposited, allowing the plants to grow upright
- resistance to pests/pathogens
60
where does water go in trees
- 4% photosynthesis
- 5% growth
- 95 % evapotransportation
61
how high do most vascular plants grow
under a meter
62
what is the cambium in plants
the growth zone between de phloem and xylem. grows inwards and outwards
63
What phyla are part of the seedless vascular plants
- lycophyta (club mosses)
- pterophyta (ferns, whisk ferns and horsetails)
64
which life form is dominant in seedless vascular plants
sporophyte (2n)
- diploid dominance perhaps advantageous bc backup copy of DNA
65
Lycophyta characteristics
- grow in swampy places (carboniferous forests)
- true roots and leaves (primitive with only one vein)
66
pterophyta characteristics
- second in size to flowering plants
- 13 thousand species
- moist climate (require external water for reproduction
- some are poikilohydric
- plant body is during sporophyte phase
67
Hermaphrodite definition
Both male and female
68
Phyla in vascular seed plants (gymnosperms)
- conifers
- cycads
- gingko
- gnetophyta
69
Characteristics of conifers (coniferophyta)
- 80% of all living gymnosperms
- sporophytes of nearly all are large trees
- woody cones
- needle - like leaves adapted to dry environments
-
70
Characteristics of cycads
- flourished along with dinosaurs in mesozoic era
- some have massive cones that bear EITHER pollen or ovules (dioecious = separate male and female)
- tropics and subtropics
71
Characteristics of gingko
- one specie
- fused needles
- dioecious
- oldest fossil is 270 mya
72
What is an angiosperm
a flowering plant
73
What makes angiosperm the most successful today
- co-evolution of flowering plant and pollinator
- additional more specialized type of cell that is larger and open ended, moving water more rapidly (xylem)
- phloem more effective at transporting sugar
-enhanced nutrition
- dispersal of offspring
74
Provide an example fro the homeostatic loop and its 4 components
Level of glucose in the blood (variable)
-setpoint: 7mmol
-receptors: chemoreceptors in blood vessels
- control center : brain (NS)
- effector: insulin
75
Major challenges land plants had to over come and adaptations that helped them overcome it.
- avoid desiccation : stomata, cuticle
- physically supporting themselves: lignin in vascular tissue
- obtaining nutrients from soil: vascular tissue (phloem, xylem)
- reproducing sexually (not in water): seeds and pollen
76
male reproductive parts of angiosperm (whorl 5)
stamens
- filament (hold-up...
- anthers (contain pollen sac
77
female reproductive parts of angiosperm (whorl 4)
carpel
- style long stem part
- stigma little opening at the top
- ovary at the base which contains one or more ovules
78
other parts of the angiosperm (whorls 1 and 2)
sepals and petals
79
pros of sexual reproduction in plants
genetic diversity (better adapted to changing environments for at least some offspring)
80
cons of sexual reproduction in plants
- costs resources, energy and time
81
pros of asexual reproduction in plants
save energy, resources and time
82
cons of asexual reproduction in plants
no genetic diversity
83
what is the meaning of totipotent plant cells
cells that have the genetic potential to develop into a whole fully functioning plant
84
what can a totipotent cell do under the right conditions
dedifferentiate
it returns to an unspecialized embryonic state and the genetic program that guides the development of a new individual is turned on
85
4 modes of asexual reproduction in plants
1- fragmentation (natural): cells in parent plant dedifferentiate to generate missing plant parts (leaf falls on the ground and grows new plant)
2- Apomixis : diploid embryon develops from an unfertilized egg. resulting seed contains somatic embryo identical to parent
3- Cuttings (human) : pieces of stems or leaves that grow into new plants
4- miscellaneous modified stems
86
fundamental characteristics of animals
- eukaryotic
- multicellular
- cell membranes in direct contact with each other (no cell walls)
- chemoheterotrophs (depend on other life forms for food)
- use oxygen to metabolize there food and store excess energy as glycogen, oil or fat
- motile at some time in their lives
- reproduce either sexually or asexually
87
major challenges animals had to overcome when making their way onto land
- must withstand the effects of gravity (bones/ exoskeleton)
- must be able to breathe air (gils -> lungs)
- must minimize water loss (avoid desiccation)
- must adjust senses so they are suited for air instead of water
88
3 adaptations to life on land by animals
- eggs
- lungs
- internal fertilization
89
compare the adaptation of plants and animals to avoiding desiccation
plants: cuticle, stomata, xylem and phloem transporting water and nutrients
animals: skin/scales, kidneys/organs capable of water retention, adapted behaviours like going in the shade
90
compare the adaptation of plants and animals to withstand the effects of gravity
plants: lignin for structure, roots to get nutrients
animals: skeletal systems and appendages
91
compare the adaptation of plants and animals for gas exchange
plants: stomata, leaves
animals: lungs, trachea (insects)
92
compare the adaptation of plants and animals for reproduction
plants: seeds, pores, pollen
animals: internal fertilization, amniotic egg,
93
what is the first animal
choanoflagellate
94
three major developmental stages common to the early development of most animals
1. cleavage
2. gastrulation
3. organogenesis
95
describe cleavage
multiple cleavage divisions that forms different structures which become the morula (a solid ball/layer of cells).
cleavage continues until ball hollows out to form blastula.
in the blastula, cells are called blastomeres and encapsulate a fluid-filled cavity (blastocoel)
96
describe gastrulation
cells of the blastula migrate and divide (invagination) to form gastrula.
produces three cell layers: ectoderm, endoderm and mesoderm (each tissue and organ of adult animal originates from one of those three)
gut cavity is called the archenteron
97
describe organogenesis
embryonic cells begin to differentiate
- ectoderm: skin, hair, feathers, nervous system (brain, spinal cord and peripheral nerves)
- mesoderm: muscles, skeletal systems, circulatory system, heart, blood vessels
- endoderm: lining of digestive tract, respiratory tract
98
advantages of bilateral symmetry over radial symmetry
bilateral symmetrical animals are triploblastic. they have three germ layers (mesoderm), so skeletal systems, etc.
-natural selection favoured cephalization in bilaterally symmetrical animals, where there is the development of an anterior head where sensory organs and nerve tissue are concentrated.
-allows for the development of specialized body regions
-less passives, able to hunt prey, etc.
-more efficient movement
99
differences in development of deutorosomes vs protostosomes
D: radial cleavage, mesoderm forms from out pocketing of archenteron, first opening is the anus
P: spiral cleavage, mesoderm differentiates near blastopore, first opening is the mouth
100
Why is classifying animals according to their type of coelom is a homoplasy rather than a homology
Because they all have some type of mesoderm, it is just very simplified in the case of acoelomate and peudoceolomates, which could be considered as a "devolution" (it's not because it's also evolution. they are simply, due to natural selection, better adapted to their environments.
101
how many animals can reproduce sexually from the union of sperm and eggs
all
102
what are the disadvantages of sexual reproduction in animals
the same as plants
103
What animals participate in asexual reproduction and what are the three basic mechanisms
many aquatic invertebrates and some terrestrial annelids and insects
fission, budding and fragmentation
104
explain the three basic mechanisms for asexual reproduction in animals
fission(binary) : purposeful division (parent splits into two or more offspring)
budding: a new individual grows and develops while attached to the parent.
fragmentation: pieces separate from the parent's body and develop into new individuals
105
what is the fourth form of asexual reproduction in animals
parthogenesis: virgin birth (not cloning) growth and development of an unfertilized egg. offspring may be haploid or diploid.
in some species the offspring are all female, in others there are male (depends on sex chromosomes)
106
