Introduction to Animal Biodiversity Flashcards
What are the 3 Domains?
(Archaea, Bacteria, Eukarya)
Protists, Plants, Fungi, Animals belong within domain ___?
Eukarya
___% of all animals are invertebrates
95%
Many of the phyla arose ____ years ago
530 Million
How long have animals been around?
more than a billion years
The animal kingdom includes
not only great diversity of
living species, but even
greater diversity of ____
extinct ones
Animal diversification began more than ____ years ago
half a billion
The oldest generally accepted animal fossils that have been found are ___ years old.
575–550
million
Animal diversification appears to have accelerated rapidly from 535 to 525 MYA,
during the Cambrian period, known as the ___
Cambrian Explosion
The most celebrated source of Cambrian fossils is the ___ containing a
cornucopia of perfectly preserved animal fossils.
Burgess Shale
Possible causes of Cambrian Explosion
- increasingly complex predator-prey relationships or
- an increase in atmospheric oxygen.
properties of animals:
- Eukaryotes
- Heterotrophs
- No cell walls
- Eat by ingestion (mostly true)
- Diploid (mostly true)
- Sexual (mostly true)
___ are thought to be the
animal “ancestor”
Choanoflagellate-like organisms
a protistan group that arose between 675 and 875 MYA
choanoflagellates
Sequence data indicates that
choanoflagellates and animals
are ___
sister groups
Choanoflagellate
cells resemble
___ also called,
choanocytes
sponge collar cells
___ are only found
in animals and not in
protists
Collar cells
Evidences that Choanoflagellate-like organisms are thought to be the animal “ancestor” :
- Sequence data indicates that
choanoflagellates and animals
are sister groups
2.Choanoflagellate
cells resemble
sponge collar cells
(choanocytes)
- Collar cells only found
in animals and not in
protists
9 General Animal Characteristics
- Animals are multicellular
- Cells lack cell walls
- Animals are heterotrophic (vs. autotrophic)
- Most reproduce sexually w/ diploid stage usually dominating life cycle
- After a sperm fertilizes an egg the zygote undergoes cleavage, leading to the formation of a blastula, embryonic tissues and gastrula.
- Cell specialization: specialized neural cells (nervous tissue) and muscle cells (muscle tissue) are unique to animals
- During development three germ layers give rise to the tissues and organs of the animal embryo. Animal body plans vary by organization of tissues.
- Tissues are held together by structural proteins such as collagen.
- All animals, and only animals, have the highly conserved Hox family of genes that regulate the development of diverse body form.
After the gastrula stage, many animals develop directly into adults, while some develop into one or more ___ stages before taking the adult form.
larval
A ___ is an immature individual that looks
different from the adult animal.
larva
A larva undergoes a major change in body form,
called ___, and becomes a
reproductively mature adult.
metamorphosis
Animals can be characterized by basic features of
their ___
body plan
Animal body plans vary in:
- presence of true tissues
- symmetry
- number of embryonic layers
- presence of a body cavity
- details of their embryonic development
These characters, as well as DNA sequence, can be
used to determine the ___ of animals.
phylogeny
Animals either have ___ or ___ symmetry
radial or bilateral
have a top and bottom but lack back
and front or R and L sides. An
imaginary slice through the central axis
divides them into mirror images.
Radial symmetry
Animals with this symmetry have
mirror-image right and left sides and a
* distinct head, or anterior end,
* tail, or posterior end,
* back, or dorsal, surface, and
* bottom, or ventral, surface.
bilateral (two-sided) symmetry
The most abundant phylum
Arthropoda
There are ___ species of arthropods
> 1 million
they have:
* an open circulatory system and
* an exoskeleton of chiton, an external skeleton that
protects the animal but must be shed in the process of molting to permit growth.
