exam 2 Flashcards
what are the characteristics of animals?
eukaryotic
multicellular
heterotrophic (ingest)
motile at some stage
lack structural cell walls
embryo passes through blastula stage
animal diversity
- animals are multicellular heterotrophs with no cell walls; diverse in form
- inhabit every conceivable habitat
- locomotion is a distinctive characteristic (some are sessile)
- up to approximately 40 phyla
what are cells held together by
collagen (a protein of connective tissue)
cells are often _________
flexible, they have intercellular junctions
how many animals are invertebrates
99%
where can animals live
marine, freshwater, terrestrial, or aerial. they can also live in hosts
all animals…
- are gametes formed by meiosis
- fuse almost immediately to form diploid zygote
- gametes do not go through mitosis
- do not alternate generations
what forms of locomotion can animals have
swimming, walking, flying, gliding, slithering, rolling
what three features define an animal’s body plan?
- the number of tissue types in embryos
- they type of body symmetry (radial vs. bilateral)
- the way in which the earliest events of embryo development proceed
how can animals be categorized by the amount of tissues they have?
- no specialized tissues
- diploblasts (endoderm & ectoderm)
- triploblasts (ectoderm, endoderm, and mesoderm)
what cells in sponges allow them to recreate their sponge shape no matter what happens to it?
totipotent cells
ectoderm
the “covering” of the animal
- skin
- nervous tissue
endoderm
inner most layer of skin; eg. digestive tract
mesoderm
tissues in the organism
- muscle
- bone
- circulatory system
why do these tissue differences matter?
- increased cellular complexity
- increased tissue diversity
- allowed for coelomic evolution
what are the three types of symmetry?
- asymmetric
- radial symmetry
- bilateral symmetry
radial symmetry
multiple planes of symmetry
bilateral symmetry
one single plane of symmetry and they face their environment in one way
protostomes
two holes in early development, mouth forms first
deuterostomes
two holes form in early development, anus forms first
who are deuterostomes
phyla chordata and echinodermata
ecdysozoa
animals that molt
lophotrochozoa
most either have lophophore (a fan of ciliated tentacles around the mouth) or trochophore (two bands of cilia around their middle) larvae
animal phyla
porifera (sponges)
cnidaria (jellyfish)
platyhelmenthes (flat worms)
molluska (clams)
annelida (segmented worms)
nematoda (round worms molt)
arthropoda (bugs)
chordata (vertebrates)
echinodermata (sea urchins)
what phyla are fungi in?
opisthokonta
how do fungi eat
they digest their food (by secreting enzymes into their food) and then they ingest it
what are fungi cell walls made of
chitin
what is the only spore dispersing organ
the mushroom. the majority of of the fungal body is unseen
which of the following is a trait shared by animals and fungi?
A. both make cell walls from cellulose
B. Both have a swimming appendages that do breaststroke
C. Both taste like chicken
D. Both are heterotrophs
E. Both are multicellular
D
what are the fungi phyla
Chytridiomycota (swimming spores)
Zygomycota (zygospores)
Glomeromycota (friends of plants)
Basidiomycota (basidiospores)
Ascomycota (ascospores)
zygomycetes can make spores through…….
mitosis.
chytridiomycota
overall “harmless” decomposers, swimming spores, and caused a huge strain of deaths in amphibians in their skin.
what are the common places of zygomycetes
on food and often cause food spoilage
zygomycota
have zygospores (a tough and resilient that can survive the dry environment of land)
glomeromycota
form endomycorrhizial mutualisms with roots of land plants. without their help, many land plants would not survive on land.
basidiomycota
mushrooms with the gills underneath the cap. makes basidiospores that are made from a spore producing structure called the basidium
ascomycota
have mushrooms with a wrinkly cap, more surface area. have a spore producing sac called the ascus which contains them as well.
what forms can fungi switch between?
yeast and filamentous forms
how can fungi help protect/help humans?
they can make antibiotics like penicillin
many basidiomycota and ascomycota are also what?
parasites or pathogens on plants and animals (ringworm, athletes foot, etc)
how do basidiomycota and ascomycota interact positively with plants?
lichens are associations between a fungal “mycobiont” and “phycobiont”
mycobiont
ascomycete
phycobiont
cyanobacteria
what do basidiomycetes and ascomycetes also participate in?
ectomycorrhizal associations with the roots of plants
binary fission
splitting a cell in half
what are some advantages to asexual reproduction?
