organismal biology Flashcards
Plants evolved from what color algae?
green
how many known plant species are there?
at least 375,000
what do plants do for the planet?
supply oxygen, food and habitat for all other terrestrial organisms
the closest relatives of land plants
charophytes (green algae)
morphological traits that land plants share with charophytes
cellulose-synthesizing membrane proteins arranged in rings, structure of flagellated sperm, and formation of phragmoplast during cell division
plants move to land provided benefits such as:
unfiltered sunlight, plentiful CO2, nutrient rich soil, and few herbivores
challenges that plants had moving to land
scarcity of water and no structural support
a polymer that prevents zygotes from drying out
sporopollenin
coats charophytes
sporopollenin
found in plant spore walls
sporopollenin
traits that are in land plants but arent in charophytes
multicellular,dependent embryo; walled spores produced in sporangia, and apical meristems
two multicellular stages that plants alternate between
gametophyte and sporophyte
produces haploid gametes by mitosis
gametophyte
produces haploid spores by meiosis
sporophyte
fusion of gametes given rise to the diploid
sporophyte
nutrients are transferred from parent to embryo through what
placental transfer cells
why are land plants called Embryophytes?
the dependency of the embryo on the parent
sporophyte produces spores in multicellular organs called what
sporangia
localized regions of cell division at the tips of the roots and shoots
apical meristems
what makes plants resistant to harsh environments
sporopollenin in spore walls
when do plant spores first appear in the fossil record
470 million years ago
mosses and other nonvascular plants have life cycles dominated by
gametophytes
Bryophytes are represented by what three phyla
phylum Hepatophyta, Bryophyta, and Anthocerophyta
what phylum is liverworts in?
phylum Hepatophyta
what phylum is mosses in?
Phylum Bryophyta
what phylum is hornworts in?
phylum Anthrocerophyta
what group of bryophytes is larger and longer living than sporophytes
gametophytes
are typically present only part of the time and are dependent on the gametophytes
sporophytes
are named for their “liver-shaped” gametophytes
liverworts
long and tapered “horn” shaped structure
sporophytes
grow horizontally and have multiple sporophytes attached
gametophytes
organs that anchor vascular plants into ground and absorb water and nutrients from soil
roots
closely resemble stem tissue of early vascular plants
root tissue
may have evolved from below-ground stems
roots
increase surface area for light capture and conduct most of the photosynthesis in plants
leaves
two types of leaves
microphylls and megaphylls
small, often spine-shaped leaves with a single vein, are found in all other plant groups
microphylls
larger leaves with a highly branched vascular system, are found in all other plant groups
megaphylls
two clades of seedless vascular plants
lycophytes and monilophytes
club mosses, spike mossed, and quillworts
lycophytes
ferns, horsetails, and whisk ferns and their relatives
monilophytes
formed during the Devonian and carboniferous periods
forests of lycophytes,horsetails, and ferns
resulted from the subsequent drop in atmospheric CO2
global cooling and widespread glaciation
decay was slow in what swamp
Carboniferous
undecided organic material slowly turned into what
coal
the first plants to grow tall
ferns and other seedless vascular plants
the dominant vegetation for the first 100 million years of plant evolution
bryophytes and similar plants
began to diversify during the Devonian and Carboniferous periods
vascular plants
what allowed plants to grow tall
vascular tissue
early vascular plants had what
branching sporophytes
live independently of the gametophyte
vascular plant sporophytes
living vascular plants are characterized by
life cycles with dominant sporophytes, transport in vascular tissues called xylem and phloem, well-developed roots and leaves, spore-bearing leaves called sporophylls
two types of vascular tissue in vascular plants
xylem and phoem
conducts most of the water and minerals and has tracheids
xylem
tube-shaped cells
tracheids
what cells are dead at functional maturity and are lignified
xylem cells
Changed the course of plant evolution, enabling their
bearers to become the dominant producers in most terrestrial ecosystems
seeds
originated about 360 million years ago
seed plants
consists of an embryo and nutrients surrounded by a
protective coat
seed
are key adaptations for life on land
seeds and pollen grains
have reduced gametophytes, heterospory, ovules, and pollen
seed plants
help plants cope with drought and exposure
to ultraviolet (UV) radiation
reduced gametophytes,heterospory, ovules, and pollen
is not required for fertilization in seed plants
water
Seed plant life cycles are
sporophyte-dominated
are microscopic and dependent
gametophytes
develop within the walls of spores that are retained within tissues of the parent sporophyte
the gametophytes of seed plants
are seed plants heterosporous or homosporous?
