Lecture 2 Flashcards
General (wrong) definition of an animal
Non-Human
Biological definition of an animal
Belonging to the kingdom Animalia or Metazoa
Animalis meaning
Having breath/soul
Diversity and number of species
There are a lot of different animals
Diverse species are thanks to
Evolution
Diverse habitats are thanks to
environmental changes
Diverse characteristics are a result of
adaptation
Species habitats and characteristics
Interact and influence each other
Coevolution
Things that evolve together
All taxa evolved from what
A single common ancestor
LUCA
Last universal common ancestor
Taxa
any group that have similar aspects
Phyla
Taxonomic category above class and below kingdom
Number of recognized phyla
35
Clade
Groups of phyla
Monophyletic group with a common ancestor
How are phyla categorized?
Into clades based on shared characteristics
All animals share the earth which means
They have the same basic resources available (energy, oxygen, etc)
Monophyletic
A unique group of animals (phyla)
Lower clades branched more recently than higher clades
False, lower clades are more ancient
Earlier branches on the phyletic tree indicate
Bigger differences between groups
What is the first characteristic of an animal?
A multicellular eukaryote that lacks a cell wall
What is the second characteristic of an animal?
Heterotroph (eats other things for energy)
What is the third characteristic of an animal?
Motile for at least some time in their lives
What is the fourth characteristic of an animal?
Reproduces sexually (most) or asexually
What is the fifth characteristic of an animal?
Most have nerves and muscles (movement)
Precambrian era
700 mya
When multicellular eukaryotes started appearing
What did multicellular eukaryotes evolve from?
A flagellated protist
How did Multicellular eukaryotes arise?
Colonies formed that started specialization of tissues
What is a flagellated protist?
A colonial unicellular ancestor of eukaryotes
What did specialization and layering change in flagellated protists?
They were the first steps in becoming multicellular eukaryotes
Change in shape of multicellular colonies lead to
Internalization of functions
Choanoflagellates
Cone shaped cells with a flagella
Importance of Choanoflagellates
Similar to sponge cells (choanocytes) showing evolutionary link
Does evolution mirror development?
Yes, evidence of LUCA
