Topic 19: introduction to animals Flashcards
what specific traits define an animal?
animals are multicellular, heterotrophic eukaryotes with tissues that originated from embryotic layers
what are the 5 characteristics of animals?
1) cell structure and specialization
2) nutritional mode
3) reproduction
4) development
5) motility
since animals lack cell walls, what do they have instead?
the extracellular matric=x (made with structural proteins and collagen)
what makes tissues unique in animals?
they have a group of cells with specific functions and the same structure
what does somatic mean?
non-reproductive
what happens to somatic cells in an animal
they develop into specialized types
what are two specialized cells in multicellular animals/organisms
neurons (nerve cells) and muckle cells
what is the nutritional mode of animals?
chemoheterotrophs
how do animals get organic molecules in their body when they cannot make organic molecules for themselves?
animals need to consume other organisms to obtain these organic molecules
how do animals digest
digest through phagocytosis
do gamete size in animals vary, if so elaborate
yes, egg cells are large and non-motile while sperm is microscopic and motile
what are the common asexual reproduction methods by invertebrate animals?
fission or fragmentation
what are the least common asexual reproduction methods by invertebrates ?
budding
parthenogenesis
development of an embryo from an unfertilized egg cell
benefits of asexual reproduction
1) rapid population growth
2) backup plan in unfavourable conditions
what is the shape of the zygote that forms in animals
spherical
stages of embryotic development in animals
1) diploid zygote undergoes many round of mitotic cell division called cleavage
2)cleavage becomes an eight-celled emryo
3)continued cell division creates a bastula
4) cell undergoes gastrulation with different layers, forming the endoderm, mesoderm, and ectoderm
bastula
a hollow ball of cells surrounded by a central cavity called the blastocoel
gastrulation
stage in embryotic development when the bastula fold inwards and fills the blastocell, forming a pouch that includes the endoderm and the ectoderm
archeteron
pouch formed by gastrulation
What are hox genes
a critical set of genes that determine the body plan and segment identity, coordinate varoius structures during embryotic development
hox genes are highly conserved, what does this mean?
this means that hox gene arrangement and order is conserved and remains similar across all the aniaml phyla
two primary modes of development
direct and indirect development
what is direct development
the animal after birth is a smaller version of the adult form that is not sexually mature
(example: human babies)
what is inderct development
grwoth occurs in stages with morphological and behavioural differences
(example: caterpillars/larvae undergoing metmorphesis to become a butterfly)
what does sessile mean
immoble
what does radial symmetry suggest
that the animal is immoble/sessile
what does bilateral symmetry suggest
movement, lovomotion , posses a central nervous system
cephalization
development of the head region containing sensory organs
what is bilateral symmetry associated with?
cephalization
what are animals characterizaed by?
body plan, which includes morphological and development traits
tissues
specialized group of cells that have common structures and or functions that are isolated from other tissues
diploblastic
animals with two embryotic cell layers (ectoderm and endoderm)
(in radial symmetrical animals)
tripoblastic
inclusion of a mesoderm that gives rise to organs and muscles (in bilateral anaimals)
what do most tripoblastic animals have
a fluid filled cavity
what is a structure that large animals develop
coloem
what do many tripoblastical animal cells have
hemocel
what are some various functions of the coloem
suspend internal organs, allow internal organs to shift without deforming out of the body (ex heart beating)
cushion organs, a hydrostatic skeleton in soft bodied animals
coloem
the fluid-filled body cavity of an animal that contains the internal organs
where does the hemocel form and what is the name of the liquid contained in it?
the hemocel is formed between the mesoderm and the endoderm. the hemocel contains hemolymph
true or false: coloems and hemocels have the same embryotic origin
false
hemocoel
the primary body cavity of most invertebrates, containing circulatory fluid. has an open circulatory system
function of the hemocoel
circulatory system
what do tripoblastics animals (flat animals specifically) lack? and what does the lack of the structure imply?
they lack a hemocoel which implies that they dont require an internal circulatory system and diffusion across the body surface
two categorizations of embryotic development in bilateral (tripoblastic) animals
protosome and deuterosome development
what is the difference in cleavage for protosome and deuterosome development
protostome: spiral and determinate cleavage
deut: radial and indeterminate
what does it mean for radial veleopmetn in a deterosome
cells form and stack difrectly on top of eachother
what does it mean to be indeterminate
early cells retain the capacity to develop into a complete embryo and creates identical twins
difference in coloem formation in protostome and deutorostome development
pro: splitting og solid masses of the mesoderm
deut: mesoderm folds and makes mini pockets from the walls of the archeteron
difference in bastipore fate in pro and deut
pro: becomes the mouth
deut: becomes the anus
name the three clades of bilateral animals
hemichordates, echinoderms, and chordates (they all have deuterostomia)