heterosporous
produce megaspores that give rise to female
gametophytes
megasporangia
produce microspores that give rise to male
gametophytes
microsporangia
consists of a megaspore within a megasporangium
ovule
an ovule is surrounded by one or more protective coats called
integuments
typically have one integument
gymnosperms
typically have two integuments
angiosperms
develops into a male gametophyte enclosed
within the pollen wall
microspore
pollen wall
pollen grain
is the transfer of pollen to the part of a seed plant
containing the ovules
pollination
can be transferred long distances by wind or animals,
eliminating the reliance on water for sperm transfer
pollen
are multicellular
seeds
are single cells
spores
can remain dormant for years until conditions are
favorable for germination
seeds
are shorter lived
spores
have stored food to nourish growing seedlings
seeds
do not provide nourishment to gametophytes
spores
can be transported longer distances by wind or animals
seeds
usually drop closer to the parent plant
spores
bear “naked” seeds, typically on cones
gymnosperms
bear seeds exposed on sporophylls that usually
form cones
gymnosperms
Most gymnosperms are cone-bearing plants called
conifers
has 350 living species and large cones and palm like leaves and have flagellated sperm
cycads
thrived during the Mesozoic, but today are the most endangered of all plant groups
cycads
is the only living species in this group
Ginkgo biloba
have flagellated sperms and are mostly in cities because they tolerate air pollution well and Fleshy seeds produced by female trees smell rancid as they decay
Ginkgo biloba
Welwitschia, Gnetum, Ephedra
Phylum Gnetophyta
longleaf pine
pinus palustris
common juniper, douglas fir, wollemi pine, bristlecone pine, sequoia, european larch
phylum coniferophyta
the reproductive adaptations of angiosperms include
flowers and fruits
are seed plants with reproductive structures called
flowers and fruits
angiosperms
are the most diverse and widespread lineage of plants
flowers and fruits
most recently evolved; 130 – 140 mya (Cretaceous)
dominant group of land plants
tremendous morphological and ecological diversity
angiosperms (flowering plants)
The flower is an angiosperm adaptation specialized for
sexual reproduction
transfer pollen from one flower to another
insects or other animals
A flower is a specialized shoot with up to four types of modified leaves called
floral organs
are usually green and enclose the flower bud
sepals
are often brightly colored or scented to attract
pollinators; (wind-pollinated flowers are not)
petals
are microsporophylls, male reproductive organs
stamens
are megasporophylls, female reproductive organs
carpels
protect seeds and aid in their dispersal
fruits
function like parachutes for wind
dispersal
dandelions
are adapted to float in seawater
coconuts
cling to animal fur
Fruits modified as burrs
are eaten by animals and dispersed in their droppings
sweet tasting, vividly colored fruits
Various adaptations of fruits and seeds help to what
disperse seeds
The flower of the sporophyte is composed of
both male and female structures
Male gametophytes are contained within pollen grains produced by
the microsporangia of anthers
develops within an ovule contained within an ovary at the base of the carpel
embryo sac (female gametophyte)
The ovule is entered by a pore called the
micropyle
occurs when the pollen tube releases two sperm nuclei into the female gametophyte within an ovule
double fertilization
appear suddenly and widely in the fossil record from about 100 million years ago
angiosperms
nourishes the developing embryo in the angiosperm life cycle
triploid endosperm tissue
diverged from the lineage leading to angiosperms about 305 million years ago
extant gymnosperms
Hordeum vulgare
barley
paphiopedilum callosum
orchid
phoenix roebelenii
pygmy date palm
magnolia grandiflora
southern magnolia
includes animals, fungi, and related lineages
opisthokonts
the ancestor of fungi was a _____, ________, and _____ organism
aquatic, unicellular, flagellated
animals and fungi diverged when
more than a billion years ago
fungi likely originated where
aquatic habitats
fungi may have colonized land as early as
505 million years ago
fungi are ________ that feed by ______
heterotrophs, absorption
what key trait do all fungi share?
