February 14 BIO What are animals and how are they related to other forms of life LO

List the shared derived traits and shared ancestral traits of animals. (You may have to look on the internet for this as your book doesn’t clearly list them all) 

Shared Derived Traits (Synapomorphies) of Animals: 

• Multicellularity 

• Heterotrophy (consuming organic material for energy) 

• Nerve cells and muscle cells (in most) 

• Embryonic development with a blastula stage 

• Mentioned in class: specific cell-cell junctions, extracellular matrix, blastula, hox genes, electrically excitable cells  

  Shared Ancestral Traits (Symplesiomorphies) of Animals: 

• Eukaryotic cells 

• Presence of mitochondria 

• Lack of cell walls 

• Mentioned in class: eukaryotes, heterotrophic, locomotion, multicellular, internal digestion  

Describe the body plan features of animals, including presence of tissues, body symmetry, early embryonic development, presence and type of body cavity, and segmentation, stating the potential advantages of each. 

Presence of Tissues 

• Advantage: Allows specialization of cells into organs and systems for efficient function. 

  Body Symmetry 

• Types: Radial or bilateral 

• Advantage: Bilateral symmetry allows for directional movement and better coordination. 

  Early Embryonic Development 

• Types: Protostome (mouth first) or deuterostome (anus first) 

• Advantage: Influences body structure and complexity in development. 

  Body Cavity 

• Types: Acoelomate, pseudocoelomate, coelomate 

• Advantage: A coelom (true body cavity) allows for organ development and flexibility. 

  Segmentation 

• Advantage: Provides flexibility and redundancy, allowing for specialized body parts and efficient movement. 

  Mentioned in Class: Cephalization 

• Sensory nerves concentrated in a particular region of the body 

• Usually in phylogeny trees the evolution of cephalization and bilateral symmetry coincide.

Draw a phylogenetic tree of the Metazoa, including the Porifera, Cnidaria, Platyhelminthes, Annelida, Mollusca, Nematoda, Arthropoda, Echinodermata, and Chordata, rooted with the Choanoflagellates as an outgroup. Label the groups according to Protosome vs Deuterostome and Lophotrochozoa vs Ecdysozoa. On the same phylogenetic tree, label the characters that distinguish each clade, using the developmental and body plan features listed in learning outcome #2. 

look at the picture in bio LO notes!

Explain the colonial flagellate hypothesis of metazoan origin and why it is currently favored. 

The colonial flagellate hypothesis suggests that metazoans (animals) originated from a colonial group of flagellated protists. These protists lived in a colony, with cells working together, and over time, some cells became specialized, leading to the formation of true multicellular animals. 

It is favored because: 

• Molecular and genetic evidence shows similarities between modern animals and certain flagellates (e.g., choanoflagellates). 

• The hypothesis explains the transition from unicellular to multicellular life and the development of specialization in cells. 

Human evolution? 

idk bro u tell me

Describe a) the domain, kingdom, phylum, class, order, family, genus, and species that contains humans, b) the characteristics that humans share with other mammals and with other apes, c) the characteristics that distinguish humans from other apes, d) the closest relatives to humans within and outside the genus Homo, and e) what is known about the timing of the emergence of humans from closely related species. 

a) Taxonomy of Humans: 

• Domain: Eukarya - Kingdom: Animalia - Phylum: Chordata - Class: Mammalia - Order: Primates - Family: Hominidae - Genus: Homo - Species: Homo sapiens 

  b) Characteristics Humans Share with Other Mammals and Apes: 

• Mammals: Warm-blooded, hair/fur, live births, mammary glands 

• Apes: Large brains, forward-facing eyes, complex social structures 

  c) Characteristics that Distinguish Humans from Other Apes: 

• Bipedalism (walking on two legs) 

• Larger brain size relative to body 

• Ability for complex language and abstract thought 

• Use of tools and culture 

  d) Closest Relatives to Humans: 

• Within genus Homo: Homo neanderthalensis (Neanderthals), Homo erectus 

• Outside genus Homo: Chimpanzees and bonobos (genus Pan) 

  e) Timing of Human Emergence: 

• Humans (Homo sapiens) emerged around 300,000 years ago from a common ancestor shared with other species like Neanderthals and Homo erectus.