* body that includes a head, thorax, and abdomen, although these segments may be fused.
arthropods
the exoskeleton is made of a tough fibrous material
called ___
chitin
It gives the skeleton strength and flexibility. It also has several pairs (5 or more) of jointed appendages (movable arms and legs).
the exoskeleton
the body of an arthropod is completely covered by the ___, an exoskeleton made of chitin
cuticle
When an arthropod grows, it molts its exoskeleton in a process called ___
ecdysis
Insect life cycles often include ___, during which
the animal takes on different body forms as it develops from larva to adult.
metamorphosis
types of metamorphosis
- complete
- incomplete
a free-living larva transforms from a pupa into an adult.
complete metamorphosis
the transition from larva to adult is achieved through
multiple molts, but without forming a pupa.
incomplete metamorphosis
this phylum has a pseudocoelom and a complete digestive tract
Nematoda
Nematodes have these characteristics:
- bilateral symmetry,
- three tissue layers = triploblastic
- a nonliving cuticle covering the body that prevents them from drying out,
- a pseudocoelom body cavity that functions to distribute nutrients and as a hydroskeleton
- a complete digestive tract with a mouth and anus.
Humans host at least ___
species of parasitic
nematodes.
50
What phylum is considered the simplest bilateral animals?
Platyhelmenthes (Flatworms)
- Live in marine, freshwater, and damp terrestrial habitats.
- Some are parasitic and others are free-living.
Platyhelmenthes
There are three major groups of flatworms:
- free-living flatworms
- flukes
- tapeworms
parasitic flatworms with complex life cycles and suckers to attach to their hosts.
flukes
parasitic inhabitants of the digestive tracts of vertebrates, have no mouth, and simply absorb nutrients across their body surface.
tapeworms
type of flatworms that have:
* heads with light-sensitive eyespots,
* flaps to detect chemicals,
* dense clusters of nerve cells that form a simple brain and a pair of
nerve cords that runs the length of the body
* a branched gastrovascular cavity with a single opening.
Free-living flatworms (planarians)
Phylum Mollusca have these characteristics:
- a muscular foot that functions in locomotion,
- a visceral mass containing most internal organs,
- a mantle, which may secrete a shell that encloses the
visceral mass, and - a true coelom and a circulatory system that pumps
blood throughout the body. - Many molluscs feed with a rasping radula, used to scrape up food.
- The life cycle of many marine molluscs includes a ciliated trochophore larval stage.
the largest invertebrates
Squids
The largest group of molluscs and include the snails and slugs.
Molluscs: Gastropods
group of molluscs that include clams, oysters, mussels, and scallops and have shells divided into two halves that are hinged together.
Molluscs: Bivalves
Group of Molluscs that are fast, agile predators,
have large brains and sophisticated sense organs, including complex image-focusing eyes
Mollusca: Cephalopods
Phylum ___: The segmented worms
Annelida
Annelids have these characteristics:
- segmentation, the subdivision of the body along
its length into a series of repeated parts, - a true coelom that functions as a hydrostatic skeleton,
- triploblastic tissue organization
- a nervous system that includes a simple brain and ventral nerve cord, and
- a closed circulatory system in which blood remains
enclosed in vessels throughout the body.
Annelids are found in ___
damp soil, the sea, and most freshwater
habitats.
Types of Annelids:
- Oligochaetes (earthworms)
- Polychaetes
This phylum is characterized by radial symmetry
Cnidaria
Cnidarians exhibit two kinds of body forms:
-polyp (sedentary/dili lihokan)
-medusa (mobile)
___ are carnivores that use their tentacles to
capture prey and to push prey into their mouths.
Cnidarians
are unique stinging cells that capture prey
and function in defense.
Cnidocytes
This phylum has
* No symmetry
* No tissues
* Spicules
* Very primitive/basal
Porifera (Sponges)
Phylum ___ have spiny skin, an endoskeleton, and a water vascular system for movement
Echinodermata
a diverse group including sea stars, sea cucumbers sand dollars, and sea urchins
echinoderms
Echinoderms have:
- an endoskeleton of hard calcareous plates under a thin skin,
- a water vascular system based on a network of water-filled canals that branch into extensions called tube feet, and
- the ability to regenerate lost arms.
Phylum ___ contains vertebrates and their invertebrate ancestors.
Chordata
The simplest chordates:
Tunicates and Lancelets
tunicates and lancelets lack a ___
backbone
Most chordate embryos and/or adults possess:
- a dorsal, hollow nerve cord,
- a flexible, supportive notochord
- pharyngeal slits, and
- a muscular post-anal tail.