the way in which they derive nutrition
how do fungi absorb nutrients?
from outside of their body
what do fungi use to break down a wide variety of complex molecules into smaller organic compounds
hydrolytic enzymes
the versatility of hydrolytic enzymes contribute to fungis what?
ecological success
what diverse lifestyle and ecosystem roles do fungi exhibit?
decomposers, parasites, mutualists
the most common fungal forms are what
multicellular filaments and single cells (yeasts)
most fungi only exist as
filaments
fungi produce spores through what
sexual and asexual life cycles
fungi propagate themselves by
producing vast numbers of spores
spores are carried long distances by
wind or water
fungal nuclei are _________; with the exception of _____________ formed during the sexual life cycle
normally haploid, transient diploid stages
sexual reproduction requires the fusion of
hyphae from different mating types
signalling molecules fungi use to communicate their mating type
pheromones
the union of cytoplasm from two parent mycelia
plasmogamy
the part of the mycelium that haploid nuclei coexist because they dont fuse right away
heterokaryon
haploid nuclei of each type pair off two to a cell, the mycelium is called
dikaryotic
nuclear fusion producing diploid cells
karyogamy
the diploid phase is short-lives and undergoes ________, producing ______
meiosis, haploid spores
the paired processes of karyogamy and meiosis produce
genetic variation
fungi have radiated into a diverse set of
lineages
have clarified evolutionary relationships among fungal lineages
molecular analyses
have led to the discovery of entirely new groups and previously unknown diversity
metagenomic studies
how many known species of fungi are there
145,000
what is the estimate of the actual number of species of fungi
between 2.2 and 3.8 million
form a sister group and are a basal fungal lineage
cryptomycetes and microsporidians
are unicellular and have flagellated spores
cryptomycetes
where are cryptomycetes found?
globally in soils, and marine and freshwater habitats
is cryptomycetes aerobic or anaerobic?
both
have very small genomes and tiny organelles derived from mitochondria
microsporidians
how do microsporidians produce spores
they produce spores that infect host cells via a harpoon-like organelle
what kind of parasites are microsporidians
unicellular parasites of protists and animals, including humans
include species that function as decomposers, parasites, and mutualists
chytrids
what are chytrids flagellated spores called
zoospores
where are chytrids found?
lakes, soils, and marine habitats including hydrothermal vents
live as parasites or commensal symbionts of animals or as parasites of other fungi
zoopagomycetes
how do zoopagomycetes reproduce
asexually via non flagellated spores
species that reproduce sexually form a durable structure called
zygosporangium
zygosporangium houses and protects what
the zygote
molds in this group include important decomposers
mucormycetes
live as parasites, pathogens, or mutualists with plants
mucormycetes
about 90,000 known species
ascomycetes
live in a variety of marine, freshwater, and terrestrial habitats
ascomycetes
vary widely in size and complexity from unicellular yeasts to elaborate cup fungi and morels
ascomycetes
ascomycetes are often called
sac fungi
named for the saclike asci, in which spores are produced
sac fungi
during the sexual stage, ascomycetes produce fruiting bodies called
ascocarps
more than 25% of all ascomycete species form
lichens
symbiotic associations with green algae or cyanobacteria
lichens
live within plant leaves and produce compounds toxic to insects
ascomycetes
are about 50,000 known species including mushrooms, puffballs, and shelf fungi
basidiomycetes
the cell in which karyogamy and meiosis occur
basidium
the club-like shape of the basidium gives rise to the common name
club fungus
basidiomycetes are destructive plant parasites called
rusts and smuts
multicellular, heterotrophic eukaryotes with tissues that develop from embryonic layers
animals
unlike plants, who produce their own organic molecules, animals
eat living or nonliving organisms
unlike fungi, which digest food externally and then absorb nutrients, animals
ingest food and then digest it internally
are supported by structural proteins such as collagen, rather than cell walls
animal cells
