ANIMAL PHYLA, DEVELOPMENT Flashcards
What is the common ancestor to fungi and animals?
Choanoflagellates
What 3 lines of evidence indicate that choanoflagellates are closely related to animals?
- Similarity of choanoflagellate cells and collar cells of sponges
- No such cell in other protists, or in fungi and plants
- DNA sequences common only to animals and choanoflagellates
How do fungi feed?
Fungi are heterotrophs which feed through absorption
How do fungi produce spores?
Asexual life cycles
What are hyphae?
Hyphae form interwoven masses called mycelium, which maximize surface-to-volume ratios, this increasing feeding efficiency
What features are unique to animals?
- Eukatyote
- Multicellular
- Heterotrophic
- Cells without cell walls
- Collagen is the main structure protein
- Hox genes
Why would gene duplication events, such as those seen in the Hox gene complex, set the stage for adaptive radiation?
One copy of the gene can perform the original function while other copies are available to take on new functions
How did the Cambrian Explosion increase animal diversity?
- Evolving predator-prey relationship
- Accumulation of O2 in the atmosphere
- Allowed for aerobic metabolism
- Hox gene complex duplication
- Hox complex - family of genes controlling development form
What are the different types of symmetry?
- Bilateral symmetry
- Radial symmetry
What are the characteristics of bilateral symmetry?
- Divided into symmetrical halves
- 3 germ layers
- Cephalization
- CNS development - sensory equipment concentrated at anterior end
- Move actively
What are the characteristics of radial symmetry?
- Symmetry around central axis
- 2 germ layers
- Sessile or planktonic (free floating)
What are the 3 germ layers?
- Ectoderm - outermost layer which covers surface of embryo
- Mesoderm - middle layer which develops into muscle and other organs
- Endoderm - innermost layer which gives rise to digestive tract lining (liver, lungs)
What are the different types of body cavities?
- Coelomate
- Pseudocoelomate
- Acoelomate
What is a coelomate?
A coelomate is an organism with a “true” coelom derived from the mesoderm
What is a pseudocoelomate?
A pseudocoelomate is an organism with a body cavity derived form the mesoderm and endoderm
What is an acoelomate?
An acoelomate is an organism that lacks a body cavity
What are the 7 main phyla of the animal kingdom?
- Proifera
- Cnidaria
- Platyhelminithes
- Mollusca
- Annelida
- Chordata
What are the advantages to sexual reproduction?
- Greater fitness
- Can survive and reproduce in unpredictable, changing environments
What are the disadvantages to sexual reproduction?
- Must maintain the 2 sexes
- Fewer offspring production
- Only females produce offspring
What are the advantages to asexual reproduction?
- More effective in stable environment
- Offspring are clones of parents
- Large numbers can be produced quickly
What are the disadvantages to asexual reproduction?
- Disadvantageous in unstable environments
- Decrease in diversity
Types of asexual production?
- Fission
- Budding
- Fragmentation
- Parthenogenesis
What is fission?
Fission occurs when an organism splits into 2 parts and, if necessary, regenerates the missing parts of each new organism
What is budding?
Budding occurs when part of the body “buds” or separates from the original organism, producing 2 individuals, 1 smaller than the other
What is fragmentation?
Fragmentation is the breaking of individual parts followed by regeneration
What is parthogenesis?
Parthogenesis occurs when an egg develops without fertilzation
What are the types of sexual reproduction?
- Hermaphroditism
- External fertilization
- Internal fertilization