Chapter 20 Flashcards
How many lineages are there in multicellular organisms?
three
Describe the cells (function wise) in unicellular organisms and multicellular organisms.
- unicellular = all activities occur in one cell
- multicellular = cells are interdependent and some become specialized for different functions
What are the three lineages of multicellular organisms?
1) red and green algae evolved from archaeplastids
2) brown algae evolved from chromalveolates
3) fungi and animals evolved from unikonts
Where did fungi come from?
nucleariids
Where did animals arise from?
choanocytes (choanoflagellates)
What is an animal?
multicellular eukaryotes
How did animals evolve?
they probably arose from unicellular protists that began living together and eventually became colonial choanocytes which evolved to become animals
are animals heterotrophic or autotrophic?
heterotrophic
How do animals usually acquire nutrients?
through ingestion
Most adult animals are haploid. True or False
False
How do most animals reproduce?
sexually via the diplontic life cycle
are ALL animals only restricted to sexual reproduction?
no, some can reproduce asexually
What organisms classify as multicellular?
fungi, seaweed, animals, and plants
Describe the diplontic life cycle of a starfish?
1) a diploid female starfish goes through meiosis to produce haploid gamete cells (egg)
2) sperm from another starfish fertilizes the egg which forms a diploid zygote
2) the zygote goes through embryogenic stages
3) it becomes a larva or juvenile
4) via metamorphosis, it becomes an adult starfish
How old are the oldest animal fossils?
about 575 - 550 million years ago
Describe the body parts of the oldest animal fossils
soft body partys
when did animals develop hard body parts?
about 535-525 mya
How many animal phyla exist?
35
How many animal phyla are vertebrate?
one
How many animal phyla are invertebrate?
34
what are invertebrates?
organism that lack a vertebral column aka backbone
Animals vary in?
1) symmetry
2) presence of true tissues (number of embryonic tissue layers)
3) type of embryonic development
4) presence/absence of body cavity
What are the different kinds of body symmetry?
Radial and bilateral
What is a radial body symmetry?
- no back or front
- no left or right side
- any divisional plane going through the middle from the top to bottom divides the body into 2 identical halves
what is a bilateral body symmetry?
- it has a ventral surface (below) & a dorsal surface (top)
- it has 2 lateral surfaces
- an anterior end and a posterior end
- there is one division plane that divide the body into 2 halves which are mirror images of one another
What is a tissue
a collection of cells that work together to perform a specific function
where do true tissues arise from?
they arise from embryonic tissue layers
What are the three different embryonic tissue layers?
1) ectoderm
2) mesoderm
3) endoderm
what is an ectoderm?
the outermost tissue layer of the embryo
What is an endoderm?
the innermost layer of an embryo
what is a mesoderm
the tissue layer between the ectoderm and the endoderm
When an animal has all three embryonic tissue layers, what could this mean.
they could possibly have a body cavity
Define body cavity.
the fluid-filled space between the digestive tract and outer body wall
Do animal cells have a CELL wall?
no
In soft bodied animals, the body cavity can function as?
hydrostatic skeleton
What is a hydrostatic skeleton
a structure that provides rigid structure against which muscles contract, making animals move
- formed by the body cavity in soft bodied animals
when animal doesnt have a body cavity, what is it called?
acoelomate
What are the two types of body cavity?
coelom and pseudocoelom
What is a coelom?
a body cavity in which tissues from the mesoderm completely lines it
What is a pseudocoelom?
a body cavity in which tissues from the mesoderm does not completely line it
what do you call an animal with a coelom?
coelomate
what do you call an animal with a pseudocoelom or a false coelom?
pseudocoelomate
Explain the embryonic layer structure in pseudocoelomates.
Ectoderm, mesoderm, pseudocoelom, endoderm
Explain the embryonic tissue layer structure of a coelomate.
ectoderm, mesoderm, coelomate, mesoderm, endoderm
Explain the tissue layer structure of an acoelomate.
ectoderm, mesoderm, endoderm
animals who have true tissues are under the category?
eumetozoans
animals who have true tissues and have bilateral symmetry are under what category?
bilaterians
Animals who have true tissues, have bilateral symmetry and develop a mouth first during gastrulation are under what category
protostomes
Animals who have true tissues (eumetozoans), bilaterans, and develop the anus first followed by the mouth during gastrulation are under what category?
deuterostomes
Which animal phylum doesn’t contain true tissues?
phlyum porifera (sponges)