are unique, defining characteristics of animals
nervous tissue and muscle tissues
are groups of cells that have a common structure, function, or both
tissues
in animal reproduction, what is the dominating life cycle
diploid stage
are produced directly by meiotic division in animals
gametes
after fertilization, the zygote undergoes rapid cell division called
cleavage
cleavage leads to formation of a multicellular, hollow
blastula
forming different layers of embryonic tissues
gastrulation
blastula undergoes
gastulation
have at least one larval stage
animals
is sexually immature and morphologically distinct from the adult
larva
larva eventually undergoes
metamorphosis
have Hox genes that regulate the development of body form
most animals and only animals
they can produce a wide diversity of animal morphology
Hox family of genes
spans more than half a billion years
history of animals
includes a great diversity of living species and an even greater number of extinct ones
the animal kingdom
the eukaryotic lineage that is closest to animals
choanoflagellates
the first generally accepted macroscopic animal fossils date from when
about 560 million years ago
the first generally accepted macroscopic animal fossils were found
Ediacara Hills of Australia
marks a period of rapid animal diversification and the appearance of many major groups of living animals
Cambrian explosion
several hypotheses regarding the cause of the Cambrian explosion
new predator-prey dynamics
a rise in atmospheric oxygen
evolution of the Hox gene complex
animal diversity continued to increase throughout the Paleozoic era, but was punctuated by several what
mass extinctions
animals began to make an impact on land by
450 million years ago
made the transition to land around 365 mya
vertebrates
animals can be characterized by
body plans
sets of morphological and developmental traits
body plans
symmetry
are basal animals that lack tissues
sponges
are sessile, filter feeders that lack true
tissues and are among the simplest animal
sponges
what is the name of animals that capture food particles suspended in the water and pass through their body
suspension feeders
are suspension feeders
sponges
Water that is drawn through pores into a cavity in a sponge is called
spongocoel
water goes out of the sponge through an opening called
osculum
even though sponges lacking this they are highly organized
true tissues and organs
different cell types a sponge can have
choanocytes and amoebocytes
flagellated collar cells, generate a water current and ingest food particles by phagocytosis
choanocytes
how many cell layers do sponges consist of
two
the cell layers are separated by a gelatinous region called
mesohyl
are totipotent cells within the mesohyl that digest food,transport nutrients, and make skeletal fibers
amoebocytes
each individual functions as both male
and female
hermaphrodite
are sponges hermaphrodites?
yes
is a basal group of multicellular animals, probably sister to Cnidarians or all other Eumetazoa
Placozoa
They are very flat organisms commonly less than 4 mm in diameter, lacking any organs or internal structures. A total of 4 species have been described, the last 3 only since 2018
Placozoa
are an ancient phylum of eumetazoans
Cnidarians
animals with true tissues
eumetazoans
represent one of the oldest, earliest
branching lineages in this clade
Cnidarians
Cnidaria have diversified into a wide range of both sessile and motile forms including
corals, hydras, and jellies
The basic body plan of a cnidarian is a sac with a central digestive compartment called
gastrovascular cavity
adhere to the substrate by the aboral end of the body (the end opposite the mouth
polyps
is a free-swimming form that has a bell-shaped body with the mouth on the underside
medusa
two variations on the body plan in cnidarians
the sessile polyp and motile medusa
Cnidarians are predators that use what to capture and consume prey
tentacles
unique cells used in defense and prey capture on tentacles
cnidocytes
are specialized organelles within cnidocytes that eject a stinging thread
nematocysts
Extant Cnidaria fall into what two major clades
Medusozoa and Anthozoa
include all cnidarians that produce
a medusa
Medusozoa
Scyphozoans (jellies), Cubozoans (box jellies), and Hydrozoans are part of what clade
Medusozoa
what clade includes sea anemones and corals and can only occur as polyps
Anthozoa
