test3 bio2 ch32

List major characteristics of animals

multicellular and heterotrophic, absorptive nutrition, lack of cell walls, specialized tissue, ability to move

multicellular and heterotrophic (animals)

they are multicellular organisms that obtain energy by consuming other organisms, making them heterotrophs.

absorptive nutrition (animals)

they process their food internally, often with a digestive system that includes a mouth and an anus for efficient nutrient absorption

lack of cell walls (animals)

Instead, proteins like collagen provide structural support

specialized tissues (animals)

have tissues formed from embryonic layers, including unique nerve and muscle cells that enable movement and sensory functions

ability to move (animals)

thanks to their muscle and nerve tissues, which also help in detecting and capturing prey

possible reasons why the Cambrian Period led to a rapid increase in animal diversity

predator-prey dynamics, atmospheric oxygen increase, and genetic innovations

explain how predator-prey dynamics led to a rapid increase in animal diversity in the Cambrian Period

predators developed adaptations like claws, while prey evolved defenses such as protective shells, this arms race likely drove diversification

explain how atmospheric oxygen increase led to a rapid increase in animal diversity in the Cambrian Period

it supported animals with higher metabolic rates and larger body sizes, facilitating the evolution of diverse forms

explain how genetic innovations led to a rapid increase in animal diversity in the Cambrian Period

The development of Hox genes and new microRNAs, which are crucial for regulating gene expression, enabled the evolution of complex body structures

Bilateral Symmetry

characterized by having a distinct left and right side, with only one plane dividing the body into mirror-image halves

Explain why bilateral symmetry allowed for more active lifestyles in animals

because it allows for the concentration of sensory organs and a central nervous system at the head end, facilitating complex movements like crawling, burrowing, flying, or swimming, this arrangement supports coordinated movement and directional travel, which are essential for active foraging and predator evasion

diploblastic animals

Have two germ layers: ectoderm and endoderm, ex: jellyfish

triploblastic animals

Have three germ layers: ectoderm, mesoderm, and endoderm, ex: Vertebrates, arthropods

the embryonic tissue layers

ectoderm, mesoderm, endoderm

definition and the fate of the ectoderm embryonic tissue layer

Ectoderm forms the outer layer, fate: Becomes the outer body layer and nervous system

definition and the fate of the mesoderm embryonic tissue layer

the middle layer: forms muscles, skeleton, most internal organs, circulatory system, and more

definition and the fate of the endoderm embryonic tissue layer

inner layer, fate: Forms the lining of the digestive tract and organs like the liver and lungs

animals mostly reproduce…

sexually with a gametic life cycle

summarize the gametic life cycle

Meiosis: Occurs in germ cells to produce haploid gametes (sperm and eggs). These gametes do not undergo further cell division until fertilization, Fertilization: The fusion of haploid gametes results in a diploid zygote, Mitosis: The diploid zygote divides by mitosis, developing into a multicellular diploid organism.

protostome development

• Cleavage: Spiral and determinate, meaning the fate of each embryonic cell is determined early.

• Coelom Formation: Coelom forms from splits in the mesoderm.

• Blastopore Fate: The mouth develops from the blastopore.

Examples: Mollusks and annelids

deuterostome development

• Cleavage: Radial and indeterminate

• Coelom Formation: Coelom forms from mesodermal outpocketing of the archenteron.

• Blastopore Fate: The anus develops from the blastopore, with the mouth forming from a secondary opening.

Examples: Echinoderms and chordates

radial symmetry

Symmetry around a central axis, as in a starfish

coelom

a body cavity fully lined with mesoderm

psudocoelom

partially lined body cavity

spiral cleavage

diagonal cell division

radial cleavage

parallel or perpendicular cell division

determinate cleavage

fixes cell fate early

interminate cleavage

allows cells to develop into a complete organism

blastopore

The opening that forms during early embryonic development, leading to the digestive tract

choanoflagellates

Single-celled organisms considered the closest living relatives of animals