- it is fast; simple nuclear division followed by cytokinesis
- all cells/individuals can reproduce; no mate finding
- favorable gene combinations are maintained.
what are some disadvantages to asexual reproduction?
- in a changing environment, adaptation is severely restricted by asexual reproduction.
- risk of extinction by biotic interactions
- no way to mask harmful genes
what are some advantages to sexual reproduction?
- genetic diversity and variance
- better at dealing with and responding to antagonistic biotic interactions (predation, competition, etc.)
- reduces the expression of potentially harmful genes.
what are some disadvantages to sexual reproduction?
- its slow: it is costly to the rate of reproduction
- male and female gametes must be brought into contact
- recombination breaks up favorable gene combinations
asexual reproduction
processes in which new individuals are derived from only one parent and without the fusion of gametes. there are two types: parthenogenesis and fission
parthenogenesis
females produce unfertilized eggs through mitosis that develop through mitosis. (offspring are genetically identical to the adult) (diploid)
fission
reproduction by detachment and subsequent differentiation of groups and mitotically derived cells or tissues (bud off and split)
obligate parthenogenesis
when organisms like rotifers and darwinulid ostracods only experience asexual reproduction
what makes organisms alternate between sexual and asexual reproduction?
environmental cues like water quality, food availability and day length
sexual reproduction
reproductive process in which the recombination of genetic material derived from more than one parent is possible
meiotic parthenogenesis
development of a new individual (male or female) from an unfertilized ‘egg’.
sexual reproduction with fertilization
process of reproduction in which meiotically derived haploid eggs and spermatozoa fuse to create a diploid zygote
gonochorism (dioecy)
sexes are separated and individuals are either exclusively male or female.
hermapphroditism (monoecy)
the same individual can function as both male and as female
simltaneous hermaphrodite
both male and female gametes are produced in the individual at the same time
sequential hermaphrodites
a sexual reversal takes place over time (male and female gametes produced at different times)
protogyny
female to male
indirect development
several larval stages
protandry
male to female
direct development
no larva; juvenile is hatched or born resembling the adult
external fertilization
no mate choice, less effort, less risk
internal fertilizaton
allows mate choice, energetically costly, risky
what is the evolutionary sequence leading to sexual reproduction in animals and land plants?
- asexual reproduction
- acquisition of mechanisms for limited recombination of genetic material
- meiosis
- the evolution of separate mating types
- anisogamy (the adoption of small mobile and larger gametes)
- separation of the male and female functions in different individuals
land plants
a monophyletic group whose common ancestor was an archaeplastid organism that made it on to land
plastid
an organelle that is the result of another endosymbiosis with a cyanobacteria
rhodophyta (red algae)
- multicellular
- sexual reproduction
- chlorophyl d
glaucophyta (walled plastids)
- unicellular
- only asexual reproduction
viridiplantae (plants and pals)
- chlorophyl B
- sexual reproduction
- lack of peptidoglycan
which eukaryotic clades have photosynthetic members?
stramenopila, alveolata, rhizaria, archaeplastida, discoba
how are secondary plastids made
- host cell engulfed a red alga that was capable of photosynthesis.
- the red alga found a home when the food vacuole fused with the hot ER and was safe from digestion.
- symbiotic relationships were established and the red alga becomes the secondary plastid as the host takes over more and more functions.
- they are surrounded by more membranes
how do plants allow for nutrient absorption without drying out?
the waxy, waterproof cuticle prevents evaporation from upper surface, but they still move up through the bottom side.
how do plants deal with solar UV-radiation?
water absorbs and scatters most of the UV light to help prevent damage of DNA and other cellular components.
how to maintain gas exchange with that wax with that wax on the upper surface
specialized epidermal cells called guard cells form an opening (stomata) which lets plants open and close.
what are the adaptations in plants
cuticles, stomata, vascular tissues, complex leaves, seeds, flowers and fruits
what do vascular tissues do?
move water and nutrients up from the soil into the rest of the plant (xylem) and sugars bidirectionally (phloem)
mitosis
diploid to diploid (two identical copies of parent cells)
meiosis
diploid to haploid (four unique daughter cells)
fertlilzation
gametes fusing together with other compatible gametes
how do spores reproduce?
they reproduce directly and do not undergo fertilization
isogamy
gametes that look the same
anisogamy
gametes that look different